Magnetic solidphaseextraction was tested for the preconcentration of non-ionic surfactants based on oxyethylated nonylphenol, aliphatic alcohols and hydrogenated fatty acid methyl esters from water. Magnetic hydrophobic adsorbents exhibited the best extraction characteristics. Surfactants with the middle oxyethylation level were extracted efficiently while the extraction of surfactants with low and high oxyethylation levels was very low.
Magnetic solid-phaseextraction is a new procedure for the preconcentration of target analytes from large volumes based on the use of magnetic or magnetizable adsorbents. In the experiments reactive copper phthalocyanine dye attached to silanized magnetite, and magnetic charcoal were used as adsorbents and selected organic dyes were used as analytes. Up to 460-fold enrichment of analytes was observed.
In this study, a developed technique was reported for extraction and pre-concentration of methamphetamine (MAMP) and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) from urine samples using molecularly imprinted-solidphaseextraction (MISPE) along with simultaneous derivatization and dispersive liquid-liquid microextraction (DLLME). Molecularly imprinted microspheres as sorbent in solidphaseextraction (SPE) procedure were synthesized using precipitation polymerization with MAMP as the template. Aqueous solution of the target analytes was passed through MAMP-MIP cartridge and the adsorbed analytes were then eluted with methanol. The collected eluate was mixed with butylchloroformate which served as the derivatization reagent as well as the extraction solvent. The mixture was immediatel...
In this study, alumina-coated magnetite nanoparticles (Fe3O4/Al2O3 NPs) were synthesized, and they were applied to the analysis of sulfonamides (SAs) including sulfadiazine (SDZ), sulfamerazine (SMR), sulfamethoxazole (SMX), sulfamonomethoxine (SMM), sulfamethoxydiazine (SMD), sulfadimethoxine (SDM) and sulfaquinoxaline (SQX) in different soil samples based on magnetic solid-phaseextraction (MSPE). The extraction and concentration process was carried out in a single step by mixing the extraction solvent, magnetic adsorbents and soil sample under ultrasonic action. Then, the adsorbents were isolated from the complicated matrix easily with an external magnetic field. The SAs desorbed from the adsorbents were determined by liquid chromatography-tandem mass spectrometry. Compared with traditi...
A molecularly imprinted polymer (MIP) was prepared using chlorsulfuron (CS), a herbicide as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a cross-linker, methanol and toluene as a porogen, and 2,2-azobisisobutyronitrile as an initiator. The binding behaviors of the template chlorsulfuron and its analog on MIP were evaluated by equilibrium adsorption experiments, which showed that the MIP particles had specific affinity for the template CS. Solid-phaseextraction (SPE) with the chlorsulfuron molecularly imprinted polymer as an adsorbent was investigated. The optimum loading, washing, and eluting conditions for chlorsulfuron molecularly imprinted polymer solid-phaseextraction (CS-MISPE) were established. The optimized CS-MISPE proced...
A new approach to performing extraction and preconcentration employing functionalized magnetic nanoparticles for the determination of trace metals is presented. Alumina-coated iron oxide nanoparticles were synthesized and used as the solid support. The nanoparticles were functionalized with sodium dodecyl sulfate and used as adsorbents for solidphaseextraction of the analyte. Extraction, elution, and detection procedures were performed sequentially in the sequential injection lab-on-valve (SI-LOV) system followed by electrothermal atomic absorption spectrometry (ETAAS). Mixtures of hydrophobic analytes were successfully extracted from solution using the synthesized magnetic adsorbents. The potential use of the established scheme was demonstrated by taking cobalt as a model analyte. Under...
Magnetic solidphaseextraction (MSPE) is proposed as a simple and fast method for the preconcentration of free middle oxyethylated nonylphenols (NPs) from water. Middle oxyethylated NPs were extracted by MSPE from different water samples (10 and 500 ml samples of distilled, potable, well, river and pond water in concentrations of 30 and 0.6 ?g ml-1) using magnetically modified polyphenyleneoxide, Tenax TA and Tenax GR as magnetic adsorbents. Recoveries were 80 100% and relative standard deviations were less than 10%.
Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential single-walled carbon nanotubes (SWCNTs) as solid-phase microextraction (SPME) adsorbents for the preconcentration of environmental pollutants have been investigated in recent years. The goal of this work was to investigate the feasibility of SWCNTs used as adsorbents for solid-phase microextraction of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) in human urine. SWCNTs were attached onto a stainless steel wire through organic binder. Potential factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, desorption time, desorption temperature, and s...
Leakage of the residual template molecules is one of the biggest challenges for application of molecularly imprinted polymer (MIP) in solid-phaseextraction (SPE). In this study, bisphenol F (BPF) was adopted as a dummy template to prepare MIP of bisphenol A (BPA) with a superparamagnetic core-shell nanoparticle as the supporter, aiming to avoid residual template leakage and to increase the efficiency of SPE. Characterization and test of the obtained products (called mag-DMIP beads) revealed that these novel nanoparticles not only had excellent magnetic property but also displayed high selectivity to the target molecule BPA. As mag-DMIP beads were adopted as the adsorbents of solid-phaseextraction for detecting BPA in real water samples, the recoveries of spiked samples ranged from 84.7% to 93.8% with the limit of detection of 2.50 pg mL(-1), revealing that mag-DMIP beads were efficient SPE adsorbents. PMID:22365123
In the present study, a novel quantitative method, namely magnetic nanoparticle-based solid-phaseextraction (MSPE), was applied to extract vitamin B12 from pharmaceutical formulations. The technique involves the use of Fe3O4 nanoparticles modified by sodium dodecyl sulfate (SDS) as an efficient adsorbent for solid-phaseextraction of vitamin B12. Collection of magnetic nanoparticles (MNPs) from aqueous solution was simply achieved by applying external magnetic field. The analyte was desorbed from MNPs using alkali 1-propanol. The extracted analyte was analyzed by using flow injection inductively coupled plasma?optical emission spectrometry. Factors affecting the extraction efficiency were investigated and optimized. Under the optimum conditions, enhancement factor of 184, linear dynamic r...
The effects of sorbent saturation in thin adsorbent layers have been much overlooked in earlier research and should be taken into account in both the theory and practice of solid-phaseextraction (SPE) and solid-phase microextraction (SPME). The adsorption kinetics of a single analyte into a thin adsorptive layer was modeled for several cases of agitation conditions in the analyzed volume. The extraction process in the adsorbent layer was modeled using a Langmuir isotherm approximated by the linear isotherm at low concentrations and by a saturation plateau at concentrations exceeding the critical saturation concentration. Laplace transformations were used to estimate the equilibration time and adsorbed analyte concentration profile for no agitation, practical and perfect agitation in the analyzed volume. The equilibration time may be significantly reduced at high degrees of oversaturation and/or agitation in the analyzed volume. The resulting models indicated that the adsorbent layer becomes saturated at some critical value of the oversaturation degree parameter. The critical value of the oversaturation parameter is affected by both the concentration of the analyte in the analyzed volume and the sorbent characteristics. It was also shown that the adsorption process is carried out via the propagation of the saturation adsorption boundary toward the inner boundary of the adsorbent layer. These new adsorption models should serve as "stepping stones" for the development of competitive adsorption kinetic models for both SPE and SPME, particularly in cases where fast sampling is used. PMID:10757283
Abstract In this study, an extraction and preconcentration technique using solid-phaseextraction (SPE) along with hollow fiber (HF) has been developed as an ultra-preconcentration technique for some triazole pesticides in aqueous samples. Triazole pesticides were employed as model compounds to assess the method and were monitored by gas chromatography-flame ionization detection (GC-FID). Initially, an aqueous solution of target analytes was passed through an RP-8 SPE cartridge and then the adsorbed analytes were eluted with L amounts of toluene. The collected elute was slowly introduced into an HF that had one end blocked. This allowed precipitation inside the lumen and pores of the HF. Finally, the obtained HF was mounted on a home-made solid-phase microextraction syringe and entered int...
Leakage of the residual template molecules is one of the biggest challenges for application of molecularly imprinted polymer (MIP) in solid-phaseextraction (SPE). In this study, bisphenol F (BPF) was adopted as a dummy template to prepare MIP of bisphenol A (BPA) with a superparamagnetic core-shell nanoparticle as the supporter, aiming to avoid residual template leakage and to increase the efficiency of SPE. Characterization and test of the obtained products (called mag-DMIP beads) revealed that these novel nanoparticles not only had excellent magnetic property but also displayed high selectivity to the target molecule BPA. As mag-DMIP beads were adopted as the adsorbents of solid-phaseextraction for detecting BPA in real water samples, the recoveries of spiked samples ranged from 84.7% ...
In this paper, a graphene-based Fe3O4 magnetic nanoparticles (G-Fe3O4 MNPs) was used as the adsorbent for the magnetic solid-phaseextraction of some triazine herbicides (atrazine, prometon, propazine and prometryn) in environmental water samples followed by high performance liquid chromatography-diode array detection (HPLC-DAD). After the extraction, the adsorbent can be conveniently separated from the aqueous samples by an external magnet. The main factors influencing the extraction efficiency including the amount of the MNPs, the extraction time, the pH of sample solution, and desorption conditions were studied and optimized. Under the optimized experimental conditions, a good linearity was observed in the range of 0.1-50.0ngmL^-^1 for all the analytes, with the correlation coefficients...
Magnetic solidphaseextraction (MSPE) is proposed as a simple and fast method for the preconcentration of free middle oxyethylated nonylphenols (NPs) from water. Middle oxyethylated NPs were extracted by MSPE from different water samples (10 and 500 ml samples of distilled, potable, well, river and pond water in concentrations of 30 and 0.6 {mu}g ml{sup -1}) using magnetically modified polyphenyleneoxide, Tenax TA and Tenax GR as magnetic adsorbents. Recoveries were 80-100% and relative standard deviations were less than 10%.
In this paper, a simple and cheap method for the simultaneous preconcentration and sensitive determination of three hexabromocyclododecane (HBCD) diastereomers (?-, ?-, and ?-HBCD) in environmental water samples has been developed. It was based on solidphaseextraction (SPE) and rapid resolution liquid chromatography?electrospray tandem mass spectrometry. Bamboo charcoal, one kind of cheap material, was investigated and used as SPE adsorbent for the enrichment and determination of HBCD diastereomers. Related important parameters affecting extraction efficiencies, including type and volume of eluant, amount of sorbent, sample pH, flow rate, and sample volume, were investigated and optimized in detail. Under the optimum conditions, experimental data exhibited excellent linear relationships ...
Solid-phaseextraction has been widely employed for the preparation of DNA templates for polymerase chain reaction (PCR)-based analytical methods. Among the variety of adsorbents studied, magnetically responsive silica particles are particularly attractive due to their potential to simplify, expedite, and automate the extraction process. Here we report a facile method for the preparation of such magnetic particles, which entails impregnation of porous silica microspheres with iron salts, followed by calcination and reduction treatments. The samples were characterized using powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherms, and vibrating sample magnetometry (VSM). XRD data show that magnetite nanocrystals of about 27.2nm are prod...
This paper demonstrates, for the first time, the great potential of using Zn/Al layered double hydroxide intercalated sodium dodecyl benzene sulfonate (Zn/Al-SDBS-LDH) as a solid-phaseextraction (SPE) material in the extraction of persistent organic pollutants prior to the determination of gas chromatography?mass spectrometry in environmental water samples. Zn/Al-SDBS-LDH, a relatively inexpensive and simply prepared material, was synthesized and used as a SPE adsorbent to quantitatively determine the concentration of five polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Factors affecting extraction efficiency, such as, eluent type, eluent volume, flow rate of sample, sample volume, and amount of adsorbent, were investigated and optimized in detail. Experimental res...
This report contains a general introduction which discusses solid-phaseextraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phaseextraction; a new, high-capacity carboxylic acid functionalized resin for solid-phaseextraction; semi-micro solid-phaseextraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.
This study developed and validated a method of measuring the feminizing chemicals 4-tert-octylphenol, 4-nonylphenol, nonylphenol monoethoxycarboxylate (NP1EC), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), estrone, 17b-estradiol, estriol, 17a-ethinyl estradiol and bisphenol A in river water, sediment, and tissue using ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) and isotope-dilution techniques. Water samples were pretreated using disk-type automated solid-phaseextraction (SPE). Solid samples of sediment, fish, and clams were treated with matrix solid-phase dispersion (MSPD) using C8 adsorbent. Eluents were directly passed following alumina cartridges for cleanup. The signal intensity of analytes on electrospray ionization (ESI...
A graphene-based magnetic nanocomposite (graphene-ferriferrous oxide; G-Fe(3)O(4)) was synthesized and used as an effective adsorbent for the preconcentration of some triazole fungicides (myclobutanil, tebuconazole, and hexaconazole) in environmental water samples prior to high-performance liquid chromatography-ultraviolet detection. The method, which takes the advantages of both nanoparticle adsorption and magnetic phase separation from the sample solution, could avoid the time-consuming experimental procedures commonly involved in the traditional solidphaseextraction such as centrifugation and filtrations. Various experimental parameters affecting the extraction efficiencies such as the amount of the magnetic nanocomposite, extraction time, the pH values of the sample solution, salt concentration, and desorption conditions were investigated. Under the optimum conditions, the enrichment factors of the method for the three analytes were 5824, 3600, and 4761, respectively. A good linearity was observed in the range of 0.1-50 ng/mL for tebuconazole and 0.05-50 ng/mL for myclobutanil and hexaconazole, respectively, with the correlation coefficients ranging from 0.9992 to 0.9996. The limits of detection (S/N = 3) of the method were between 0.005 and 0.01 ng/mL. The results indicated that as a magnetic solid-phaseextractionadsorbent, the graphene-ferriferrous oxide (G-Fe(3)O(4)) has a great potential for the preconcentration of some compounds from liquid samples. PMID:22715113
Triphenylamine (TPA)-functionalized magnetic microspheres (Fe(3)O(4)/SiO(2)/TPA) were prepared and applied as solidphaseextraction (SPE) adsorbents for the analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental samples in combination with high-performance liquid chromatography (HPLC). The magnetic solid-phaseextraction (MSPE) conditions affecting the extraction efficiency were optimized, including elution solvent, standing time, amount of sorbent, and salt concentration. Due to the strong ?-? conjugate effect between the benzene rings of TPA and PAHs, high extraction efficiency was achieved with spiked recoveries of 80.21-108.33% and relative standard deviations (RSD) of less than 10%. Good linearities (R(2) > 0.997) for all calibration curves were obtained with low limits of detection (LOD) of 0.25, 0.5, 0.5, 3.75, 0.2 and 0.04 ng L(-1) for anthracene, fluoranthene, pyrene, chrysene, benzo[b]fluoranthene and benzo[k]fluoranthene, respectively. The achieved results indicate the applicability of Fe(3)O(4)/SiO(2)/TPA as MSPE adsorbents. PMID:22534731
Calixarenes are a class of host molecules with three-dimensional cavity capable of accepting guest molecules. The interest of calixarenes in analytical and separation chemistry has increased in recent years because of their ability to form reversible complexes with both neutral and charged molecules. Calixarenes have been utilized in gas chromatography, solid-phaseextraction, capillary electrophoresis and overall in high performance liquid chromatography. This short review is focused on recent advances in synthesis and characterization of calixarene, calixresorcinarene and calixpyrrole stationary phases, chemically bonded or dynamically adsorbed onto silica gel or used as mobile phase additives, and its application to separation of organic and inorganic solutes by high performance liquid ...
Landfill leachate comprises a complex mixture of contaminants many of which may have multiple sources in the environment confounding conventional techniques for apportioning sources. Compound specific isotope ratio mass spectrometry offers the potential to "fingerprint" compounds enabling discrimination to be made between different sources. This paper presents a rapid and highly reproducible method to prepare landfill leachate samples for compound specific isotope analysis. A suitable solidphaseextraction (SPE) method was developed using artificial contaminant solutions, natural waters spiked with artificial contaminants (eucalyptol, dodecane, benzothiazole, dibutyl phthalate and naphthalene), and samples of landfill leachate. The elution of adsorbed compounds from the SPE cartridge was ...
A computational approach was applied to screen functional monomers and polymerization solvents for rational design of molecular imprinted polymers (MIPs) as smart adsorbents for solid-phaseextraction of clonazepam (CLO) form human serum. The comparison of the computed binding energies of the complexes formed between the template and functional monomers was conducted. The primary computational results were corrected by taking into calculation both the basis set superposition error (BSSE) and the effect of the polymerization solvent using the counterpoise (CP) correction and the polarizable continuum model, respectively. Based on the theoretical calculations, trifluoromethyl acrylic acid (TFMAA) and acrylonitrile (ACN) were found as the best and the worst functional monomers, correspondingl...
A novel method was developed for solid-phaseextraction (SPE) of perfluorinated compounds (PFCs) from environmental water samples using cetyltrimethylammonium bromide (CTAB) coated Fe3O4 nanoparticles (Fe3O4 NPs) as an adsorbent. The magnetic nanosized adsorbent has a large surface area and superparamagnetic properties. This gives it a high extraction capacity and allows for convenient isolation by a magnetic field. Compared with other SPE methods and our previous work on PFCs, this method exhibited a fairly good analytical performance and required a small amount of sorbent (50mg) and short pretreatment times (30min) for 800mL environmental water samples. Seven PFCs, including perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecan...
A new method was developed for the speciation of inorganic arsenic in environmental water by using selective magnetic solid-phaseextraction followed by inductively coupled plasma mass spectrometry. It is found that As(V) selectively adsorbed on amino-modified silica-coated magnetic nanoparticles (MNPs) in the pH range from 3 to 8, while As(III) is not be retained. The As(V)-loaded MNPs can be separated easily from the aqueous sample solution by simply applying an external magnetic field. The adsorbed As(V) was quantitatively recovered from the MNPs using using 1?M nitric acid. Total inorganic As was extracted after the permanganate oxidation of As(III) to As(V). Parameters affecting the separation were investigated systematically, and the optimal separation conditions were established. Un...
A microscale solid-phaseextraction (SPE) method using alumina-coated iron oxide nanoparticles (Fe3O4l2O3 NPs) as the affinity adsorbent for glyphosate (GLY) and its major metabolite aminomethylphosphonic acid (AMPA) in aqueous solution is reported. One milligram of Fe3O4l2O3 NPs was employed to extract both analytes in 5ml of aqueous solution. After 5min extraction, magnetic NPs were isolated from sample solution by employing an external magnet. Followed by rinsing the NPs with 5ml of 20mM Na4P2O7 solution for 5min, the extract was directly analyzed using the derivatization-free CE-electrochemiluminescence (CE-ECL) method. With a sample-to-extract volume ratio of 1000, the enrichment factors for GLY and AMPA were 460 and 64, respectively. The limits of detection (LODs) were 0.3 and 30ngml...
In this study, the new C18-functionalized ultrafine magnetic silica nanoparticles (C18-UMS NPs) were successfully synthesized and applied for extraction of sudan dyes in water samples based on the magnetic solid-phaseextraction (MSPE). The extraction and concentration were carried out in one step by blending C18-UMS NPs and water samples. The sudan dyes adsorbed C18-UMS NPs were isolated from the matrix easily with an external magnetic field. After desorption the quantitation of sudan dyes was done by ultra fast liquid chromatography (UFLC). Satisfactory extraction recovery can be obtained with only 50mgC18-UMS NPs. The effects of experimental parameters, including the amount of the nanoparticles, extraction time, pH value, desorption solvent, volume of desorption solvent and desorption t...
Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential single-walled carbon nanotubes (SWCNTs) as solid-phase microextraction (SPME) adsorbents for the preconcentration of environmental pollutants have been investigated in recent years. The goal of this work was to investigate the feasibility of SWCNTs used as adsorbents for solid-phase microextraction of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) in human urine. SWCNTs were attached onto a stainless steel wire through organic binder. Potential factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity. The developed method showed good performance according to the ICH performance criteria for bioanalytical methods. The calibration curves of the ethers were linear (r(2)>or=0.992) in the range from 10 to 5000 ng L(-1). The limits of detection at a signal-to-noise (S/N) ratio of 3 were 10 ng L(-1) for all the analytes. In addition, compared with the commercial carboxen/polydimethylsiloxane (CAR/PDMS) fiber, the SWCNT fiber showed better thermal stability (over 350 degrees C) and longer life span (over 150 times). The developed method was applied successfully to determine trace level of the ethers in urine of 10 healthy male volunteers. PMID:19395320
In the present study, a novel quantitative method, namely magnetic nanoparticle-based solid-phaseextraction (MSPE), was applied to extract vitamin B(12) from pharmaceutical formulations. The technique involves the use of Fe(3)O(4) nanoparticles modified by sodium dodecyl sulfate (SDS) as an efficient adsorbent for solid-phaseextraction of vitamin B(12). Collection of magnetic nanoparticles (MNPs) from aqueous solution was simply achieved by applying external magnetic field. The analyte was desorbed from MNPs using alkali 1-propanol. The extracted analyte was analyzed by using flow injection inductively coupled plasma-optical emission spectrometry. Factors affecting the extraction efficiency were investigated and optimized. Under the optimum conditions, enhancement factor of 184, linear dynamic range of 2.5-500 ?g L(-1) with correlation of determination (R(2) > 0.999), and limit of detection of 1.0 ?g L(-1) were obtained for vitamin B(12). The percent relative standard deviation based on five-replicate determination was less than 6.2%. The method was successfully applied for extraction and determination of vitamin B(12) in different types of pharmaceutical samples such as multivitamin tablet, effervescent tablet, and injection sample. The results showed that the proposed method based on SDS-Fe(3)O(4) MSPE was a simple, accurate, and highly efficient approach for analysis of vitamin B(12). PMID:22187326
A new method that utilizes asparagine modified attapulgite as a solidphaseextractant has been developed for preconcentration of trace Fe(III) prior to the measurement by inductively coupled plasma optical emission spectrometry. Characterization of the surface modification was performed on the basis of Fourier transform infrared spectra. The separation/preconcentration conditions of the analyte were investigated, including the pH value, the shaking time, the sample ow rate and volume, the elution condition and the interfering ions. At pH 4, the new adsorbent had relatively high capacity and enrichment factor compared to other methods reported so far. The adsorbed Fe(III) was quantitatively eluted by 2mL of 0.5molL^-^1 HCl. Common coexisting ions did not interfere with the separation. The ...
A solidphaseextraction (SPE) preconcentration system, coupled to a flame atomic absorption spectrometer (FAAS), was developed for the determination of copper(II), cadmium(II), lead(II), manganese(II), iron(III), nickel(II) and cobalt(II) ions at the mgL-1 levels on Penicillium italicum - loaded on Sepabeads SP 70. The analytes were adsorbed on biosorbent at the pH range of 8.5-9.5. The adsorbed metals were eluted with 1molL-1 HCl. The influences of the various analytical parameters including pH of the aqueous solutions, sample volume, flow rates were investigated for the retentions of the analyte ions. The recovery values are ranged from 95-102%. The influences of alkaline, earth alkaline and some transition metal ions were also discussed. Under the optimized conditions, the detection li...
A simple and rapid method for the in situ preconcentration of trace dissolved sulfide in environmental water samples has been developed based on solid-phaseextraction using Sep-Pak C18 cartridges. Dissolved sulfide in water samples, which was taken into a graduated syringe to prevent the oxidation of sulfide by air, was reacted with N,N-dimethyl-p-phenylene-diamine sulfate and iron(III) chloride to be converted into Methylene Blue immediately after sample collection. The formed Methylene Blue was adsorbed on Sep-Pak C18, which was stable on Sep-Pak C18 for at least 30 d. The adsorbed Methylene Blue was eluted with a mixture of methanol and 0.01 M hydrochloric acid. The color intensity due to the Methylene Blue was measured at 659 nm. The proposed method is applicable to brackish and sea water samples as well as freshwater.
In the present study, a novel synthesized adsorbent material based on 3-mercaptopropyltrimethoxysilane-functionalized multi-walled carbon nanotubes was used to increase the Pb2+ adsorption from aqueous solutions in a flow injection solid-phaseextraction system coupled to flame atomic absorption spectrometry. Spectroscopic and microscopic techniques (Fourier transform infrared spectroscopy, energy dispersive spectroscopy, and scanning electron microscopy) were employed to confirm the chemical modification of the adsorbent surface. Preconcentration conditions (sample pH, flow rate, buffer solution, and eluent concentrations) were optimized using factorial and Doehlert matrix designs that made it possible to construct a linear graph in the 5.0- to 130.0-?g?L?1 range (r?=?0.9999) and estimate...
A selective solid-phaseextraction procedure using chemically modified Amberlite XAD-4 with monoaza dibenzo 18-crown-6 ether was investigated for the preconcentration and separation of La(III), Nd(III) and Sm(III) in synthetic solution. Before loading samples on synthesized adsorbent adjust pH 4.5 by suitable buffer solution. The adsorbed rare earth elements were eluted by 2M hydrochloric acid. Various parameters like preconcentration, breakthrough capacity, flow rate were investigated. The limits of detection (n=5) and limits of quantification (n=5) for La(III), Nd(III) and Sm(III) were founded 3.9, 4.2 and 7.4mgL-1 and 13, 15 and 26mgL-1, respectively. The eluted metal ions were determined by ICP-AES.
An efficient analytical method for the preconcentration and determination of phosphate in water samples at trace levels was proposed. The method was based on sample enrichment using dispersive solid-phaseextraction (dSPE) with tetraethylenepentamine (TEPA)-functionalized nano-size composite materials (TEPA-NCMs) as sorbents, which were fully characterized. Various parameters affecting the extraction efficiency were systematically investigated. After extraction, the post-adsorbed TEPA-NCMs were eluted by a NaOH solution for desorption of the phosphate. The resulting eluate containing phosphate was determined by a spectrophotometric method. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.29 and 0.96 ?g L?1, respectively. The relative standard deviations (RSDs) were lower than 8.0% with average recoveries ranging from 91 to 118%. The present method was successfully applied to the determination of phosphate at trace levels in real water samples, and it was confirmed that the TEPA-NCMs are highly effective dSPE materials.
We present a study on the application of magnetic nanoparticles (MNPs) prepared from Fe3O4 and functionalized with pyridine as an adsorbent for the solid-phaseextraction of trace quantities of Pd(II) ion. The pyridine group was immobilized on the surface of the MNPs by covalent bonding of isonicotinamide. The modified MNPs can be readily separated from an aqueous solution by applying an external magnetic field. Effects of pH, the amount of functionalized MNPs, extraction time, type and quantity of eluent, desorption time, break-through volume and interfering ions on the extraction efficiency were optimized. The amount of Pd(II) was then determined using FAAS. Under the optimized conditions, the detection limit and preconcentration factor are 0.15??g?L-1 and 196, respectively, and the rela...
The presented study investigates application of decanoic acid-coated Fe3O4 nanoparticles as an adsorbent for solidphaseextraction and determination of trace amounts of Cd, Co, Cr, Ni, Pb and Zn from environmental water samples using flow injection inductively coupled plasma-optical emission spectrometry (ICP-OES). Magnetic nanoparticles (MNPs), carrying target metals, were easily separated from the aqueous solution by applying an external magnetic field; so, no filtration or centrifugation was necessary. After extraction and collection of MNPs, the analytes were desorbed using 0.25molL^-^1 of HCl in propanol. The desorbed analytes were introduced into the nebulizer of ICP-OES by using flow injection technique. Effects of pH, chelating agent, extraction time, type of eluent, desorption ti...
In this work, magnetic multiwalled carbon nanotubes were synthesized through a facile hydrothermal process, and then successfully used as magnetic solid-phaseextraction sorbents for the determination of p-hydroxybenzoates in beverage. The prepared magnetic multiwalled carbon nanotubes presented both satisfactory superparamagnetism and strong capacity of absorption, with magnetic Fe(3)O(4) beads of 200 nm average diameters decorated at either ends of the tubes. The hybrid nanocomposites showed a high efficiency in the extraction and enrichment of p-hydroxybenzoates via ?-? stacking of targeted molecules onto the polyaromatic composed surface of multiwalled carbon nanotubes, which entitled them promising magnetic solid-phaseextraction sorbents for p-hydroxybenzoates at trace level from complex drink samples. By using an external magnetic field, p-hydroxybenzoates adsorbed on magnetic multiwalled carbon nanotubes could be rapidly isolated in only 30 s, and subsequently analyzed by liquid chromatography-diode array detector after elution with organic solvents. Extraction conditions such as eluting solvent, the amounts of magnetic sorbents added, pH values, adsorption and desorption time were investigated and optimized to achieve the best effect. Method validations including linearity, detection limit, and precision were also studied. The linearities were in the wide range of 0.05-500 ?g/mL with correlation coefficients higher than 0.9983 for all p-hydroxybenzoates. The limits of detection were less than 20 ng/mL. Acceptable RSDs were achieved within 5-8% for all analytes. The results indicated that the proposed method based on magnetic multiwalled carbon nanotubes as magnetic solid-phaseextraction absorbents was rapid, efficient, and convenient for the analysis of the targeted compounds of p-hydroxybenzoates in beverage sample. PMID:22761146
Refractory 4,6-dimethyldibenzothiophene, which is difficult to remove from petroleum feedstocks, binds to the Ru in Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} by displacing the H{sub 2}O ligand. Thiophene, benzothiophene and dibenzothiophene (DBT) also react with Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} similarly. This binding ability of Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} has been used to remove over 50% of the DBT in simulated petroleum feedstocks by a biphasic extraction process. The extraction phase is readily regenerated by air-oxidation thereby completing a cyclic process that removes DBT from petroleum feedstocks. Solidphaseextractants consisting of Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+}, CpRu(CO){sub 2}(BF{sub 4}), CpFe(CO){sub 2}(C{sub 4}H{sub 8}){sup +} and AgX (where X = BF{sub 4}{sup -}, PF{sub 6}{sup -} or NO{sub 3}{sup -}) adsorbed on silica have also been used to remove DBT and 4,6-Me{sub 2}DBT from simulated petroleum feedstocks. The AgX/silica adsorbents remove 90% of the DBT and 4,6-Me{sub 2}DBT and can be regenerated and re-used for multiple extractions, which makes these adsorbents of potential industrial use for the removal of refractory dibenzothiophenes from petroleum feedstocks.
In this study, a developed technique was reported for extraction and pre-concentration of methamphetamine (MAMP) and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) from urine samples using molecularly imprinted-solidphaseextraction (MISPE) along with simultaneous derivatization and dispersive liquid-liquid microextraction (DLLME). Molecularly imprinted microspheres as sorbent in solidphaseextraction (SPE) procedure were synthesized using precipitation polymerization with MAMP as the template. Aqueous solution of the target analytes was passed through MAMP-MIP cartridge and the adsorbed analytes were then eluted with methanol. The collected eluate was mixed with butylchloroformate which served as the derivatization reagent as well as the extraction solvent. The mixture was immediately injected into deionized water. After centrifugation, 1 ?L of the settled organic phase was injected into gas chromatography-flame ionization detection (GC-FID) or gas chromatography-mass spectrometry (GC-MS). Various experimental parameters affecting the performance of both of the steps (MISPE and DLLME) were thoroughly investigated. The calibration graphs were linear in the ranges of 10-1500 ng mL(-1) (MAMP) and 50-1500 ng mL(-1) (MDMA), and the detection limits (LODs) were 2 and 18 ng mL(-1), respectively. The relative standard deviations (%RSDs) obtained for six repeated experiments (100 ng mL(-1) of each drug) were 5.1% and 6.8% for MAMP and MDMA, respectively. The relative recoveries obtained for the analytes in human urine samples, spiked with different levels of each drug, were within the range of 80-88%. PMID:22704883
A method for the isolation of bio-active primary fatty acid amides (PFAM's) from total lipid extract by solid-phaseextraction (SPE) was developed and validated. The lowest mass of amide to be loaded and recovered by this method was detected as 0.5 microg using 500 mg of normal phase adsorbent. The isolated PFAM's were separated and quantified by GC/MS and percent recoveries were calculated. An HP-5MS column was able to provide base line separation between the saturated and unsaturated PFAM's whereas clear resolution between geometric and positional isomers having the same number of carbons was obtained using a BPX70 column. The separated amides were all 18 carbon analogs of cis-9-octadecenoamide (oleamide). Detection limits in the single ion monitoring mode were found to be on the order of 10 pg in a 1 microl injection. Solidphaseextraction of amides from total lipid extract before GC/MS analysis provides clean detection and interference free analysis. PMID:16266715
The operation of an OTEC plant will result in the mixing of large volumes of seawater from different depths within the ocean. Because suspended particulate material is intimately involved in marine food webs and transition metals, such as copper, can have toxic effects, it is important to develop a sound methodology for characterizing and quantifying transition metal behavior associated with the solid material. The characterization of solid-phase-associated transition metals in the marine environment has largely been directed at marine sediments. These studies have generally indicated that it is not possible to uniquely identify the solidphases or chemical speciation of a given metal. There are many reasons for this difficulty, but the probable major analytical problems arise from the fact that many of the transition metals of interest are present only in trace concentrations as adsorbed species on amorphous oxides or as coprecipitates. In one approach transition metals are classified according to how easily they are solubilized when exposed to different types of chemical attack, as defined in chemical extraction schemes. In this study, several of the most widely accepted extraction techniques were compared for many of the most commonly measured transition metals to a variety of marine sediments. Based on the results of this study, the sequential extraction scheme of Tessler et al. (1979) is the recommended method for the characterization of solid-phase associated transition metals. An increase of the reducing agent concentration in the intermediate step and temperature decrease with an additional HCl digestion in the residual step are recommended as improvements, based on the results of the individual extraction method studies.
The solid-phaseextraction (SPE) method for the preconcentration of trace amounts of cadmium using synthetic zeolite A-4 and its determination by graphite furnace atomic absorption spectrometry (GFAAS) was investigated. The preconcentration conditions, such as the optimum pH range of the sample solution for the adsorption of cadmium and the kind of acid solution for dissolving the cadmium-adsorbed synthetic zeolite A-4, as well as the measurement conditions for the determination of cadmium by GFAAS, e.g., the ashing and atomizing temperature, were investigated. Quantitative recovery of cadmium onto zeolite A-4 from the sample solution over the pH range 2.0 - 9.0 was achieved by the batch method. After the solid-phase (cadmium-adsorbed zeolite A-4) was separated from the sample solution by a membrane filter, it was dissolved in 2.0 cm3 of 2.0 mol dm-3 nitric acid. An aliquot of the resulting solution was injected into the graphite furnace. In GFAAS measurements an alternate gas (Ar, 90%; O2, 10%) was used as a sheath gas, and the ashing temperature and atomizing temperature were 400°C and 1600°C, respectively. The detection limit (3 ?) for cadmium was 0.002 µg dm-3. The relative standard deviation at 0.010 µg dm-3 was 3.5 - 4.5% (n = 5). The proposed method has been successfully applied to the analysis of trace cadmium in environmental water samples.
Speciation and separation of chromium (VI) and chromium (III) from aqueous solutions were investigated using amino-propyl functionalised mesoporous silica (AP-MCM-41) as an adsorbent. The as-synthesised adsorbent was produced following a simple synthesis method at room temperature prior to template removal using microwave digestion. The maximum adsorption capacity at 111.1 mg/g was calculated according to the Langmuir isotherm model, suggesting a 1:1 monolayer adsorption mechanism. Moreover, AP is a simple chelate, yet it can extract Cr (VI) exclusively from solutions containing other mixed metal ions simply by tuning the solution pH. Recovery of Cr (VI) from loaded sorbents is equally easy to perform with 100% extraction efficiencies allowing reuse of the sorbent and recovery of Cr (VI) from aqueous solutions containing a complex mixture of ions. The material would find use in environmental remediation applications, as a selective adsorbent of Cr (VI) or even as a solid-phaseextraction stationary phase to remove and pre-concentrate Cr (VI) from aqueous solutions; this study demonstrates enrichment factors of 100 although higher levels are also possible. PMID:22925120
Crude trifluoroacetic acid extracts were prepared from different body parts of the forest ant, Formica polyctena Foerster, Hymenoptera, Formicidae, and the honeybee, Apis mellifera carnica Pollmann, Hymenoptera, Apidae. Extracts were prepurified by means of solidphaseextraction over reversed-phase...
Molecular imprinted polymers (MIPs) were prepared using rutin as the template, different reagents as the functional monomer and different reagents as the cross-linker by solution polymerization. Several parameters that would influence the performance of MIPs were investigated including the type of functional monomer (single or double) and cross-linker (single or double), and the molar ratio of the template, the functional monomer and the cross-linker. The optimum synthesis conditions of MIPs were found to be bi-monomers (acrylamide-co-2-vinyl pyridine, 3:1) and bi-crosslinker (ethylene glycol dimethacrylate-co-divinylbenzene, 3:1). The ratio of the template, the functional monomer and the cross-linker was found to be 1:6:20. MIPs synthesized under these conditions were filled into the cartridges as the adsorbents of solid-phaseextraction (SPE). A competition test was conducted to authenticate the selectivity and the specificity of molecularly imprinted solid-phaseextraction (MISPE) for rutin using the mixture solution of standard rutin and its structural analogs including quercetin, naringenin and kaempferol. Compared with purchased SPE including C(18), silica and PCX, MISPE showed better selectivity and enrichment property for rutin in the extracted solutions of Chinese medicinal plants than any others. The mean recoveries were 85.93% (RSD: 3.04%, n=3) for Saururus chinensis (Lour.) Bail and 88.61% (RSD: 3.36%, n=3) for Flos Sophorae, respectively, which indicated that the optimized rutin-MIPs possess the value of practical application. PMID:22483895
Amberlite XAD-7 resin was modified by room temperature ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate, [C6 mim]PF6) coating through a maceration method, gaining a new sort of hydrophobic adsorbent for the solidphaseextraction mini-column. Trace inorganic mercury in wastewater samples was preconcentrated and determined by flow injection online mini-column sampling coupled with spectrophotometric determination. In acid medium, dithizone was employed as chelator with cetyltrimethylammonium bromide (CTMAB) to form a red neutral mercury-dithizone complex, which could be extracted quantificationally by solidphaseextraction technique on the mini-column. Under the optimized conditions, the linearity and the detection limit of the proposed method were found to be 0.35 to 50.0 microg x L(-1) Hg2+ and 0.067 microg x L(-1) Hg2+, respectively. The enrichment factor of 25 times could be achieved with a 50 mL sampling volume and the developed procedure was successfully applied for the determination of mercury in the certified reference material (GSBZ50016-90) and the spiked dock wastewater samples with the recovery of 99%-103%. PMID:20828014
A new method is reported for the separation of aluminum ions [Al(III)] from interfering elements in parenteral and pharmaceutical solutions (PS) and bottled mineral water (BMW) samples, through solid-phaseextraction with 2-methyl-8-hydroxyquinoline (quinaldine) adsorbed onto activated silica gel. While the enrichment step of separated Al(III) was carried out by cloud point extraction (CPE) using 8-hydroxyquinoline as complexing reagent, the resulted complex was entrapped in a non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114). The enriched Al(III) in sample solutions were determined by spectrofluorometry (SPF) at lexcitation 370nm and lemission 510nm, and flame atomic absorption spectrometry (FAAS) for comparative purpose. The variables affecting the complexation and extrac...
We describe a method for solid-phaseextraction of biogenic thiols using multi-walled carbon nanotubes as adsorbent, and their subsequent determination via HPLC and fluorescence detection. The fluorogenic reagent N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl) iodoacetamide was applied to derivatizate the thiols. The type of eluent and its volume, the sample pH, extraction time and sample volume were optimized. The calibration curves of the thiols are linear in the range from 0.5 to 200?nM (for glutathione), 0.02 to 5?nM (for cysteine), and 2 to 500?nM (for acetylcysteine), and the correlation coefficients range between 0.9955 and 0.9997. The respective limits of detection are 20?pM, 4?pM and 80?pM (at an SNR of 3), and the limits of quatification are 67?pM, 13?pM, ...
Amberlite XAD-4 adsorber resin was modified with 8-hydroxy quinoline (Oxine) by equilibrating with methanol solution of the reagent and the modified resin was used as a support material for the solidphaseextraction and preconcentration of UO(2)(2+) from aqueous solution at pH between 4 and 5.5. Ten micrograms of uranium from 300 ml of aqueous phase could be quantitatively extracted in to 1g of the modified resin giving an enrichment of 200. Uranium collected in the column could be eluted out with methanol-HCl mixture and determined spectrophotometrically using arsenazo(III) as the chromogenic reagent. The preconcentration could be made selective to uranium by using EDTA as a masking agent for transition metal ions and Th(IV). PMID:18970579
The purpose of this study is to develop new analytical methods with good detection limit for toxic inorganic and organic compounds. The analyses of CN, organic acids, particulate materials in environmental samples have been done using several methods such as Ion Chromatography, SPE, SPME, GC/MS, GC/FID, SPLITT (split-flow thin cell fractionation) during the second year of this project. Advantage and disadvantage of several distillation method (by KS, JIS, EPA) for CN analysis in wastewater were investigated. As the results, we proposed new distillation apparatus for CN analysis, which was proved to be simpler, faster and to get better recovery than conventional apparatus. And ion chromatograph/pulsed amperometric detector (IC/PAD) system instead of colorimetry for CN detection was setup to solve matrix interference. And SPE(solidphaseextraction) and SPME (solidphase micro extraction) as liquid-solid extraction technique were applied to the analysis of phenols in wastewater. Optimum experimental conditions and factors influencing analytical results were determined. From these results, It could be concluded that C{sub 18} cartridge and polystyrene-divinylbenzene disk in SPE method, polyacrylate fiber in SPME were proper solidphaseadsorbent for phenol. Optimum conditions to analyze phenol derivatives simultaneously were established. Also, Continuous SPLITT (Split-flow thin cell) Fractionation (CSF) is a new preparative separation technique that is useful for fractionation of particulate and macromolecular materials. CSF is carried out in a thin ribbon-like channel equipped with two splitters at both inlet and outlet of the channel. In this work, we set up a new CSF system, and tested using polystyrene latex standard particles. And then we fractionated particles contained in air and underground water based on their sedimentation coefficients using CSF. (author). 27 refs., 13 tabs., 31 figs.
A molecularly imprinted polymer (MIP) for the purification of N(1),N(12)-bis(dihydrocaffeoyl)spermine (kukoamine A) was computationally designed and tested. The properties of the polymer were characterized. The protocol of the solidphaseextraction (SPE) of kukoamine A from potato peels was optimized. A HPLC-MS method for the quantification of kukoamine A was developed and used for all optimization studies. The capacity of the MIP in relation to kukoamine A from the potato peels extract was estimated at 54 mg/g of the polymer. The kukoamine A purified from potato extract using MIP was exceptionally pure (? 90%). Although the corresponding blank polymer was less selective than the MIP for the extraction of kukoamine A from the potato extract, it was shown that the blank polymer could be effectively used for the purification of the crude synthetic kukoamine (polymer capacity = 80 mg of kukoamine A/g of the adsorbent, kukoamine A purity ? 86%). Therefore, selective adsorbents could be computationally designed for other plant products, allowing their purification in quantities that would be sufficient for more detailed studies and potential practical applications. PMID:22142260
This study investigates the effects of different soil solidphases on the extracellular enzymatic hydrolysis of cellobiose to glucose. Montmorillonite, kaolinite, goethite and wood char did not adsorb cellobiose whereas they adsorbed 10, 70, 70, 99 % respectively of ?-glucosidase from Aspergillus...
This paper describes methods for solidphaseextraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in SolidPhaseExtraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.
Aquifer geochemistry was characterized at a field site in the Munshiganj district of Bangladesh where the groundwater is severely contaminated by As. Vertical profiles of aqueous and solidphase parameters were measured in a sandy deep aquifer (depth >150 m) below a thick confining clay (119 to 150 m), a sandy upper aquifer (3.5 to 119 m) above this confining layer, and a surficial clay layer (aquifer and near the top of the upper aquifer, aqueous As levels are low (aquifer. In contrast, solidphase As concentrations are uniformly low, rarely exceeding 2 ?g/g in the two sandy aquifers and never exceeding 10 ?g/g in the clay layers. Solidphase As is also similarly distributed among a variety of reservoirs in the deep and upper aquifer, including adsorbed As, As coprecipitated in solids leachable by mild acids and reductants, and As incorporated in silicates and other more recalcitrant phases. One notable difference among depths is that sorbed As loads, considered with respect to solidphase Fe extractable with 1 N HCl, 0.2 M oxalic acid, and a 0.5 M Ti(III)-citrate-EDTA solution, appear to be at capacity at depths where aqueous As is highest; this suggests that sorption limitations may, in part, explain the aqueous As depth profile at this site. Competition for sorption sites by silicate, phosphate, and carbonate oxyanions appear to sustain elevated aqueous As levels in the upper aquifer. Furthermore, geochemical profiles are consistent with the hypothesis that past or ongoing reductive dissolution of Fe(III) oxyhydroxides acts synergistically with competitive sorption to maintain elevated dissolved As levels in the upper aquifer. Microprobe data indicate substantial spatial comapping between As and Fe in both the upper and deep aquifer sediments, and microscopic observations reveal ubiquitous Fe coatings on most solidphases, including quartz, feldspars, and aluminosilicates. Extraction results and XRD analysis of density/magnetic separates suggest that these coatings may comprise predominantly Fe(II) and mixed valence Fe solids, although the presence of Fe(III) oxyhydroxides can not be ruled out. These data suggest As release may continue to be linked to dissolution processes targeting Fe, or Fe-rich, phases in these aquifers.
This paper demonstrates, for the first time, that adsorptive potential of bamboo charcoal for solid-phaseextraction of phthalate esters was investigated. The four phthalate esters, dimethyl phthalate (DMP), diethyl phthalate (DEP), butyl benzyl phthalate (BBP) and di-n-butyl phthalate (DBP), are quantitatively adsorbed on a bamboo charcoal packed cartridge, then the analytes retained on the cartridge are quantitatively desorbed with optimum amounts of acetone. Finally, the analytes in the eluant acetone are determined by high-performance liquid chromatography-ultraviolet detectior. Important parameters influencing the extraction efficiency, such as eluant and its volume, flow rate of sample, sample volume, pH, the amount of adsorbent and ionic strength were investigated and optimized in detail. Under the optimum conditions, the limits of detection were 0.35-0.43 microg/L for four phthalate esters. The proposed method has been applied to the analysis of rainwater and tap water samples. And satisfactory spiked recoveries were obtained in the range of 75.0-114.2%. All the results indicated that the bamboo charcoal has great potential as a novel adsorbent material for the enrichment and determination of phthalate esters in real environmental water samples. PMID:18243227
This research combined the use of selective extractions and X-ray spectroscopy to examine the fate of As and Cr in a podzolic soil contaminated by chromated copper arsenate (CCA). Iron was enriched in the upper 30 cm due to a previous one-time treatment of the soil with Fe(II). High oxalate-soluble Al concentrations in the Bs horizon of the soil and micro-XRD data indicated the presence of short-range ordered aluminosilicates (i.e., proto-imogolite allophane, PIA). In the surface layers, Cr, as Cr(III), was partitioned between a mixed Fe(III)/Cr(III) solidphase that formed upon the Fe(II) application (25--50%) and a recalcitrant phase (50--75%) likely consisting of organic material such as residual CCA-treated wood. Deeper in the profile Cr appeared to be largely in the form of extractable (hydr)oxides. Throughout the soil, As was present as As(V). In the surface layers a considerable fraction of As was also associated with a recalcitrant phase, probably CCA-treated woody debris, and the remainder was associated with (hydr)oxide-like solidphases. In the Bs horizon, however, XAS and XRF findings strongly pointed to the presence of PIA acting as an effective adsorbent for As. This research shows for the first time the relevance of PIA for the adsorption of As in natural soils.
Hemoglobin (Hb) modified magnetic nanocomposites are prepared by immobilization of Hb onto the surface of amino-functionalized Fe(3)O(4)@SiO(2) magnetic nanoparticles via covalent bonding with glutaraldehyde as cross-linker. The obtained nanocomposites are characterized with FT-IR, SEM, XRD and surface charge analysis. A direct solid-phaseextraction procedure for the isolation/separation of plasmid DNA using this nanocomposite as a novel adsorbent is thus developed. Some important experimental parameters governing the sorption efficiency, i.e., the pH of sample solution and the ionic strength, are investigated. The Hb modified magnetic nanocomposites provide a sorption capacity of 27.86mgg(-1) for DNA. By using 2.0mg of the nanocomposites as sorption medium and a suitable acidity of pH 6.1, a sorption efficiency of 93% is achieved for 25?gmL(-1) of DNA in 1.0mL of sample solution. Afterwards, the absorbed DNA could be readily recovered by using 1.0mL of Tris-HCl buffer (pH 8.9, 0.01molL(-1)), giving rise to a recovery of ca. 68.3%. The present solid-phasedextraction protocol is applied for the isolation of plasmid DNA from Escherichia coli culture, resulting in comparable yield and purity of plasmid DNA with respect to those obtained by using commercial kits. PMID:23141317
Solid-phaseextraction (SPE) procedures for cleanup and preconcentration followed by HPLC-UV method were investigated for the simultaneous determination of seven low-dosed pesticides in saline concentrates for hemodialysis. The target compounds were ametryn, desmetryn, prometryn, terbutryn, molinate, triallate and butylate. Polyethylene (three different types), teflon, polyurethane and polystyrene, in powder form, were investigated as adsorbents for solid-phaseextraction of the analytes from the saline samples. Quantification was performed at 222nm and the analytes were separated on a LiChrosorb RP-18 (5mum, 125mm x 4mm i.d.) column using gradient elution with water/acetonitrile as mobile phase. The duration each chromatographic run was 18min including column reconditioning. The efficiency of the different SPE substrates for retaining the analytes from the highly concentrated saline (HCS) samples was discussed. The best performance was achieved with polystyrene as SPE material considering preconcentration factor, precolumn clogging, reusing capability and similarity between the mobile phases for SPE and HPLC procedures. Analyte concentrations as low as 1mugL(-1) could be determined in spiked HCS samples after preconcentration on polystyrene SPE precolumns. Recoveries between 98.7 and 102.2% were obtained from commercial spiked samples. Detection limits ranging from 4.8 (for prometryn) to 46mugL(-1) (for butylate) were calculated (without preconcentration). The within-day relative standard deviations (n = 9) ranged from 2.3 to 4.8%. PMID:18969786
This research combined the use of selective extractions and x-ray spectroscopy to examine the fate of As and Cr in a podzolic soil contaminated by chromated copper arsenate (CCA). Iron was enriched in the upper 30 cm due to a previous one-time treatment of the soil with Fe(II). High oxalate-soluble Al concentrations in the Bs horizon of the soil and micro-XRD data indicated the presence of short-range ordered aluminosilicates (i.e. proto-imogolite allophane, PIA). In the surface layers, Cr, as Cr(III), was partitioned between a mixed Fe(III)/Cr(III) solidphase that formed upon the Fe(II) application (25-50%) and a recalcitrant phase (50-75%) likely consisting of organic material such as residual CCA-treated wood. Deeper in the profile Cr appeared to be largely in the form of extractable (hydr)oxides. Throughout the soil, As was present as As(V). In the surface layers a considerable fraction of As was also associated with a recalcitrant phase, probably CCA-treated woody debris, and the remainder was associated with (hydr)oxide-like solidphases. In the Bs horizon, however, XAS and XRF findings strongly pointed to the presence of PIA acting as an effective adsorbent for As. This research shows for the first time the relevance of PIA for the adsorption of As in natural soils.
The coupling of solid-phaseextraction (SPE) using bamboo charcoal (BC) as an adsorbent with a monolithic column-high performance liquid chromatography (MC-HPLC) method was developed for the high-efficiency enrichment and rapid determination of 16 polycyclic aromatic hydrocarbons (PAHs) in water. Key influence factors, such as the type and the volume of the elution solvent, and the flow rate and the volume of the sample loading, were optimized to obtain a high SPE recovery and extraction efficiency. BC as an SPE adsorbent presented a high extraction efficiency due to its large specific surface area and high adsorption capacity; MC as an HPLC column accelerated the separation within 8 min because of its high porosity, fast mass transfer, and low-pressure resistance. The calibration curves for the PAHs extracted were linear in the range of 0.2-15 µg/L, with the correlation coefficients (r(2)) between 0.9970-0.9999. This method attained good precisions (relative standard deviation, RSD) from 3.5 to 10.9% for the standard PAHs I aqueous solutions at 5 µg/L; the method recoveries ranged in 52.6-121.6% for real spiked river water samples with 0.4 and 4 µg/L. The limits of detection (LODs, S/N = 3) of the method were determined from 11 and 87 ng/L. The developed method was demonstrated to be applicable for the rapid and sensitive determination of 16 PAHs in real environmental water samples. PMID:22586244
In this paper, a graphene-based Fe(3)O(4) magnetic nanoparticles (G-Fe(3)O(4) MNPs) was used as the adsorbent for the magnetic solid-phaseextraction of some triazine herbicides (atrazine, prometon, propazine and prometryn) in environmental water samples followed by high performance liquid chromatography-diode array detection (HPLC-DAD). After the extraction, the adsorbent can be conveniently separated from the aqueous samples by an external magnet. The main factors influencing the extraction efficiency including the amount of the MNPs, the extraction time, the pH of sample solution, and desorption conditions were studied and optimized. Under the optimized experimental conditions, a good linearity was observed in the range of 0.1-50.0 ng mL(-1) for all the analytes, with the correlation coefficients (r) ranging from 0.9996 to 0.9999. The limits of detection of the method ranged between 0.025 and 0.040 ng mL(-1). Good reproducibility was obtained with the relative standard deviations below 5.2%. The developed method was applied to the analysis of the triazine herbicides in different water samples (lake, river and reservoir). The recoveries of the method were in the range between 89.0% and 96.2%. PMID:22093359
A new approach to performing extraction and preconcentration employing functionalized magnetic nanoparticles for the determination of trace metals is presented. Alumina-coated iron oxide nanoparticles were synthesized and used as the solid support. The nanoparticles were functionalized with sodium dodecyl sulfate and used as adsorbents for solidphaseextraction of the analyte. Extraction, elution, and detection procedures were performed sequentially in the sequential injection lab-on-valve (SI-LOV) system followed by electrothermal atomic absorption spectrometry (ETAAS). Mixtures of hydrophobic analytes were successfully extracted from solution using the synthesized magnetic adsorbents. The potential use of the established scheme was demonstrated by taking cobalt as a model analyte. Under the optimal conditions, the calibration curve showed an excellent linearity in the concentration range of 0.01-5 ?g L(-1), and the relative standard deviation was 2.8% at the 0.5 ?g L(-1) level (n=11). The limit of detection was 6 ng L(-1) with a sampling frequency of 18 h(-1). The present method has been successfully applied to cobalt determination in water samples and two certified reference materials. PMID:22200313
A rapid, specific, and sensitive method has been developed using molecularly imprinted polymers (MIPs) as solid-phaseextraction sorbents for extraction of trace tetracycline antibiotics (TCs) in foodstuffs. MIPs were prepared by precipitation polymerization using tetracycline as the template. Under the optimal condition, the imprinting factors for MIPs were 4.1 (oxytetracycline), 7.0 (tetracycline), 7.4 (chlortetracycline), 7.7 (doxycycline), respectively. Furthermore, the performance of MIPs as solid-phaseextraction sorbents was evaluated and high extraction efficiency of molecularly imprinted solid-phaseextraction (MISPE) procedure was demonstrated. Compared with commercial sorbents, MISPE gave a better cleanup efficiency than C18 cartridge and a higher recovery than Oasis HLB cartrid...
Microwave-assisted thermal desorption (MAD) coupled to headspace solid-phase microextraction (HS-SPME) has been studied for in-situ, one-step, sample preparation for PAHs collected on XAD-2 adsorbent, before gas chromatography with mass spectrometric detection. The PAHs on XAD-2 were desorbed into the extraction solution, evaporated into the headspace by use of microwave irradiation, and absorbed directly on a solid-phase microextraction fiber in the headspace. After desorption from the SPME fiber in the hot GC injection port, PAHs were analyzed by GC-MS. Conditions affecting extraction efficiency, for example extraction solution, addition of salt, stirring speed, SPME fiber coating, sampling temperature, microwave power and irradiation time, and desorption conditions were investigated. Experimental results indicated that extraction of 275 mg XAD-2, containing 10-200 ng PAHs, with 10-mL ethylene glycol-1 mol L{sup -1} NaCl solution, 7:3, by irradiation with 120 W for 40 min (the same as the extraction time), and collection with a PDMS-DVB fiber at 35 C, resulted in the best extraction efficiency. Recovery was more than 80% and RSD was less than 14%. Optimum desorption was achieved by heating at 290 C for 5 min. Detection limits varied from 0.02 to 1.0 ng for different PAHs. A real sample was obtained by using XAD-2 to collect smoke from indoor burning of joss sticks. The amounts of PAHs measured varied from 0.795 to 2.53 ng. The method is a simple and rapid procedure for determination of PAHs on XAD-2 absorbent, and is free from toxic organic solvents. (orig.)
An accurate and sensitive method, combining soxhlet extraction, solidphase-extraction and capillary gas chromatography is described for the quantitative determination of one triterpene (lupeol) and three sterols (stigmasterol, campesterol and beta-sitosterol) and the detection of another triterpene...
Sep 15, 2009 ... biomarkers from proteins and peptides sequestered in soils and .... 2001] or solid -phaseextraction (SPE) concentration of an aqueous extract. ... our knowledge of the range of conditions suitable for prebiotic synthesis and ...
Solidphase microextraction (SPME) has revolutionized the way samples are extracted, enabling rapid, automated, and solventless extraction of many different sample types, including air, water, soil, and biological samples. As such, SPME is widely used for environmental, food, fo...
The allelopathic activity of the aquatic macrophyte, Stratiotes aloides, was determined with laboratory experiments. Active compounds exuded in the medium or present in plant tissue were extracted using standard procedures and solidphaseextraction (SPE). The activity towards various cyanobacteria ...
A new tris(2-aminoethyl) amine (TREN) functionalized silica gel (SG-TREN) was prepared and investigated for selective solid-phaseextraction (SPE) of trace Cr(III), Cd(II) and Pb(II) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Identification of the surface modification was characterized and performed on the basis of FT-IR. The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 4, the maximum adsorption capacity of Cr(III), Cd(II) and Pb(II) onto the SG-TREN were 32.72, 36.42 and 64.61mgg-1, respectively. The adsorbed metal ions were quantitatively eluted by 5mL of 0.1molL-1 HCl. Common coexi...
Capillary-channeled polymer (C-CP) fibers are employed in a micropipette tip format to affect a stationary phase for the solidphaseextraction (SPE) of proteins from buffer solutions prior to MALDI-MS analysis. Proteins readily adsorb to the polypropylene (PP) C-CP fibers while buffer species are easily washed off the tips using DI-H2O. Elution of the solutes is achieved with an aliquot of 50:50 ACN:H2O, which is compatible with the subsequent spotting on the MALDI target with the matrix solution. Lysozyme and cytochrome c are used as test species, with a primary buffer composition of 100 mM Tris?HCl. In this case, direct MALDI-MS produces no discernible protein signals. SPE on the C-CP fibers yields high fidelity mass spectra for 1 ?L sample volumes. Limits of detection for cytochrome c ...
Hemoglobin (Hb) modified magnetic nanocomposites are prepared by immobilization of Hb onto the surface of amino-functionalized Fe3O4@SiO2 magnetic nanoparticles via covalent bonding with glutaraldehyde as cross-linker. The obtained nanocomposites are characterized with FT-IR, SEM, XRD and surface charge analysis. A direct solid-phaseextraction procedure for the isolation/separation of plasmid DNA using this nanocomposite as a novel adsorbent is thus developed. Some important experimental parameters governing the sorption efficiency, i.e., the pH of sample solution and the ionic strength, are investigated. The Hb modified magnetic nanocomposites provide a sorption capacity of 27.86mgg?1 for DNA. By using 2.0mg of the nanocomposites as sorption medium and a suitable acidity of pH 6....
A simple and robust method using solid-phaseextraction (SPE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of 14 drugs of abuse and their metabolites (cocainics, amphetamine-like compounds, cannabinoids, and opiates) in surface waters has been developed. Seven SPE adsorbents (Oasis HLB, Oasis MCX, Oasis Wax, Supelselect HLB, Strata-X, Strata-XCW), amount of sorbent bed, water volume, and pH were investigated. The highest recoveries, as well as the simplest protocol, were obtained for Oasis HLB cartridges (6?mL/200?mg) using 250?mL of water. The proposed method was linear in a concentration range from 0.03?6 to 300?60,000?ng/L depending on the compound, with correlation coefficients higher than 0.998. Matrix effects have been studied in su...
Reactive volatile organic compounds (VOCs) are known to affect atmospheric chemistry. Biogenic VOCs (BVOCs) have a significant impact on regional air quality due to their large emission rates and high reactivities. Diterpenes (most particularly, kaur-16-ene) were detected in all of the 205 enclosure air samples collected over multiple seasons at two different sites from Cryptomeria japonica and Chamaecyparis obtusa trees, the dominant coniferous trees in Japan,. The emission rate of kaur-16-ene, was determined to be from 0.01 to 7.1 ?g dwg(-1) h(-1) (average: 0.61 ?g dwg(-1) h(-1)) employing branch enclosure measurements using adsorbent sampling followed by solidphase-liquid extraction techniques. The emission rate was comparable to that of monoterpenes, which is known major BVOC emissions, collected from the same branches. In addition, total emission of kaur-16-ene at 30°C was estimated to exceed that of total anthropogenic VOC emissions. PMID:22342335
Abstract in english A dynamic mathematical model, simulation and computer control of a Continuous Affinity Recycle Extraction (CARE) process, a protein purification technique based on protein adsorption on solid-phaseadsorbents is described in this work. This process, consisting of three reactors, is a multivariable process with considerable time delay in the on-line analyses of the controlled variable. An advanced predictive control configuration, specifically the Dynamic Matrix Control (D (more) MC), was applied. The DMC algorithm was applied in process schemes where the aim was to maintain constant the enzyme concentration in the outlet of the third reactor. The performance of the DMC controller was analyzed in the feed-flow disturbances and the results are presented.
A novel and effective dispersive solid-phaseextraction (dSPE) procedure with rapid magnetic separation using ethylenediamine-functionalized magnetic polymer as an adsorbent was developed. The new procedure had excellent clean-up ability for the selective removal of the matrix in red wine. An accurate, simple, and rapid analytical method using ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) for the simultaneous determination of nine food additives (i.e., acesulfame, saccharin, sodium cyclamate, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid, and neotame) in red wine was also used and validated. Recoveries ranging from 78.5% to 99.2% with relative standard deviations ranging from 0.46% to 6.3% were obtained using the new method. All ta...
Magnetic solid-phaseextraction based on coated nano-magnets Fe(3)O(4) was applied for the preconcentration of four polycyclic aromatic hydrocarbons (PAHs; anthracene, phenanthrene, fluorine, and pyrene) in environmental water samples prior to simultaneous spectrophotometric determination using multivariate calibration method. Magnetic nanoparticles, carrying target metals, were easily separated from the aqueous solution by applying an external magnetic field so, no filtration or centrifugation was necessary. After elution of the adsorbed PAHs, the concentration of PAHs was determined spectrophotometrically with the aid of a new and efficient multivariate spectral analysis base on principal component analysis-projection pursuit regression, without separation of analytes. The obtained results revealed that using projection pursuit regression as a flexible modeling approach improves the predictive quality of the developed models compared with partial least squares and least squares support vector machine methods. The method was used to determine four PAHs in environmental water samples. PMID:22684809
In this paper, 1-hexadecyl-3-methylimidazolium bromide (C16mimBr)-coated Fe3O4 magnetic nanoparticles (NPs) as an adsorbent of mixed hemimicelles solid-phaseextraction was investigated for the preconcentration of two chlorophenols (CPs) in environmental water samples prior to HPLC with UV detection at 285nm. The high surface area and excellent adsorption capacity of the Fe3O4 NPs after modification with C16mimBr were utilized adequately in the SPE process. By the rapid isolation of Fe3O4 NPs through placing a strong magnet on the bottom of beaker, the time-consuming preconcentration process of loading large volume sample in conventional SPE method with a column can be avoided. A comprehensive study of the adsorption conditions such as the zeta-potential of Fe3O4 NPs, added amounts of C16m...
The magnetic mixed hemimicelles solid-phaseextraction (MMHSPE), based on the adsorption of cation surfactant octadecyltrimethylammonium bromide (OTMABr) onto magnetite nanoparticles (Fe3O4 NPs) to form mixed hemimicelles, was proposed for the preconcentration of several sulfonamides (SAs) compounds including sulfamethoxazole (SMX), sulfamethoxydiazine (SMD), sulfadimethoxine (SDM) and sulfaquinoxaline (SQX) from environmental water samples. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of OTMABr-coated Fe3O4 NPs with an adscititious magnet. Mixed hemimicelles formed on the surface of Fe3O4 NPs by OTMABr showed great adsorptive tendency towards analytes. The OTMABr-coated Fe3O4 NPs adsorbents wer...
We report on a novel and selective method for the preconcentration and determination of Cr(VI) in aqueous samples. Cr(VI) is adsorbed - in a ?batch mode? - on multiwalled carbon nanotubes covered with Aliquat 336 and then determined directly, i.e., on the solid, by X-ray fluorescence spectrometry. This reduces the number of reagents and minimizes sample handling. The method combines the advantages of solid-phaseextraction with the benefits of the XRF method in that the large areas required by the carbon nanotubes make them a promising solid sorbent for preconcentration. The enrichment factor was calculated after considering that the thin film obtained from the 10?mL solution of 1?mg?L?1 of Cr(VI) has a real thickness of 0.04?mm and a final diameter of 16.7?mm, so that the volume deposited...
A solidphaseextraction method has been developed for the determination of copper, nickel and zinc ions in natural water samples. This method is based on the adsorption of copper, nickel and zinc on multiwalled carbon nanotubes (MWCNTs) impregnated with di-(2-ethyl hexyl phosphoric acid) (D2EHPA) and tri-n-octyl phosphine oxide (TOPO). The influence of parameters such as pH of the aqueous solution, amount of adsorbent, flow rates of the sample and eluent, matrix effects and D2EHPA-TOPO concentration have been investigated. Desorption studies have been carried out with 2molL^-^1 HNO3. The copper, nickel and zinc concentrations were determined by flame atomic absorption spectrometry. The results indicated that the maximum adsorption of copper, nickel and zinc is at pH 5.0 with 500mg of MWCN...
Blood represents a convenient diagnostic specimen for clinical analysis. Serum metabolites and peptides have the potential to serve as reliable indicators of progression from a normal to a diseased state. However, the presence of salts, lipids and high concentrations of protein in blood serum can adversely affect its mass spectrometric profiling, as all of these moieties can hinder the ionisation and detection of diagnostic biomarkers. Several pre-fractionation strategies using chromatographic adsorbents have been employed to desalt samples and remove abundant proteins such as albumin and immunoglobulin. As an alternative to multi-stage fractionation chromatography, we describe in this practical review the adaptation and validation of a simple and fast solid-phaseextraction technique usin...
Summary A new and simple solid-phaseextraction method for the determination of trace levels of sunset yellow has been developed on Diaion HP 2MG column system. The adsorbed sunset yellow on the resin was eluted with 3-mL of methanol and determined by UV-Vis spectrophotometry at 484-nm. Various experimental parameters such as pH, amount of sunset yellow, flow rates of sample and eluent solutions, resin amount, sample volumes, etc. were investigated. The influences of some alkali, alkali earth and transition metals on the recoveries of sunset yellow were investigated. The recovery values for sunset yellow were higher than 95%. Preconcentration factor was found as 150. The detection limit (three sigma) of the reagent blank for sunset yellow was 5.2-g-L-1. The relative standard deviations (RS...
A simple and effective method has been presented for the preconcentration of uranium by solidphaseextraction. For this purpose arsenazo(III) supported on naphthalene-methyltrioctylammonium chloride was used as an adsorbent and uranium solution at pH 3.5 with flow rate of 1 mLmin-1 was passed through the column. Therefore, uranium-arsenazo(III) complex was formed onto column. Uranium was quantitatively eluted with 5 mL of a 0.1% ammonium tetraphenylborate and determined by spectrophotometric method at 652 nm. Several parameters such as pH, amount of reagents, sample volume, etc. were investigated. The effect of diverse ions on the preconcentration has also been studied and the optimized conditions developed have been utilized for the trace determination of uranium. A preconcentration fact...
This paper shows an analytical methodology based on solid-phaseextraction by XAD-2 adsorbent and gas chromatography (GC) coupled with nitrogen?phosphorus (NPD) and ion-trap mass spectrometry detectors (ITMS) in negative chemical ionization (NCI) mode analyses for investigating organophosphorus pesticides (OPs) at trace levels (in nanograms per cubic meter) in the atmosphere: in particular, we set up a procedure for analyzing 38 OPs. For the analytical methodology linearity responses have been obtained in GC-NPD (r?>?0.9982) and GC-NCI/ITMS (r?>?0.9974) in a large linearity range (0.10?500 pg ?L?1 in both cases) whereas the limits of detection range between 0.01 and 0.03 pg ?L?1 in both the techniques with a relative standard deviation (RSD) below 9.0 in both cases. Particular attention ha...
An on-line solidphase micro-column extraction and determination system for trace Cd and Pb in nuclear fuel grade uranium compounds was established. The preconcentration of trace elements Cd and Pb from uranium compounds was achieved by adsorbing Cd and Pb on CL-7301 resin in hydroiodic acid media, while the uranyl ion passed through. The method coupled with flame atomic absorption spectrometry (FAAS) was applied to analysis trace Cd and Pb in real samples. The preconcentration factors obtained by this method were 320 and 180 each for Cd and Pb, respectively. Under the optimized conditions, the detection limits corresponding to three times the standard deviation of the blank were found to be 0.13 ng?mL?1 and 0.37 ng?mL?1 for Cd and Pb, respectively. The relative standard deviation (RSD) an...
Multi-walled carbon nanotubes (MWCNTs) were evaluated as potential adsorbents for miniaturized solid-phaseextraction coupled to liquid chromatography. The adsorption capacity of this sorbent was applied to assess the speciation of four cobalamins representing the various forms of vitamin B12. The preconcentration on the MWCNTs was based on the retention of analytes by introducing the sample online into the mini-column system. Dimethyl sulfoxide was used to elute the retained vitamins for liquid chromatographic analysis. The experimental conditions of the continuous flow device, which affect the enrichment procedure, such as the type and amount of nanotubes, the volume, pH and flow rate of the sample solution, and the eluent and its volume, were optimized. For detection purposes, a diode a...
We report on a novel and selective method for the preconcentration and determination of Cr(VI) in aqueous samples. Cr(VI) is adsorbed - in a ?batch mode? - on multiwalled carbon nanotubes covered with Aliquat 336 and then determined directly, i.e., on the solid, by X-ray fluorescence spectrometry. This reduces the number of reagents and minimizes sample handling. The method combines the advantages of solid-phaseextraction with the benefits of the XRF method in that the large areas required by the carbon nanotubes make them a promising solid sorbent for preconcentration. The enrichment factor was calculated after considering that the thin film obtained from the 10 mL solution of 1 mg?L?1 of Cr(VI) has a real thickness of 0.04 mm and a final diameter of 16.7 mm, so that the volume deposited...
Summary We describe an automatic method to detect formaldehyde (FA) in some fermented foods. This method is based on derivatisation with 2,2,2-trifluoroethylhydrazine (TFEH) and consecutive headspace solid-phase micro-extraction and gas chromatography-mass spectrometry. FA in food reacted for 30-min at 40-C with 2,2,2-TFEH in a headspace vial, and the formed FA-TFEH derivative was simultaneously vaporised and adsorbed on 85-m carboxen-polydimethylsiloxane. Under the established condition, the limit of detection was 0.1-g-kg-1 by using 1.0-g solid food and 1.0-mL liquid food, and the relative standard deviation was less than 10% at FA concentrations between 0.050 and 0.500-mg-kg-1. The concentrations of FA in several traditional Korean foods including gimchi, watery radish gimchi, soybean p...
Abstract in english Solidphase microextraction (SPME) was applied to the analysis of a selected group of non halogenated solvents -all of them classified as volatile organic compounds (VOCs)- that may be present in diverse industrial wastewaters. Two different fibres (100-PDMS and 85-PA) were selected as SPME adsorbents. The extracted volatile organic compounds were analysed by high resolution gas chromatography coupled to mass spectrometry (GC-MS), following the EPA method 624. Calibration (more) curves and method deletion limits obtained for these solvents using the two SPME fibres are reported. The 100-PDMS fibre provided better sensitivity, but the saturation was reached at a lower concentration than 85-PA fibre. The first fibre (100-PDMS) was applied to the analysis of several textile wastewaters. The method detection limits obtained with this fibre were: 0.1-0.3 ?/L for ethylbenzene m-xylene p-xylene toluene and diisobutyl ketone. In addition SPME and Headspace (HS) detection limits were compared.
Metformin is one of the most common adulterants found in anti-diabetic dietary supplements and herbal medicines. An analytical method based on hydrophilic interaction chromatography (HILIC)/tandem mass spectrometry was developed and validated for the determination of metformin in dietary supplements and herbal medicines. Sample preparation involved solidphaseextraction of the analyte using Plexa PCX cartridges, and cleanup by a primary-secondary amine (PSA) adsorbent for minimization of the matrix effect. Chromatographic separation was performed on a HILIC column using a mixture of 0.025mol/L ammonium formate (pH 3) and acetonitrile (18:82, v/v) as the mobile phase at flow rate of 0.25mL/min. The method was validated in four matrices (capsules, honeyed pills, tablets and oral solutions)....
A simple approach has been developed for the solidphaseextraction of chromium(VI) based on the adsorption of its ion-association complex with cetyltrimethylammoniumbromide (CTABr) on an alumina column. The effect of various parameters such as acidity, stability of the column, sample volume, effect of diverse ions, etc. have been studied in detail. The adsorbed complex could be eluted using sodium hydroxide and the concentration of chromium has been established using visible spectrophotometry after complexation with diphenyl carbazide. The calibration graph was linear in the range 0-0.5mgmL-1 chromium(VI) with a detection limit of 5mgL-1. A highest preconcentration factor of 25 could be obtained for 250mL sample volume. The data from the column studies were also studied using the Thomas m...
It has been indicated that hydrophilic solid powder to which aqueous solution of a novel dehydrocondensing reagent DMT-MM is adsorbed becomes a simple solid-phase dehydrocondensing reagent of low cost. Reaction in a liquid–liquid biphasic system on the surface of a solidphase with a large area was accelerated by suspending this powder in a dichloromethane solution of a carboxylic acid and an amine to be condensed. The reaction was rapid with a high yield despite the heterogeneity of the system. Like general solid-phase reagents, a hydrophobic carboxamide alone could be isolated at a relatively high purity only by filtration of the resulting suspension of reaction mixture.
In the present work, a new method was established by applying solid-phaseextraction (SPE) to preconcentrate and separate polymeric aluminum (Al) and using ICP-AES to determine the polymeric Al, the total monomeric Al, and the total Al in soil extracts, respectively. A modified resin was prepared with impregnated 8-hydroxyquinoline-5-sulfoxinate (HQS) on the anion-exchange resin. It has good recognition ability for Al fractions, compared to the commonly used cation ion-exchange resin, which has a better ability to adsorb cations and a weak ability to recognize detailed Al species. The optimum conditions for Al fractionation sorption, elution and separation and the interference of foreign ions were studied with the prepared resin by continuous column and batch procedures. Monomeric Al was bound to Pyrocathecol Violet (PCV) at pH 6.2, whereas the polymeric Al species did not react with PCV for at least 15 min. Because a stable complex of Al-PCV was not absorbed on the HQS modified resin, the polymeric Al could be preconcentrated on-line by the HQS-modified resin. The adsorbed polymeric Al was eluted with 3 mL of 3 mol L-1 of HCl, and then detected by ICP-AES. The method has been applied to directly determine polymeric Al in soil extracts with high selectivity as well as a high preconcentration factor. It gives a limit of detection of 0.6 ng mL-1 with a relative standard deviation of less than 5.7% (n = 5, 0.24 ?g mL-1 Al).
Radiation induced degradation of polymeric materials occurs via numerous, simultaneous, competing chemical reactions. Though degradation is typically found to be linear in adsorbed dose, some silicone materials exhibit non-linear dose dependence due to dose dependent dominant degradation pathways. We have characterized the effects of radiative and thermal degradation on a model filled-PDMS system, Sylgard 184 (commonly used as an electronic encapsulant and in biomedical applications), using traditional mechanical testing, NMR spectroscopy, and sample headspace analysis using SolidPhase Micro-Extraction (SPME) followed by Gas Chromatography/Mass Spectrometry (GC/MS). The mechanical data and {sup 1}H spin-echo NMR indicated that radiation exposure leads to predominantly crosslinking over the cumulative dose range studies (0 to 250 kGray) with a rate roughly linear with dose. {sup 1}H Multiple Quantum NMR detected a bimodal distribution in the network structure, as expected by the proposed structure of Sylgard 184. The MQ-NMR further indicated that the radiation induced structural changes were not linear in adsorbed dose and competing chain scission mechanisms contribute more largely to the overall degradation process in the range of 50 -100 kGray (though crosslinking still dominates). The SPME-GC/MS data were analyzed using Principal Component Analysis (PCA), which identified subtle changes in the distributions of degradation products (the cyclic siloxanes and other components of the material) as a function of age that provide insight into the dominant degradation pathways at low and high adsorbed dose.
The labile iron(II) and iron(III) species are complexed directly in the sample solution with 1,10 phenanthroline and ferron (8-hydroxy-7-iodoquinoline-5-sulfonic acid), respectively. The complexes thus formed are mutually adsorbed and separated by solidphaseextraction. The direct determination of iron(III) and iron(II) species with flame atomic absorption spectrometry (FAAS) follows the elution of the iron(III)-ferron complex adsorbed by an anion-exchange and an iron(II)-phenanthroline complex adsorbed by a non-polar RP-18 phase. In the case of indirect determination, the iron(II)-phenanthroline complex that passes through the anion-exchange phase, is measured, and the content of iron(III) is calculated by the difference of the iron(II) and the total iron content. A direct determination with this method has been applied to the iron species analysis in wine samples and the results are compared with those obtained for the determination with adsorptive stripping voltammetry (ASV) as reference method. (orig.) With 4 figs., 3 tabs.
An on-line flow system was used to develop a selective and efficient on-line sorbent extraction preconcentration system for cadmium. The method is based on adsorption of cadmium ions onto the activated carbon modified with methyl thymol blue. Then the adsorbed ions were washed using 0.5 M HNO{sub 3} and the eluent was used to determine the Cd(II) ions using flame atomic absorption spectrometry. The results obtained show that the modified activated carbon has the greatest adsorption capacity of 80 {mu}g of Cd(II) per 1.0 g of the solidphase. The optimal pH value for the quantitative preconcentration was 9.0 and full desorption is achieved by using 0.5 M HNO{sub 3} solution. It is established that the solidphase can be used repeatedly without a considerable adsorption capacity loss. The detection limit was less than 1 ng mL{sup -1} Cd(II), with an enrichment factor of 1000. The calibration graph was linear in the range of 1-2000 ng mL{sup -1} Cd(II). The developed method has been applied to the determination of trace cadmium (II) in water samples and in the following reference materials: sewage sludge (CRM144R), and sea water (CASS.4) with satisfactory results. The accuracy was assessed through recovery experiments.
The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography–mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solidphase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solidphase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss. PMID:22110044
The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography-mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solidphase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solidphase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss. PMID:23175670
A method is described for extracting fluoride ions from a nuclear fuel solution which comprises treating said solution with a solidphase from hydrated silica, such as silica gel and/or silicic acid, to bind the fluorine to the silicium. The solidphase is then separated from said solution.
In order to model transport of dissolved ions in subsurface environments, one should understand how these ions interact with solidphaseadsorbents. Our primary goal has been investigating the reaction mechanisms which affect microcontaminant partitioning between aqueous solutions and solidphaseadsorbents, using goethite ({alpha}-FeOOH) as a model adsorbent. Cylindrical internal reflection -- Fourier transform infrared (CIR-FTIR) spectroscopy has been developed as the primary technique for this study. Wet chemical adsorption studies, acoustophoresis and electrophoretic mobility have been used to obtain supporting information as needed. Phenol and o-nitrophenol did not adsorb to goethite. Benzoate, phthalate and p-hydroxybenzoate all adsorbed via a bidentate mechanism to two adjacent iron atoms, while salicylate and 2,4-dihydroxybenzoate formed a chelate complex to single iron atoms. Phosphate adsorption was predominately bidentate.
A magnetic solid-phaseextraction (MSPE) method combined with capillary electrophoresis for the simultaneous determination of seven quinolones (QNs) (danofloxacin, ciprofloxacin, marbofloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine), using (S)-(+)-6-methoxy-?-methyl-2-naphthaleneacetic acid as internal standard, in milk samples was developed. The variables involved in the preconcentration magnetic procedure were: the composition of the magnetic support composition, the sample pH, and the weight of magnetic adsorbent used. The variables were optimized using a simplex-lattice design. Different magnetite covered with octyl-phenyl silica adsorbents were synthesized by varying the molar ratio of phenyltrimethylsilane and octyltrimethoxysilane; the solids were evaluated for QN preconcentration. Under optimal conditions, a linear range was obtained from 27 to 1000 ?g L(-1) with limits of detection ranging from 9 to 12 ?g L(-1) for the seven QNs. The absolute recoveries of the seven QNs at three different spiked levels (40, 150, and 400 ?g L(-1) ) ranged from 74% to 98% with a relative standard deviation less than 10% in all cases. The proposed method was applied to analyze 20 whole milk samples of different brands. All samples were positive for the presence of QN residues; in some cases, extract dilution was required. The concentrations found are in the range from 31.1 to 5047.3 ?g L(-1) . Marbofloxacin was the most frequently found. The method proposed offers advantages in terms of simplicity, sensitivity, efficiency, cost, and analysis time making it an alternative for the analysis of QNs in whole milk samples. PMID:22806471
Four new ionic liquids (IL) were prepared and bonded onto 5-microm silica particles for use as adsorbent in solid-phase microextraction (SPME). Two ILs contained styrene units that allowed for polymerization and higher carbon content of the bonded silica particles. Two polymeric ILs differing by their anion were used to prepare two SPME fibers that were used in both headspace and immersion extractions and compared to commercial fibers. In both sets of experiments, ethyl acetate was used as an internal standard to take into account adsorbent volume differences between the fibers. The polymeric IL fibers are very efficient in headspace SPME for short-chain alcohols. Immersion SPME also can be used with the IL fibers for short-chain alcohols as well as for polar and basic amines that can be extracted at pH 11 without damage to the IL-bonded silica particles. The sensitivities of the two IL fibers differing by the anion were similar. Their efficacy compares favorably to that of commercial fibers for polar analytes. The mechanical strength and durability of the polymeric IL fibers were excellent. PMID:19924406
This study compared four extraction methods for the simultaneous determination of tetracyclines, macrolides, quinolones, sulphonamides and anthelmintics (including benzimidazoles and avermectins) in eggs by ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Solvent extraction, solid-phaseextraction (SPE), matrix solid-phase dispersion (MSPD) and modified QuEChERS procedure were compared in terms of recovery and number of veterinary drugs extracted. The solvent extraction procedure with a clean-up step provided better results than the other tested procedures. The QuEChERS procedure was simpler and faster, but extracted fewer compounds than solvent extraction. MSPD did not extract tetracyclines and quinolones, whereas macrolides and tetracyclines we...
In this study, the new C(18)-functionalized ultrafine magnetic silica nanoparticles (C(18)-UMS NPs) were successfully synthesized and applied for extraction of sudan dyes in water samples based on the magnetic solid-phaseextraction (MSPE). The extraction and concentration were carried out in one step by blending C(18)-UMS NPs and water samples. The sudan dyes adsorbed C(18)-UMS NPs were isolated from the matrix easily with an external magnetic field. After desorption the quantitation of sudan dyes was done by ultra fast liquid chromatography (UFLC). Satisfactory extraction recovery can be obtained with only 50 mg C(18)-UMS NPs. The effects of experimental parameters, including the amount of the nanoparticles, extraction time, pH value, desorption solvent, volume of desorption solvent and desorption time were investigated. The limits of detection for sudan I, II, III and IV were 0.066, 0.070, 0.12 and 0.12 ng mL(-1), respectively. Recoveries obtained by analyzing the six spiked water samples were between 68% and 103%. PMID:22284457
In this study, the capability of the prepared polyaniline-coated Fe(3) O(4) nanoparticles for magnetic solid-phaseextraction of three parabens from environmental wastewater, cream, and toothpaste samples is presented. Synthesized Fe(3) O(4) nanoparticles were coated with sulfate-doped polyaniline via polymerization of aniline in the presence of Fe(3) O(4) nanoparticles and sulfuric acid. Here, polyaniline-coated Fe(3) O(4) nanoparticles are presented as anion exchange sorbent, which extract anionic form of parabens via anion exchange with dopant of polyaniline. The experimental conditions affecting extraction efficiency were further studied and optimized. The experimental results showed that maximum extraction efficiency can be obtained at 70 mL sample solution of pH 8, extraction and desorption times of 2 and 1 min, respectively, 100 ?L of 3% (v/v) acetic acid in acetonitrile as eluent, and 100 mg of the adsorbent. Under these conditions, the linear dynamic ranges were 0.5-100 ?g/L with good correlation coefficients (0.998-0.999). The detection limits were in the range of 0.3-0.4 ?g/L and the relative standard deviations were less than 2.4 (n = 5) for the three parabens. Finally, this fast and efficient method was further employed for determination of target analytes in cream, toothpaste, and environmental wastewater samples and satisfactory results were obtained. PMID:22833522
Abstract in spanish A través del método de equilibrio batch se comparó la adsorción de las catecolaminas Dopamina (DA), Noradrenalina (NA) y Adrenalina (A), y de los metabolitos ácido dihidroxifenilacético (Dopac) y ácido indolacético (5- HIAA) en las fases sólidas octadecil (C18) hidrofóbica, diol (C Diol) hidrofílica y de intercambio catiónico débil (WCX). En la fase sólida WCX a pH 4,0 se observó un 78% de adsorción de catecolaminas y 68% de adsorción de Dopac. Las isoter (more) mas de adsorción de las catecolaminas en la fase WCX son de tipo Langmuir. La adrenalina tiene mayor afinidad que la dopamina por la fase WCX a pH 4,0 y la dopamina mayor afinidad que el Dopac y éste es coadsorbido sobre las catecolaminas adsorbidas en la fase WCX. Un ensayo con solventes orgánicos demostró que el tolueno extrajo selectivamente de una mezcla sintética el Dopac y el 5-HIAA coadsorbido, mientras que en una muestra de tejido cerebral de ratas experimentales fueron extraídos el Dopac y el ácido homovanílico (HVA). Estos resultados sirvieron para proponer un paso adicional de extracción con solventes orgánicos para la separación de metabolitos ácidos durante la extracción en fase sólida (EFS) en el análisis de catecolaminas. Abstract in english The adsorptions of Dopamine (DA), Noradrenaline (NA), and Adrenaline (A) catecholamines were compared by using the batch equilibrium method, as well as those of the dihydroxyphenylacetic acid (Dopac) and indolacetic acid (5-HIAA) metabolites on the hydrophobic octadecyl (C18), hydrophilic diol (C Diol) and weak cation exchange (WCX) solidphases. On the WCX solidphase at pH 4.0, catecholamines adsorption of 78% and Dopac adsorption of 68% were observed. The adsorption is (more) otherms of catecholamines on the for the WCX phase at pH 4.0 than dopamine, dopamine has greater affinity than Dopac, and this latter is coadsorbed over the adsorbed catecholamines on the WCX phase. A trial with organic solvents demonstrated that toluene selectively extracted Dopac and the coadsorbed 5-HIAA from a synthetic mix, while in a brain tissue specimen from experimental rats, Dopac and homovanilic acid (HVA) were extracted. These results served to propose an additional extraction step with organic solvents throughout the separation of acid metabolites during solidphaseextraction (EFS) for the analysis of catecholamines.
A solid-phase adsorption method was developed to circumvent the disadvantage of the conventional liquid-phase PEGylation, i.e. the heterogeneity of the PEGylated products. The model proteins, human serum albumin (HSA) and staphylokinase (SAK), were adsorbed on the ion exchange chromatography media, followed by PEGylation with succinimidyl carbonate (SC)-mPEG5K and salt elution. Since PEGylation with SC-PEG5K alters the positive charge of the proteins, Q-Sepharose Big Beads and DEAE Sepharose Fast Flow were used for adsorption of HSA and SAK, respectively. Size exclusion chromatography and SDS-PAGE studies demonstrated that solid-phase PEGylation of proteins generate monoPEGylated proteins with the yield of 35-47%. Circular dichroism and intrinsic fluorescence studies showed that solid-phase PEGylation led to little conformational change of the proteins. Solid-phase PEGylation resulted in 35% loss in the biological activity of SAK, which is lower than the liquid-phase PEGylation (70%). PMID:19343505
The ImmunoCard STAT! Cryptosporidium/Giardia rapid assay (Meridian Bioscience, Inc.) is a solid-phase qualitative immunochromatographic assay that detects and distinguishes between Giardia lamblia and Cryptosporidium parvum in aqueous extracts of human fecal specimens (fresh, frozen, unfixed, or fix...
... bioreactor by using mammalian cells instead of recombinant RNA/DNA cells. ... An Automated Glucose Control Process In Mammalian Cell Culture In Perfused ... SolidPhaseExtraction Of Polar Compounds In Water (MSC-22899-1)? ...
The active weathering front was observed to be ~ 8.3 m, as secondary clay minerals and .... Solid-phase sorbtive extraction of organic molecules in glacial ice, and 5. .... particles versus planar single crystal surfaces) affects membrane stability.
Two commercially available solidphase microextractions (SPME) fibers, polyacrylate and carboxem/polydimethylsiloxane (PDMS), were evaluated for their ability to extract hydrophilic compounds from drinking water. Conditions, such as desorption time, desorption temperature, sample...
A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new sol...
A rapid method for estimating polychlorinated biphenyl (PCB) concentrations in contaminated soils and sediments has been developed by coupling static subcritical water extraction with solid-phase microextraction (SPME). Soil, water, and internal standards are placed in a seale...
A method was developed for analysis of low levels of natural (estradiol, estrone, estriol) and synthetic (ethynylestradiol) estrogens in ground water and swine waste lagoon effluent. The method includes solidphaseextraction of the estrogens, preparation of pentafluorobenzyl der...
Abstract Ergot alkaloids (EAs) are mycotoxins which are unavoidable contaminants of cereal products, particularly rye. A method was compiled employing clean-up by cation-exchange solidphaseextraction, separation by high-pressure liquid chromatography under alkaline conditions and fluoresce...
Jun 5, 2012... from Aqueous Samples by Reversed-Phase Solid-PhaseExtraction ... Description: Extensive preparation of samples before chromatographic analysis is ... in the determination of many organic compounds in environmental ...
Urine-derived human genomic DNA (gDNA) has wide application in a variety of disciplines including clinical medicine, sports, and forensic science. We describe a novel method for gDNA extraction from urine samples using carboxylated magnetic nanoparticles (CMNPs) as solid-phaseadsorbents. Sedimentation associated with freezing of urine samples significantly reduces cell capture by CMNPs. However, the addition of 10 mM EDTA and subsequent pH modification (pH 6.0-7.1) can re-dissolve urine sediments. Purified gDNA ranged from around 0.1 kb to more than 23 kb. PCR using specific primers targeting K-ras, GAPDH, CYP3A4 and GDF5 amplified 100% of varying sized gene fragments, verifying the high quality of the isolated DNA. Successful PCR amplifications using DNA isolated from urine samples as small as 50 ?l were demonstrated. Enrichment of urine cells and subsequent adsorption of DNA can be achieved with the same CMNPs, greatly simplifying extraction procedures. The CMNP gDNA extraction technique proved to be simple, rapid, sensitive and environmentally friendly, with application for routine laboratory use and potentially within automated urine extraction platforms. PMID:22189018
A method is presented for unattended fully automated extraction and on-line determination of the atypical antipsychotic drug olanzapine in serum. An ASPEC automatic sample-preparing apparatus with Isolute cyanopropyl-bonded silicagel cartridges was used for solid-phaseextraction of the drugs from serum. The adsorbed drugs were eluted with methanol and an aliquot injected into a high-performance liquid chromatograph (HPLC) apparatus. Trifluoperazine was used as internal standard, and the analytes were separated on an unmodified silicagel column using methanol-ammonium acetate buffer pH 9.9 (85:15) as mobile phase. Ultraviolet detection at 257 nm was used for quantitation. Within the therapeutic range for the serum concentration of olanzapine, the interday variations for the quantitative determinations were <8%. Comparisons between concentrations measured using liquid-liquid extraction and the present on-line extraction method showed good agreement. Other drugs often used in combination with olanzapine did not interfere with the quantitative determinations. The method has been in routine use for more than 1 year for therapeutic drug monitoring. PMID:11206044
In this study, a method for extraction and preconcentration trace amounts of organophosphorus pesticides (OPPs) in environmental water was developed using magnetic solidphaseextraction (magnetic-SPE) followed by high performance liquid chromatography (HPLC) with UV detection. Magnetite octadecylsilane nanoparticles were synthesized and characterized by X-ray diffraction, FTIR spectroscopy, vibrating sample magnetometry and scanning electron microscopy. These nanoparticles were applied for extraction and preconcentration of OPPs (residues of diazinon and fenitrothion, which are the most-widely used for pest control in Iran) in environmental water samples at low ng mL(-1) concentration as magnetic-SPE adsorbent. The extraction conditions and efficiency of the nanoparticles for OPPs were investigated. The method was evaluated according to the reproducibility, enrichment factor, linearity range and limits of detection. Under optimized conditions, method showed good linearity between 0.03-0.06 and 30 ng mL(-1) with regression coefficients (R(2)) of 0.997 and 0.998. Limits of detection were 0.019 and 0.014 ng mL(-1). The enrichment factors of this method were 172 and 184 and the analysis yielded good reproducibility with the RSD values 7.2% and 5.4% at the 10 ng mL(-1) level (n=5) for diazinon and fenitrothion, respectively. Determination of OPPs can be easily carried out with this fast, accurate, sensitive and simple method procedure. PMID:22885050
Silicon, in the form of sodium silicate (Na2SiO3), adsorbed onto bovine serum albumin (BSA)-precoated plates served as the solid-phase antigen in an enzyme immunoassay to detect silicate-reactive antibodies in the plasma of 40 symptomatic women with silicone breast implants, 91 asymptomatic women wi...
A systematic study of the microwave-assisted extraction coupled to solid-phaseextraction of nine organophosphorus pesticides (dimethoate, diazinon, pirimiphos methyl, parathion methyl, malathion, fenthion, chlorpyriphos, methidathion and azinphos methyl) from olive oil is described. The method is based on microwave-assisted liquid-liquid extraction with partition of organophosphorus pesticides between an acetonitrile-dichloromethane mixture and oil. Cleanup of extracts was performed with ENVI-Carb solid-phaseextraction cartridge using dichloromethane as the elution solvent. The determination of pesticides in the final extracts was carried out by gas chromatography-flame photometric detection and gas chromatography-tandem mass spectrometry, using a triple quadrupole mass analyzer, for con...
Abstract in english This study aims to examine the ability of magnetic K-carrageenan beads as an adsorbent in solidphaseextraction towards chromium ions from aqueous solution. In this study, K-carrageenan magnetic gel-beads were obtained via interphase technique. The beads were kept in 0.3 M KCl to maintain gel strength. Physicochemical of the resulting materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and magnetometer. FTIR (more) results have confirmed the presence of functional groups such as sulphate esters groups. The diameter of carrageenan beads was about ~764 µm where SEM micrographs showed the spherical formed shape of carrageenan beads and a rough surface with pores. The saturation magnetization value, M, of carrageenan beads in this study was 18.78 EMU/g. The magnetic function of carrageenan beads is to facilitate bead collection and to get the Cr6+ ion that adsorbed onto the beads. The adsorption of chromium ions by magnetic carrageenan beads are through an ion exchange mechanism and formation of metal-ligand complex. Optimal timing for adsorption of chromium ions was at 60th minute. The optimal operation conditions can be achieved on pH value~1 and concentration of 100 ppm. Langmuir adsorption isotherm curve for Cr6+ is similar to Langmuir adsorption isotherm types III (unfavorable).
Scandium has been preconcentrated from a large volume of its aqueous solution after solidphaseextraction of its 1-(2-thiazolylazo)-2-naphthol chelate onto ammonium tetraphenylborate-naphthalene adsorbent in the pH range 4.0 - 5.8. The solid mass consisting of metal complex along with the adsorbent was dissolved in 5 ml of DMF and quantified by second derivative spectrophotometry. The calibration graph is linear in the concentration range 0.08 - 2.8 µg ml-1 with a correlation coefficient of 0.9998. The sensitivity of the method as found from the slope of the calibration plot is 0.185 (d2A/d?2 ) ml µg-1. Nine replicate determinations of 7.0 µg of scandium in 5 ml of final DMF solution give second derivative amplitudes as 0.255 with a relative standard deviation of 0.92%. The various instrumental and experimental variables are optimized. The conditions developed have been utilized for its determination in various standard and synthetic samples. The proposed method is found to be reproducible, reliable, sensitive, selective and economical.
There is a growing need in membrane separations for novel membrane materials providing selective retention. Molecularly imprinted polymers (MIPs) are promising candidates for membrane functionalization. In this work, a novel approach is described to prepare composite membrane adsorbers incorporating molecularly imprinted microparticles or nanoparticles into commercially available macroporous filtration membranes. The polymerization is carried out in highly viscous polymerization solvents, and the particles are formed in situ in the pores of the support membrane. MIP particle composite membranes selective for terbutylazine were prepared and characterized by scanning electron microscopy and N? porosimetry. By varying the polymerization solvent microparticles or nanoparticles with diameters ranging from several hundred nanometers to 1 µm could be embedded into the support. The permeability of the membranes was in the range of 1000 to 20,000 Lm?² ?hr?¹ ?bar?¹. The imprinted composite membranes showed high MIP/NIP (nonimprinted polymer) selectivity for the template in organic media both in equilibrium-rebinding measurements and in filtration experiments. The solidphaseextraction of a mixture of the template, its analogs, and a nonrelated compound demonstrated MIP/NIP selectivity and substance selectivity of the new molecularly imprinted membrane. The synthesis technique offers a potential for the cost-effective production of selective membrane adsorbers with high capacity and high throughput. PMID:22641529
We report here the synthesis of a new sorbent comprising silica-coated magnetic nanoparticles (SCMNPs) modified with {gamma}-mercaptopropyltrimethoxysilane ({gamma}-MPTMS) for solidphaseextraction of trace amounts of Cd, Cu, Hg, and Pb from biological and environmental samples. The prepared nanoparticles were characterized by infrared spectroscopy, transmission electron microscopy, and static adsorption-desorption experiments. These magnetic nanoparticles carrying the target metals could be easily separated from the aqueous solution simply by applying an external magnetic field; no filtration or centrifugation was necessary. Using this novel magnetic material, we have developed an efficient and cost-effective two-step method for detecting trace amounts of Cd, Cu, Hg, and Pb in environmental and biological samples. The first step of the method is a separation/preconcentration step, in which metals are adsorbed onto {gamma}-MPTMS-SCMNPs. In the second step, inductively coupled plasma mass spectrometry is used to study the adsorbed metals. The effects of pH, sample volume, eluent, and interfering ions have been investigated. Under the optimized conditions, the limits of detection for Cd, Cu, Hg, and Pb were as low as 24, 92, 107, and 56 pg L{sup -1}, respectively. Relative standard deviations (RSDs, C = 2 ng L{sup -1}, n = 7) were 6.7%, 9.6%, 8.3%, and 3.7%, respectively.The proposed method has been validated using three certified reference materials, and it has been applied successfully in the determination of trace metals in biological and environmental samples.
A solid-phaseextraction method for the preconcentration of Fe, Mn and Zn on a column containing Ambersorb 572 has been developed, and the determination of Fe, Mn and Zn in water using a flame atomic absorption spectrophotometer (FAAS) has been performed. The optimum preconcentration parameters of the procedure have been determined. The effect of the pH, complexing agent, amount of adsorbent, flow rate, concentration and volume of the elution solution and interfering ions on the recovery of the analytes were investigated. The recoveries of Fe, Mn and Zn were 99 ± 3%, 98 ± 3% and 99 ± 3% at the 95% confidence level, respectively, under the optimum conditions. Fe, Mn and Zn were preconcentrated up to 50, 100, 200, respectively. The limits of detection of Fe, Mn and Zn are 2.5, 0.68 and 0.24 ?g l-1, respectively. The adsorption capacity of the adsorbent was found to be 10.9, 13.1 and 21.5 mg g-1 for Fe, Mn and Zn, respectively. The method has been applied to the determination of these metal ions in tap-water and river-water samples. The precision and the accuracy of the method is very good. The relative standard deviation and the relative error are lower than 4%.
In this study, an automated sequential injection lab-on-valve (SI-LOV) system was designed for the on-line matrix removal and preconcentration of quercetin. Octadecyl functionalized magnetic silica nanoparticles were prepared and packed into the microcolumn of the LOV as adsorbents. After being adsorbed through hydrophobic interaction, the analyte was eluted and subsequently introduced into the electrochemical flow cell by voltammetric quantification. The main parameters affecting the performance of solid-phaseextraction, such as sample pH and flow rate, eluent solution and volume, accumulation potential and accumulation time were investigated in detail. Under the optimum experimental conditions, a linear calibration curve was obtained in the range of 1.0 × 10(-8) to 1 × 10(-5) mol L(-1) with R(2) = 0.9979. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.3 × 10(-9) and 4.3 × 10(-9) mol L(-1), respectively. The relative standard deviation (RSD) for the determination of 1.0 × 10(-6) mol L(-1) quercetin was found to be 2.9% (n = 11) along with a sampling frequency of 40 h(-1). The applicability and reliability of the automated method described here had been applied to the determination of quercetin in human urine and red wine samples through recovery experiments, and the obtained results were in good agreement with those obtained by the HPLC method. PMID:22489286
A novel Schiff base-chitosan-grafted multiwalled carbon nanotubes (S-CS-MWCNTs) solid-phaseextractionadsorbent was synthesized by covalently grafting a Schiff base-chitosan (S-CS) onto the surfaces of oxidized MWCNTs. The adsorbent was characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and thermal gravimetric analysis. The results showed that S-CS was successfully grafted onto the surfaces of MWCNTs. A method was developed for the determination of heavy metals, namely V(V), Cr(VI), Cu(II), As(V) and Pb(II) in biological and environmental samples by inductively coupled plasma mass spectrometry coupled with preconcentration with S-CS-MWCNTs. The parameters influencing preconcentration of target ions, such as the pH of the sample solution, the flow rate of sample loading, the eluent concentration, and eluent volume, were investigated and optimized. Under the optimal conditions, the enrichment factors of V(V), Cr(VI), Cu(II), As(V), and Pb(II) reached 111, 95, 60, 52, and 128, respectively, and the detection limits were as low as 1.3-3.8 ng L(-1). The developed method was successfully applied to the determination of trace-metal ions in herring, spinach, river water, and tap water with good recoveries ranging from 91.0% to 105.0%. PMID:22497719
A separation and preconcentration method based on solid-phaseextraction using sulfoxide adsorbent was developed for the determination of Hg(II) in natural water samples by inductively coupled plasma mass spectrometry (ICP-MS). The sulfoxide adsorbent was packed into a commercially available syringe-driven column (with a bed volume of 1.0 mL), which permitted off-line sample loading and on-line elution/measurement. The optimized operating conditions were as follows: sample condition for Hg(II) adsorption, 0.5% HCl; sample-loading flow rate, 10 mL min?1; eluent for recovering Hg(II), 1% cysteine water solution. A test using multi-element mixed solution showed that most trace elements in natural water, except for Bi, could be completely separated from Hg(II). The recoveries of Hg(II) were 99.0 ± 3.2 and 100.7 ± 4.3%, respectively, when 0.64 and 0.16 ng mL?1 of Hg(II) were added into the test sample. The detection limit of Hg(II) using a quadrupole ICP-MS after 10-fold preconcentration was 1.5 pg mL?1. The blank value was 2.8 ± 0.5 pg mL?1.
A molecularly imprinted polymer (MIP) was prepared using chlorsulfuron (CS), a herbicide as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a cross-linker, methanol and toluene as a porogen, and 2,2-azobisisobutyronitrile as an initiator. The binding behaviors of the template chlorsulfuron and its analog on MIP were evaluated by equilibrium adsorption experiments, which showed that the MIP particles had specific affinity for the template CS. Solid-phaseextraction (SPE) with the chlorsulfuron molecularly imprinted polymer as an adsorbent was investigated. The optimum loading, washing, and eluting conditions for chlorsulfuron molecularly imprinted polymer solid-phaseextraction (CS-MISPE) were established. The optimized CS-MISPE procedure was developed to enrich and clean up the chlorsulfuron residue in water, soils, and wheat plants. Concentrations of chlorsulfuron in the samples were analyzed by HPLC-UVD. The average recoveries of CS spiked standard at 0.05~0.2 mg L(-1) in water were 90.2~93.3%, with the relative standard deviation (RSD) being 2.0~3.9% (n=3). The average recoveries of 1.0 mL CS spiked standard at 0.1~0.5 mg L(-1) in 10 g soil were 91.1~94.7%, with the RSD being 3.1~5.6% (n=3). The average recoveries of 1.0 mL CS spiked standard at 0.1~0.5 mg L(-1) in 5 g wheat plant were 82.3~94.3%, with the RSD being 2.9~6.8% (n=3). Overall, our study provides a sensitive and cost-effective method for accurate determination of CS residues in water, soils, and plants. PMID:21805075
In this study, an extraction and preconcentration technique using solid-phaseextraction (SPE) along with hollow fiber (HF) has been developed as an ultra-preconcentration technique for some triazole pesticides in aqueous samples. Triazole pesticides were employed as model compounds to assess the method and were monitored by gas chromatography-flame ionization detection (GC-FID). Initially, an aqueous solution of target analytes was passed through an RP-8 SPE cartridge and then the adsorbed analytes were eluted with ?L amounts of toluene. The collected elute was slowly introduced into an HF that had one end blocked. This allowed precipitation inside the lumen and pores of the HF. Finally, the obtained HF was mounted on a home-made solid-phase microextraction syringe and entered into the GC injection port for thermal desorption-GC analysis. The effect of various experimental parameters including injection port temperature, desorption time, state of HF, washing solvent, elution solvent and its volume, sample volume, etc. were investigated for finding the optimum conditions. The calibration graphs were linear in the ranges of 2-1000 ng/mL (penconazole and hexaconazole), 5-1000 ng/mL (tebuconazole), 15-1000 ng/mL (triticonazole) and the detection limits (LODs) ranged from 0.6 to 4.5 ng/mL. The enhancement factors were in the range of 870-950. The relative standard deviations (RSD%) for five repeated experiments (C=250 ng/mL of each pesticide) varied from 4.5 to 8.7%. The relative recoveries obtained for analytes in grape juice samples, spiked with different levels of each pesticide, were in the range of 87-119%. PMID:22102618
The present study investigates the application of carbon coated Fe(3)O(4) (Fe(3)O(4)/C) magnetic nanoparticles as an adsorbent for magnetic solidphaseextraction (MSPE) of trace amounts of organophosphorus pesticides (OPPs) from environmental water samples and their determination using high performance liquid chromatography with ultraviolet detection (HPLC-UV). The Fe(3)O(4)/C magnetic nanoparticles were synthesized by a simple hydrothermal reaction and the resultant material was characterized by X-ray powder diffraction, field emission scanning electron microscopy and Fourier transform infrared. Central composite design combined with desirability function (DF) was applied to find the experimental conditions providing the highest global extraction efficiency. These conditions were found in correspondence with a solution pH of 9.16, 97.4 mg Fe(3)O(4)/C and 10 mmol L(-1) NaCl added to samples. Under the optimal conditions, the proposed method was evaluated, and applied to the analysis of OPPs in water samples. The results demonstrated that our proposed method had wide dynamic linear range (0.05-400 ng mL(-1)) with a good linearity (R(2)>0.9949) and low detection limits (4.3-47.4 pg mL(-1)). High enrichment factors were achieved ranging from 330-1200. The established MSPE-HPLC-UV method has been successfully applied for the determination of the OPPs in spiked water samples (well, tap, river and mineral). Satisfactory recovery results showed that the matrices under consideration do not significantly affect the extraction process. PMID:22967515
In this paper, 1-hexadecyl-3-methylimidazolium bromide (C(16)mimBr)-coated Fe(3)O(4) magnetic nanoparticles (NPs) as an adsorbent of mixed hemimicelles solid-phaseextraction was investigated for the preconcentration of two chlorophenols (CPs) in environmental water samples prior to HPLC with UV detection at 285 nm. The high surface area and excellent adsorption capacity of the Fe(3)O(4) NPs after modification with C(16)mimBr were utilized adequately in the SPE process. By the rapid isolation of Fe(3)O(4) NPs through placing a strong magnet on the bottom of beaker, the time-consuming preconcentration process of loading large volume sample in conventional SPE method with a column can be avoided. A comprehensive study of the adsorption conditions such as the zeta-potential of Fe(3)O(4) NPs, added amounts of C(16)mimBr, pH value, standing time and maximal extraction volume were also presented. Under optimized conditions, two analytes of 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) were quantitatively determined. The method was then used to determine the two CPs in real environmental water samples. The accuracy of method was evaluated by recovery measurements on spiked samples. Good recovery results (74-90%) were achieved. It is important to note that satisfactory preconcentration factors and extraction recoveries for the two CPs were obtained with only a small amount of Fe(3)O(4) NPs (40 mg) and C(16)mimBr (24 mg). PMID:22244175
The quantitative extraction of bile acids and their conjugates from serum was investigated using different commercially available reversed-phase bonded silica cartridges. Serum was diluted with 0.1 M sodium hydroxide or 0.5 M triethylamine sulphate, pH 7.0, and heated at 64 degrees C for 20-30 min prior to application to the cartridge. Bile acids were adsorbed to the bonded silica particles, and recovered by elution with a small volume of methanol. Dilution of serum with triethylamine sulphate gave quantitative extraction of bile acids from serum using Bond-Elut C18 cartridges, but the milder conditions of the applied sample compared with dilution with sodium hydroxide permitted re-use of the cartridges with no loss in performance, and gave relatively clean extracts. Large variations in the recovery of bile acids were observed using sorbents from different manufacturers. These studies highlight the need to evaluate critically the performance characteristics of solid-phase cartridges when the manufacturer or batch lot is changed. PMID:8821862
The effect of dissolved humic acids on the recovery of PAHs from water samples has been investigated using a commercially available humic acid preparation as colloid model and a mixture containing the 16 EPA PAHs. The presence of humic acid reduced the extraction efficiency down to between 10 and 75%. An analytical protocol was therefore developed for the accurate determination of PAHs in the presence of humic acids based on isotope dilution mass spectrometry. The procedure compensates for losses due to sorption of PAHs and can be used for the determination of the total PAH concentration in water, i.e. dissolved PAHs plus PAHs adsorbed on colloids. To obtain reliable estimates it is essential to allow a certain time for equilibration between the isotope spike and the aqueous matrix which may vary between 5 and 24 h, in correlation with the water solubility of PAHs. The protocol allows one to recover the 16 PAHs studied at 94 to 105%. The expanded uncertainty of the measurements was 5-7% for all PAHs. Liquid-liquid extraction and solid-phaseextraction in combination with the developed isotope dilution protocol performed equally well for the quantification of PAHs from water samples rich in colloidal material. (orig.)
In the present study, an effective method is presented for the separation and preconcentration of uranium (VI) by solidphaseextraction (SPE). For this purpose, U(VI) oxinate is formed by the reaction of U(VI) with 8-hydroxyquinoline and adsorbed onto the octylsilane (C-8) SPE cartridge. The analyte is completely eluted with chloroform and determined by differential pulse polarography. The SPE conditions were optimized by evaluating the effective factors such as pH, oxine concentration, type and concentration of buffer and masking agent. By the proposed method a preconcentration factor more than 100 was achieved. The average recovery of uranium (VI) oxinate (0.1 mg l(-1)) was 99.8%. The relative standard deviation was 1.6% for seven replicate determinations of uranyl ion in the solution with a concentration 20 mug l(-1). Some concomitant ions such as Ca(+2), Mg(+2) and Fe(+3) which interfere in extraction or determination process of uranium were masked with EDTA in aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in Caspian Sea and Persian Gulf water samples. PMID:18967134
A solid-phaseextraction procedure for estradiol-17? from bovine blood plasma with a reversed phase cartridge was developed for the measurement of its concentration by radioimmunoassay. Estradiol-17? retained in the cartridge was eluted quantitatively with 70%(v/v) methanol, although estrone was recovered in the same fraction. The apparent values measured by dextran-coated charcoal radioimmunoassay with an eluent of 75%(v/v) methanol in the solid-phaseextraction declined approximately by 10% as applied plasma volume was increased by 1 ml (r=-0.98, p<0.001). However, the values by double antibody radioimmunoassay were elevated approximately 8% per 1 ml plasma increase (r=0.82, p<0.001). The recovery of estradiol-17? added to bovine plasma in the extraction and radioimmunoassay with dextran-coated charcoal separation was approximately 75% under conditions of 2 ml plasma application, and concentrations calculated using buffer standards. Matrix effects on the assay recovery were negligible in the addition of solid-phaseextract of castrated bull plasma to the standards. On the other hand, the average recoveries calculated with buffer and process standards in double antibody radioimmunoassay were 170% and 110%, respectively. The assay value in the solid-phaseextraction showed good agreement with the value in the liquid-liquid extraction and liquid chromatography after correction with the recovery rate (r=0.99). In conclusion, solid-phaseextraction with a reversed phase cartridge is a practical extraction method for the measurement of estradiol-17? during the estrous cycle in cattle.
In this work, the caffeine and some catechin compounds (+) C, EC, and EGCG were extracted from green tea by using two molecular imprinted polymers (MIPs) as sorbent materials in a multi-solid-phaseextraction (SPE) process known as MISPE (molecular imprinted solid-phaseextraction). To obtain synthesis of MIP, (+) catechin (and caffeine) was employed as the template, AM (and MAA) as the monomer, EGDMA as the crosslinker, and AIBN as the initiator. A solution of (+) catechin (and caffeine) (0.2 mg/mL in methanol) was utilized in the solid extraction cartridges following loading, washing, and elution procedures with acetonitrile, methanol, and methanol/acetic acid (90/10, %v/v) as the solvents, respectively. This multi-solid-phaseextraction protocol was applied for the extraction of ca...
Supercritical fluid extraction (SFE) with carbon dioxide has become an increasingly popular alternative method to Soxhlet extraction for the measurement of organic compounds adsorbed on solid matrices. he application of SFE to air sampling materials for recovery of adsorbed (coll...
A method of activating a carbon adsorbent is described, which comprises oxidizing the surface of the carbon adsorbent with a mild oxidizing acid in the presence of a metal oxidation catalyst at an elevated temperature and boiling the mixture of the carbon adsorbent, mild oxidizing acid and metal oxidation catalyst to dryness. Then rinse the surface oxidizing carbon adsorbent with water; and dry the rinsed surface oxidized carbon adsorbent. In a process for the removal of water or carbon dioxide from a gas stream containing water or carbon dioxide of the type wherein the gas stream containing water or carbon dioxide is contacted with a solidphaseadsorbent under pressure-swing adsorption or thermal-swing adsorption processing conditions, the improvement is described comprising utilizing an adsorbent produced by the activation of a carbon adsorbent. The activation comprises oxidizing the surface of the carbon adsorbent with a mold oxidizing acid in the presence of a metal oxidation catalyst at an elevated temperature and boiling the mixture of the carbon adsorbent, mild oxidizing acid and metal oxidation catalyst to dryness. Then rinse the surface oxidized carbon adsorbent with water; and dry the rinsed surface oxidized carbon adsorbent.
Advection of ammonia gas into unsaturated sediments was investigated to evaluate changes in uranium phase mobility, changes in sediment mineralogy, changes in sediment physicochemical properties, and influence on the mobility of other metals. Sediments used in this study were field contaminated with different mixtures of U surface phases including aqueous/adsorbed U, carbonate-associated U, and Na-boltwoodite (hydrous U silicate). The overall change in uranium in pore water, adsorbed on the surface, and in other surface phases after each treatment was evaluated over time with a series of six liquid extractions to dissolve specific surface phases and X-ray fluorescence identification of U mineral phases. Advection of ammonia gas into 1-D and 2-D sediment systems shows advection and pore water partitioning is dependent on the air permeability and water content. Ammonia gas advection into sediment rapidly partitions into pore water, increasing the pH, which was dependent on the ammonia gas concentration. The subsequent dissolution of some aluminosilicates causes temporary increased mobility of some metals (Tc, Sr), although low water content advection in the vadose zone is slow, so mobilization is localized. Over time (months), natural sediment buffering decreases the pH to natural conditions and precipitates form that decrease the uranium mobility compared to the initial conditions. Subsequent advection of nitrogen gas or air results in a more rapid pH decrease to natural conditions. Long-term changes in U surface phases include decreased aqueous, adsorbed, and carbonate-associated U, and increased U associated with silicates. Ammonia gas treatment of sediments that contained predominantly Na-boltwoodite did appear to dissolve this U phase, but solidphase analysis of long-term samples indicated predominantly Na-boltwoodite was present, indicating it may have reprecipitated. It is hypothesized that aluminosilicate precipitation under alkaline conditions are coating U surface phases. Because the advection of ammonia gas into U-contaminated sediments results in decreased U mobility and the processes can be generally predicted, field-scale tests are planned.
A solid-phase radioimmunoanalysis of plasma membrane molecules solubilized in the presence of detergent was developed. From a crude cell lysate, membrane molecules were specifically immobilized by solid-phaseadsorbed monoclonal antibodies. Analysis of these molecules was easily performed with radiolabeled monoclonal antibodies of different specificities. This technique was used to analyze the HLA-DR and HLA-A,B,C molecules by RAJI cells. It was possible (a) to determine which epitopes are expressed on the same molecules; (b) to define subsets of HLA molecules according to the epitopes which they express, and (c) to perform quantitative analysis of HLA molecules on a crude cell lysate.
Quartz crystal microbalance techniques and in situ spectroscopic ellipsometry are used to probe the structure-dependent intrinsic viscoelastic properties of self-assembled CH{sub 3}(CH{sub 2}){sub 8}SH alkanethiol monolayer adsorbed from the gas phase onto Au(111)-textured substrates. Physisorbed molecules, mixed chemisorbed-fluid/solidphases and solid-phase domain boundaries make sequentially dominant contributions to the measured energy dissipation in the growing monolayer. Deviations from Langmuir adsorption kinetics reveal a precursor-mediated adsorption channel. These studies reveal the impact of structural heterogeneity in tribological studies of monolayer lubricants.
A solid-phase reagent based on 1-(4-adamantyl-2-thiasolylazo)-2-naphthol adsorbed onto silica gel was prepared for Co(II) recovery and preconcentration prior to its sorption-spectroscopic detection. The immobilized reagent was applied to the determination of free cobalt ions in natural water. The solid-phase reagent and chemiluminescent method coupled with membrane filtration, gel-permeation and ion-exchange chromatography were applied to the study of the speciation of iron and cobalt in water from the Dnieper reservoirs and lakes of Kyiv City; their predominant forms were complexes of Fe(III) and Co(II) with dissolved organic matter and fulvic acids play a main role in their complexation. (orig.)
A solid-phase reagent based on 1-(4-adamantyl-2-thiasolylazo)-2-naphthol adsorbed onto silica gel was prepared for Co(II) recovery and preconcentration prior to its sorption-spectroscopic detection. The immobilized reagent was applied to the determination of free cobalt ions in natural water. The solid-phase reagent and chemiluminescent method coupled with membrane filtration, gel-permeation and ion-exchange chromatography were applied to the study of the speciation of iron and cobalt in water from the Dnieper reservoirs and lakes of Kyiv City; their predominant forms were complexes of Fe(III) and Co(II) with dissolved organic matter and fulvic acids play a main role in their complexation. PMID:12733020
Abstract Florisil solid-phaseextraction (SPE) cartridges were used for purifying ciguatoxin-contaminated (CTX-contaminated) coral fish extracts, with an aim to removing extracted lipid but retaining optimal level of CTXs in the purified fractions. CTX-containing fraction (target fraction) i...
8 pages, 6 tables, 4 figures. | A new analytical method based on the use of pressurized liquid extraction (PLE) followed by solid-phaseextraction with LiChrolut RP C18 cartridges was evaluated for the sample preparation, extraction, and cleanup of eight naturally occurring benzoxazinone derivatives...
Formica polyctena antidiuretic factor (FopADF) was purified from a 15% trifluoroacetic acid (TFA) extract of the abdomens of 150,000 worker ants. After solidphaseextraction of the crude extract and reversed-phase HPLC on two C-18 columns, an antidiuretic factor was isolated. Tested at a concentrat...
Chemical-warfare agents (CWAs) are toxic chemicals intended for use in mass destruction and terrorist attacks. Their presence in the environment is of great concern due to their rapid distribution and toxicity. The Organization for the Prohibition of Chemical Weapons conducts proficiency tests for the offsite analysis of samples contaminated with CWAs and their degradation or oxidation products. In this article, we review recent trends in the development of sample-preparation techniques for efficient extraction of Chemical Weapons Convention-related chemicals from environmental and industrial samples. We discuss extraction methodologies (e.g., solvent extraction, solid-phase microextraction, solid-phaseextraction, and gas-phase and headspace analysis) and their advances.
A simple, rapid and economized method was developed for PAH determination in soil and oil samples. The PAHs in the crude extracts first were separated from contaminations by solid-phaseextraction and then determined by HPLC with UV- or fluorescence detection. HPLC in combination with fluorescence detection is a selective and sensitive method. For each compound the detection limit is in the range of 3 to 30 pg. The advantages of this method using solid-phaseextraction and HPLC separation technique in comparison to liquid/liquid extraction or GC results in economical working. (orig.).
In this article, a new method for the determination of triazine herbicides atrazine and simazine in environment aqueous samples was developed. It was based on solid-phaseextraction (SPE) using bamboo charcoal as adsorbent and high-performance liquid chromatography-ultraviolet detector (HPLC-UV) for the enrichment and determination of atrazine and simazine at trace level. Related important factors influencing the extraction efficiency, such as the kind of eluent and its volume, flow rate of the sample, pH of the sample, and volume of the sample, were investigated and optimized in detail. Under the optimal conditions, the experimental results showed that excellent linearity was obtained over the range of 0.5-30 microg L(-1) with correlation coefficients 0.9991 and 0.9982, for atrazine and simazine, respectively; and the relative standard deviations of two analytes were 8.3, 8.7%, respectively. The proposed method was successfully applied to the analysis of tap water and well water samples. And satisfactory spiked recoveries were obtained in the range of 75.2-107.1%. The above results indicated that the developed method was an excellent alternative for the routine analysis in environmental field. PMID:18656684
In this paper, a simple and cheap method for the simultaneous preconcentration and sensitive determination of three hexabromocyclododecane (HBCD) diastereomers (?-, ?-, and ?-HBCD) in environmental water samples has been developed. It was based on solidphaseextraction (SPE) and rapid resolution liquid chromatography-electrospray tandem mass spectrometry. Bamboo charcoal, one kind of cheap material, was investigated and used as SPE adsorbent for the enrichment and determination of HBCD diastereomers. Related important parameters affecting extraction efficiencies, including type and volume of eluant, amount of sorbent, sample pH, flow rate, and sample volume, were investigated and optimized in detail. Under the optimum conditions, experimental data exhibited excellent linear relationships between peak area and concentrations over the range 0.1-10 ?g L(-1). The limits of detection and precision were in the range of 0.005-0.015 ?g L(-1) and 4.59-7.47%, respectively. The proposed method has been successfully applied for the trace analysis of HBCD diastereomers in real-world environmental water samples. PMID:21409609
In this work, magnetic carbon nanotubes (CNTs) were prepared by mixing the magnetic particles and multi-walled carbon nanotubes dispersed solutions. Due to their excellent adsorption capability towards hydrophobic compounds, the magnetic CNTs were used as adsorbent of magnetic solid-phaseextraction (MSPE) to extract phthalate acid esters (PAEs), which are widely used in many consumable products with potential carcinogenic properties. By coupling MSPE with gas chromatography/mass spectrometry (GC/MS), a rapid, sensitive and cost-effective method for the analysis of PAEs was established. Our results showed that the limits of detection (LODs) of 16 PAEs ranged from 4.9 to 38 ng L(-1), which are much lower compared to the previously reported methods. And good linearities of the detection method were obtained with correlation coefficients (R(2)) between 0.9821 and 0.9993. In addition, a satisfying reproducibility was achieved by evaluating the intra- and inter-day precisions with relative standard deviations (RSDs) less than 11.7% and 14.6%, respectively. Finally, the established MSPE-GC/MS method was successfully applied to the determination of PAEs from bottled beverages, tap water and perfume samples. The recoveries of the 16 PAEs from the real samples ranged from 64.6% to 125.6% with the RSDs less than 16.5%. Taken together, the MSPE-GC/MS method developed in current study provides a new option for the detection of PAEs from real samples with complex matrices. PMID:22340126
Solid-phaseextraction has become one of the most commonly used techniques for preconcentration of analytes from environmental samples. In the standard use of solid sorbent phases the extracted pollutants are subsequently eluted with a suitable organic solvent before chromatographic analysis. An alternative to this procedure is analysis of the adsorbed and concentrated pollutants by direct application of a spectroscopic method (fluorimetry or absorptiometry) to the phase. Although this method cannot be expected to give results as precise as those given by chromatographic methods, it might have valuable applications, particularly for ''on site'' pollution monitoring. This paper reports an evaluation of the capability of the method for the spectrophotometric detection of BTX (benzene, toluene, xylenes) in aqueous media and in contaminated atmospheres, with polydimethylsiloxane (PDMS) as sorbent. The tests performed, with the estimated detection limits, indicate that the method is relatively simple and easy to operate and sensitive enough for application to the monitoring of pollution both in water and in air in an industrial ambient atmosphere. (orig.)
In this work the purpose was to develop accurate and reproducible methods for the qualitative and quantitative analysis of pesticides/herbicides, phthalates, chlorinated solvents, trihalomethanes, polycyclic aromatic hydrocarbons (PAHs) and chlorophenols in drinking waters, using solid-phase micro extraction and GC-MS techniques. The SPME developed by J. Pawliszyn and co-workers, consists of an fused silica fibre, coated with an appropriate absorbent phase, hosted inside the needle of a holder that looks like a GC-syringe; the needle pierces the septum of a sealed vial and the fibre is lowered, by depressing the plunger of the holder, into the liquid (or in the headspace, if that is the case) that contains the analytes of interest. After a set period of time, necessary to reach the partitioning equilibrium, the fibre is retracted inside the needle, the needle is inserted into the GC injector port and the fibre pushed in the heated injector. Here the compounds of interest (that have adsorbed onto the fibre) are thermally desorbed and analysed by GC-MS. After three minutes the fibre is extracted and is ready for a new analysis. The SPME technique has already found many applications in food and environmental analysis. Many of the analytes investigated in this research are listed Italian legislation as possible pollutants of drinking waters and their presence and concentrations require monitoring. The list of compounds included in this work is reported in Table 1.
Kinetics of water spreading on the surface of solidphases of various carbon materials has been first studied with the use of high-speed video filming (up to 1200 frames per second). It has been found that rates of low-temperature liquid and metal melts spreading and wetting the surface of solidphases are close in time (the process length is 10?2?10?3s) and in both the cases the spreading occurs in an inert mode. It has been shown that at the final stages the spreading of low-temperature liquids occurs at a viscous mode (10?30 min) caused by the presence of an adsorbed layer (coat) on the solidphase surface due to the environment.
Abstract in portuguese Foram preparadas resinas quitosana de ligação cruzada com impressão molecular de uranil e sem impressão, possuindo grupamentos quinolin-8-ol. Em todos os casos um efeito de impressão significativo foi observado na comparação do percentual de extração de urânio (VI). A resina com impressão molecular foi usada para pré-concentração extrativa de urânio (VI) em fase sólida antes de determinação espectrofotométrica. Variáveis experimentais que influenciam a (more) extração quantitativa de urânio (VI) foram otimizadas em método estático e em extração com coluna. A capacidade de retenção de urânio (VI) foi de 218 mg por g de resina, que é maior que a resina sem impressão molecular correspondente ou outra fase sólida adsorvente que possua grupamento quinolin-8-ol. O intervalo de pH ótimo encontrado foi 4,5-7,0. O urânio adsorvido foi fácil e quantitativamente eluido com HCl 1 mol L-1 (10 mL) sob uma vazão de 2 mL min-1. Estudos de interferentes mostraram uma alta tolerância para diversos íons e espécies eletrolíticas. O limite de detecção foi de 2 µL L-1 e o intervalo de concentração linear de 5-100 µg L-1. A exatidão do método foi testada com material padrão de referência de rocha de urânio. Além disso, o método foi aplicado para a determinação de urânio em amostras de solo contaminado e sedimento. Abstract in english The uranyl-ion-imprinted and non-imprinted cross-linked chitosan resins possessing quinoline-8-ol moiety have been prepared. In all the cases, a significant imprinting effect was noticed on comparing percent extraction of uranium (VI). The resulting ion-imprinted resin was used for solidphaseextractive preconcentration of uranium (VI) prior to its determination by spectrophotometry. Experimental variables that influence the quantitative extraction of uranium (VI) were o (more) ptimized by both static and column methods. The retention capacity found for uranium (VI) was 218 mg g-1 of resin which is higher than the corresponding non-imprinted resins and other solidphaseextraction sorbents possessing quinoline-8-ol moiety. The optimum pH range was 4.5-7.0. Uranium adsorbed was easily and quantitatively eluted with 1 mol L-1 HCl (10 mL) at a flow rate of 2 mL min-1. Interference studies showed a high tolerance of diverse ions and electrolyte species. The limit of detection was 2 µg L-1 and the dynamic linear range was 5-100 µg L-1. The accuracy of the developed method was tested with one uranium ore standard reference material. Furthermore, the proposed method was successfully applied for the determination of uranium in contaminated soil and sediment samples.
This paper describes a new method for the determination of citalopram in biological fluids using molecularly imprinted solid-phaseextraction as the sample cleanup technique combined with high performance liquid chromatography. The molecularly imprinted polymers were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker, chloroform as porogen and citalopram hydrobromide as the template molecule. The novel imprinted polymer was used as a solid-phaseextraction sorbent for the extraction of citalopram from human serum and urine. Effective parameters on citalopram retention were studied. The optimal conditions for molecularly imprinted solid-phaseextraction consisted of conditioning with 1?mL methanol and 1?mL of deionized water at neutral pH, l...
A rapid and reliable solid-phaseextraction method for HPLC analysis of opium alkaloids from Papaver plants was established. Fifty mg of dried and powdered plant sample was extracted with 5 ml of 5% acetic acid for 30 min under sonication. After centrifugation, 3 ml of the supernatant was loaded on a reversed-phase cation-exchange solid-phaseextraction cartridge. After seriate washings with 0.1 M hydrochloric acid and methanol, alkaloids were eluted with a mixture of 28% ammonia and methanol (1 : 19). The eluate was concentrated under nitrogen stream at 40 °C and the residue was dissolved in 50% aqueous methanol for high performance liquid chromatographic analysis. With this solid-phaseextraction method, the recovery of morphine, codeine, oripavine, thebaine, papaverine, noscapine and sanguinarine was from 99.94 to 112.18% when the standard alkaloids were added to the plant samples. Opium alkaloids of a variety of genus Papaver plants cultivated in a field and phytotron were analyzed by this method.
Endemic of avian influenza virus (AIV) in Asia and epizootics in some European regions have caused considerable public concern on a possible pandemic of AIV. A rapid method for virus detection and effective surveillance in wild avian, poultry production as well as in humans is required. In this article, a DNA microarray-based solid-phase polymerase chain reaction (PCR) approach has been developed for rapid detection of influenza virus type A and for simultaneous identification of pathogenic virus subtypes H5 and H7. This solid-phase RT-PCR method combined reverse-transcription amplification of RNA extract in the liquid phase with sequence-specific nested PCR on the solidphase. A simple ultraviolet cross-linking method was used to immobilize the DNA probes over an unmodified glass surface, which makes solid-phase PCR a convenient possibility for AIV screening. The testing of 33 avian fecal and tracheal swab specimens was completed in less than 2 h with 94% accuracy.
This study developed an acid hydrolysis coupled to a solid-phase microextraction method employing a semi-microcolumn liquid chromatography system, instead of enzyme hydrolysis with solid-phaseextraction for the pretreatment of human urine samples, to detect urinary 1-hydroxypyrene (1-OHP). The complete separation and detection of urinary 1-hydroxyprene was performed using a high-performance liquid-chromatography fluorescence detection system with an analytical C18 semi-microcolumn, 60% (v/v) aqueous acetonitrile elution, and a ?ex/em = 348/388 nm pair detection wavelength. Calibration graphs were linear with very good correlation coefficients (r = 0.9997), and the detection limit was 1.0 ng/L. These important parameters for acid hydrolysis and solid-phase microextraction were investigated. The total recovery was above 83% in acid hydrolysis with solid-phase microextraction. The proposed method provided a relatively simple, convenient, and practical procedure to determine the level of urinary 1-hydroxypyrene in biological samples, and was successfully applied to detect the urine of students.
The present study reports an improved method to quickly and reproducibly isolate the saccharides from a variety of dairy and soy products utilizing reversed-phase solid-phaseextraction to quantitatively remove fats, fatty acids, and lipids followed by desalination and deproteinization by ion-exchange solid-phaseextraction with no loss of saccharides during extraction. Analysis of the isolated saccharides was performed by ligand-exchange HPLC. The method presented requires no prolonged heating (thus protecting the saccharides from hydrolysis or isomerization), uses benign reagents, and realizes a significant time savings over existing methods. The isolation and analysis of monosaccharides (glucose, galactose and fructose), disaccharides (lactose and sucrose), and polysaccharides (raffinos...
A methodology based on chemometrics and quantum chemistry was proposed to design and synthesize dummy molecularly imprinted polymers (DMIPs) capable of extracting chloroacetamide herbicides from food samples. Molecular modeling approach in conjunction with clustering analysis was used to predict the most suitable dummy template. Metolachlor deschloro was selected as the template to synthesize DMIPs, which were used as the solidphaseextraction (SPE) materials. The selective adsorption of DMIPs was evaluated by high performance liquid chromatography (HPLC). The retention property of six chloroacetamide herbicides on DMIPs was also predicted using clustering analysis. The optimum loading, washing and eluting conditions for dummy molecularly imprinted solidphaseextraction (DMISPE) were est...
The state and solubility of cadmium in waste-treated soils was investigated. Three sets of experiments were designed to elucidate solidphase control of soil solution cadmium. First, the soil solution composition of two soils amended with either sludge or metal contaminated mulch was examined to determine the presence of anions capable of precipitating or co-precipitating cadmium. Results indicated that no known pure solidphases of cadmium developed but that high concentrations of phosphate, sulfate and carbonate apparently influenced cadmium solubility. Secondly, three soils were amended with 10 ug of cadmium as cadmium acetate/g of soil. Three different levels of glycerophosphate, cysteine and acetate were added to the soils and incubated at constant temperature and water content in order to release phosphate, sulfate and alkalinity under conditions conducive for homogeneous precipitation. Another set of treatments was prepared in the same fashion with an additional amendment of calcium carbonate to raise soil pH's to 7.0. In the presence of sulfate, cadmium solubility increased with no apparent solidphase formation. The addition of calcium carbonate shifted solidphase control to either calcium carbonate or calcium sulfate. The generation of alkalinity by acetate addition produced solidphase calcium carbonate which in turn controlled cadmium solubility through chemisorption of cadmium on calcite surfaces. In the presence of monobasic calcium phosphate, cadmium was interfacially adsorbed. In the presence of dibasic calcium phosphate, however, cadmium was homogeneously precipitated in the host crystal suggesting possible solid solution.
A simple and fast sample pre-treatment method based on matrix solid-phase dispersion (MSPD) for isolating cocaine, benzoylecgonine (BZE), codeine, morphine and 6-monoacethylmorphine (6-MAM) from human hair has been developed. The MSPD approach consisted of using alumina (1.80 g) as a dispersing agent and 0.6M hydrochloric acid (4 mL) as an extracting solvent. For a fixed hair sample mass of 0.050 g, the alumina mass to sample mass ratio obtained was 36. A previously conditioned Oasis HLB cartridge (2 mL methanol, plus 2 mL ultrapure water, plus 1 mL of 0.2M/0.2M sodium hydroxide/boric acid buffer solution at pH 9.2) was attached to the end of the MSPD syringe for on column clean-up of the hydrochloric acid extract and for transferring the target compounds to a suitable solvent for gas chromatography (GC) analysis. Therefore, the adsorbed analytes were directly eluted from the Oasis HLB cartridges with 2 mL of 2% acetic acid in methanol before concentration by N(2) stream evaporation and dry extract derivatization with N-methyl-tert-butylsilyltrifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS). The optimization/evaluation of all the factors affecting the MSPD and on column clean-up procedures has led to a fast sample treatment, and analytes extraction and pre-concentration can be finished in approximately 30 min. The developed method has been applied to eight hair samples from poli-drug abusers and measured analyte concentrations have been found to be statistically similar (95% confidence interval) to those obtained after a conventional enzymatic hydrolysis method (Pronase E). PMID:20817166
The major river systems originating from the Himalaya deposit arsenic bearing sediment into the deltas of South and Southeast Asia. High rates of sediment and organic carbon deposition combined with frequent flooding leads to anaerobic processes that release arsenic into the pore-water. Arsenic concentrations in the groundwater of these sedimentary basins are often above the World Health Organization drinking water standard of 10 ?g As L-1. As a result, 150 million people are at risk of chronic arsenic poisoning through water and rice consumption. The composition of the iron bearing phases hosting the arsenic in these deltaic sediments is poorly understood. Here we implemented a suite of selective chemical extractions to help constrain the types of arsenic bearing solidphases, which were complimented with synchrotron-based X-ray absorption spectroscopy and X-ray diffraction analyses to define the arsenic and iron mineralogy of the system. Sediment cores were collected in triplicate from a seasonally-inundated wetland in Cambodia at depths of 10, 50, 100, and 150 centimeters. We hypothesize that (i) arsenic will be predominantly associated with iron oxides, and (ii) the ratio of crystalline to amorphous iron oxides will increase with sediment depth (and age). We performed four selective extractions in parallel to quantify the various pools of arsenic. First, 1 M MgCl2 was used to extract electrostatically-bound arsenic (labile forms) from the sediment. Second, 1 M NaH2PO4 targeted strongly adsorbed arsenic. Third, 1 M HCl was used to liberated arsenic coprecipitated with amorphous Fe/Mn oxides, carbonates, and acid-volatile sulfides. Finally, a dithionite extraction was used to account for arsenic associated with reducible Fe/Mn oxides. Through this work, we identified the composition of the phases hosting arsenic at various depths through the soil profile, improving our understanding of how arsenic persists in the aquifer. In addition, defining the arsenic and iron mineralogy of the sediments will support more accurate modeling of arsenic reactivity, fate, and transport in deltaic systems.
In this study, the polystyrene-coated magnetic nanoparticles (MNPs/PSt) were successfully prepared and characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and vibrating sample magnetometry. The as-prepared MNPs/PSt were used as the adsorbent in magnetic solidphaseextraction of five pyrethroids, including lambda-cyhalothrin, deltamethrin, esfenvalerate, permethrin, bifenthrin, in environmental water samples. The five pyrethroids were determined by ultra fast liquid chromatography-ultraviolet spectrometry. The influencing factors, including amount of MNPs/Pst, extraction time, pH value, type and volume of desorption solvent and desorption time, were examined and optimized. The extraction recoveries obtained with merely 50mg of MNPs/Pst were very satisfactory. The whole extraction process could be completed within 0.5h. The MNPs/PSt can be reused after an easy washing process. Thus, a simple, green, economical, time saving and effective method for pyrethroids analysis in environmental water samples was established. A high enrichment factor of 500 was achieved and the limits of detection for lambda-cyhalothrin, deltamethrin, esfenvalerate, permethrin, bifenthrin were 0.015±0.001 ng mL(-1), 0.012±0.001 ng mL(-1), 0.026±0.001 ng mL(-1), 0.020±0.001 ng mL(-1), 0.013±0.001 ng mL(-1), respectively. Recoveries obtained by analyzing spiked water samples at three concentration levels (0.100±0.001 ng mL(-1), 1.000±0.001 ng mL(-1), 10.000±0.001 ng mL(-1)) were between 78.97±8.38% and 96.05±8.38%. The standard curves for the five pyrethroids showed good linearity with the correlation coefficients in the range of 0.9994-0.9999. The intra-day and inter-day precision were satisfactory with the RSDs in the range of 2.05-5.52% and 2.73-8.38%, respectively. PMID:22939157
Abstract A matrix-solidphase dispersion (MSPD) methodology has been developed to extract fenthion and its metabolites from olives and olive oils and compared with a conventional liquid-liquid extraction (LLE) procedure. The pesticide residues were analyzed by gas chromatography using a nitr...
An interlaboratory study with 8 locations was conducted to assess the stability of pesticides on solidphaseextraction disks (SPE) after incubation at various temperatures and time intervals. Deionized water fortified with selected pesticides was extracted using two types of SPE filtration disks...
An interlaboratory study was conducted to compare pesticide recovery of Empore' C18 and Speedisks' C18XF solid-phaseextraction disks. Four pesticides were used for the comparison of the two disk extraction materials: atrazine, diazinon, metolachlor, and tebuconzole. These pesticides were chosen ...
A method is presented for detection and quantitation of Roxarsone in poultry feed by liquid chromatography. The drug is extracted by phosphate buffer and determined by solidphaseextraction and reversed-phase liquid chromatography. Recoveries of the sample spikes and fortified field samples agree closely with those obtained by the standard spectrophotometric method. PMID:8241824
Different sample preparation steps prior to a detection method are often essential in analytical chemistry. In this thesis, both static extractions and on-line coupled solid-phaseextractions have been studied in combination with different detection techniques. Aspects of performing sample prepar...
Abstract A sensitive, simple and accurate method for the analysis of furan in roasted coffee has been used based on headspace-solid-phase micro-extraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). The extraction was performed using 75 ?m carboxen/polydimethyls...
Stir bar sorptive extraction (SBSE) is a technique for extraction and analysis of organic compounds in aqueous matrices, similar in theory to solidphase microextraction (SPME). SBSE has been successfully used to analyze several organic compounds, including food matrices. When compared with SPME, ...
A simple, sensitive, precise, and specific reverse HPLC method was developed and validated for the determination of plant hormones in barley (Hordeum vulgare L.). The method includes extraction in aqueous organic solvent followed by solid-phaseextraction, sample evaporation, and reversed-phase HPLC...
A method was developed for the confirmed identification and quantitation of 17B-estradiol, estrone, 17B-ethynylestrodial and 16a-hydroxy-17B-estradiol (estriol) in ground water and swine lagoon samples. Centrifuged and filtered samples were extracted using solidphaseextraction...
Alternaria and Stemphylium extracts were compared by means of various immunochemical and biologic methods. Skin-test responses to Alternaria and Stemphylium in allergic patients were positively correlated, and RAST binding values with the sera of 30 patients utilizing solid-phase Alt-I, Alternaria (70% ammonium sulfate--precipitable fraction), and Stemphylium allergens showed significant correlation, giving evidence for the presence of common allergenic determinants among these three extracts. In RAST inhibition assays, Alternaria and Stemphylium extracts exhibited dose-related inhibiton with solid-phase Stemphylium, Alternaria, and Alt-I, confirming the presence of Alt-I as the major shared allergenic fraction in the two extracts. In repetitive absorption experiments, both Alt-I and Alternaria solid-phase allergens absorbed Stemphylium-specific IgE antibodies from a 12-person serum pool. Similarly, Stemphylium solid-phase allergen absorbed both Alternaria- and Alt-I--specific IgE antibodies. Double-antibody radioimmunoassay for Alt-I showed higher Alt-I activity in Stemphylium than in Alternaria extract. In double-immunodiffusion experiments with rabbit anti--Alt-I antibodies, both Stemphylium and Alternaria extracts produced precipitin lines of identity with Alt-I. The antigenic relationship of the two crude extracts was further confirmed by crossed and crossed-line immunoelectrophoresis experiments. Our results showed that Alternaria and Stemphylium extracts contain multiple shared allergenic and antigenic determinants, including Alt-I. PMID:6183306
A simple, rapid, sensitive, specific and rugged method for the confirmation and quantitation of beta-lactam antibiotics in fortified and incurred bovine kidney tissue has been developed. The method uses a simple solvent extraction/deproteinization, dispersive solid-phaseextraction (dispersive-SPE)...
Highly porous polypyrrole (PPy)-nanocellulose paper sheets have been evaluated as inexpensive and disposable electrochemically controlled three-dimensional solidphaseextraction materials. The composites, which had a total anion exchange capacity of about 1.1 mol kg?1, were used for extraction and ...
6 pages, 3 figures, 3 tables.-- PMID: 16919644 [PubMed].-- Printed version published Nov 3, 2006. | A pressurized liquid extraction (PLE) solid-phaseextraction (SPE) gas chromatography–mass spectrometry (GC–MS) method was developed for the determination of two model organophosphorus pesticides (OPP...
The aim of this thesis was to develop analytical methods for measuring antimalarial drugs in biological fluids. Solidphaseextraction (SPE) was used for the enrichment and purification of the drugs. Automatic extraction procedures using a SPE robot were developed to reduce the workload for the a...
A new method for Ag determination in water samples using solidphaseextraction (SPE) coupled to a flow injection system and flame atomic absorption spectrometry was developed. The sorbent used for Ag preconcentration and extraction was the termite digestion product. Flow and chemical variables of t...
A quantitative method for the analysis of octyl- and nonylphenol, and their ethoxylates (1 to 5) in water and sediment is presented. Extraction procedures are based on solid-phaseextraction techniques. Identification and quantitation of the analytes is done by liquid chromatography coupled to tan...
A toxicity-directed method for fractionating non-polar organic toxicants using solid-phaseextraction (SPE) is described in phase II of EPA's "Methods for Aquatic Toxicity Evaluations". his method has been used very successfully to extract and fractionate acutely and chronically ...
This study developed and validated a method of measuring the feminizing chemicals 4-tert-octylphenol, 4-nonylphenol, nonylphenol monoethoxycarboxylate (NP(1)EC), nonylphenol monoethoxylate (NP(1)EO), nonylphenol diethoxylate (NP(2)EO), estrone, 17?-estradiol, estriol, 17?-ethinyl estradiol and bisphenol A in river water, sediment, and tissue using ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) and isotope-dilution techniques. Water samples were pretreated using disk-type automated solid-phaseextraction (SPE). Solid samples of sediment, fish, and clams were treated with matrix solid-phase dispersion (MSPD) using C(8) adsorbent. Eluents were directly passed following alumina cartridges for cleanup. The signal intensity of analytes on electrospray ionization (ESI) was compared with that of atmospheric pressure photoionization (APPI). The analytes were separated on a UHPLC C(18) column with aqueous 10-mM ammonium acetate for NPEOs and aqueous 10-mM N-methylmorpholine for the other compounds. On-line cleanup was evaluated using two-dimensional liquid chromatography (2-D LC). ESI could provide satisfactory response for all of the analytes. Though APPI did not offer suitable response for NP(1)EO, NP(2)EO and NP(1)EC, it provided better signal intensities for the steroid estrogens (1.0-2.4 times) and the phenols (3.2-4.4 times) than ESI. UHPLC shortened chromatographic time to less than 10 min. Disk-type automated SPE and MSPD dramatically increased the throughput of sample preparation. The extraction efficiency on surface water samples ranged from 10% to 91%. The extraction efficiency of MSPD on sediment, fish, and clams was 51-101%, 36-109%, and 30-111%, respectively. Acidic alumina cleanup was essential for the analysis of the tissue sample, and reduced matrix effects better than 2-D LC on-line cleanup. The limits of detection (LODs) in water ranged from 0.81 ng/L to 89.9 ng/L. The LODs in sediment and tissue ranged from tens of pg/g wet weight to only a few ng/g wet weight. This method proved to be accurate and reproducible, as both quantitative biases and relative deviations remained smaller than 20% at three spiked levels. PMID:22284486
A new tris(2-aminoethyl) amine (TREN) functionalized silica gel (SG-TREN) was prepared and investigated for selective solid-phaseextraction (SPE) of trace Cr(III), Cd(II) and Pb(II) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Identification of the surface modification was characterized and performed on the basis of FT-IR. The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 4, the maximum adsorption capacity of Cr(III), Cd(II) and Pb(II) onto the SG-TREN were 32.72, 36.42 and 64.61 mg g{sup -1}, respectively. The adsorbed metal ions were quantitatively eluted by 5 mL of 0.1 mol L{sup -1} HCl. Common coexisting ions did not interfere with the separation. According to the definition of International Union of Pure and Applied Chemistry, the detection limits (3{sigma}) of this method for Cr(III), Cd(II) and Pb(II) were 0.61, 0.14 and 0.55 ng mL{sup -1}, respectively. The relative standard deviation under optimum conditions is less than 4.0% (n = 11). The application of this modified silica gel to preconcentration trace Cr(III), Cd(II) and Pb(II) of two water samples gave high accurate and precise results.
Chronic exposure to high concentrations of arsenic (As) in windblown and vehicle-raised dust from tailings sites in Nova Scotia poses a potential health risk to recreational users of these areas and to nearby residents. The exposure may involve inhalation of dust, as well as oral ingestion of particles. It is important to understand the mineralogy and morphology of As-bearing dust particles in order to evaluate the risk posed by near-surface particulates in As-bearing tailings fields, as this will influence the stability and toxicity of As in the wastes. Optical mineralogy, scanning electron microscopy, electron microprobe, X-ray diffraction, synchrotron-based micro-X-ray diffraction ({mu}XRD) and micro-X-ray absorption near edge structure ({mu}XANES), and sequential leach extractions were applied to tailings samples from three sites in eastern Nova Scotia. Arsenic occurs naturally in these gold deposits mainly in arsenopyrite (FeAsS). In the near-surface material of the tailings fields, sulphide minerals have almost completely oxidized to secondary minerals such as scorodite (FeAsO{sub 4}{center_dot}2H{sub 2}O) and Ca-Fe arsenates. Iron oxyhydroxides contain variable amounts of As{sub 2}O{sub 5} from trace to 30 wt.% and CaO up to 8 wt.%. The presence of multiple As-hosting solidphases, including relatively soluble Ca-Fe arsenates and Fe oxyhydroxides with adsorbed As has important implications for human health risk assessment and remediation design.
In this paper, the potential applications of metal-organic framework (MOF) materials as fiber coatings for the solid-phase microextraction (SPME) of polycyclic aromatic hydrocarbons (PAHs) in water samples were explored. Fibers coated with MIL-53(Al, Cr, Fe) materials were fabricated by an adhesive method for SPME. The quantitation was performed by gas chromatography-tandem mass spectrometry (GC-MS/MS) using the multiple reaction monitoring mode. Among the three MIL-53(M) coatings, MIL-53(Al) showed the highest extraction efficiency towards PAHs under the current fabrication procedure. Under optimized conditions, the MIL-53(Al)-coated fiber showed good precision (relative standard deviation 0.98) for aqueous solutions containing 16 PAH . The fiber also offered high thermal and chemical stability. The method developed based on MIL-53(Al) SPME-GC-MS/MS was successfully applied in the analysis of real water samples. Based on the simulation results, the PAHs were adsorbed on MIL-53(Al) primarily through the hydrophobic and ?-? interactions between PAHs and the organic linker of the material. The results presented in this paper indicate that water-stable MOF materials have great potential for the SPME of aromatic compounds in water samples. PMID:23042089
Eleven organophosphorus compounds (OPs) that are used as plasticizers and flame retardants were analysed in duplicate samples of indoor air from 17 domestic and occupational environments. Solid-phaseextraction (SPE) columns were used as adsorbents and analysis was performed using GC with a nitrogen phosphorus selective detector. The total amounts of OPs in the air samples ranged between 36 and 950 ng m(-3); tris(chloropropyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) being the most abundant (0.4 to 730 ng m(-3)), followed by tributyl phosphate (0.5-120 ng m(-3)). Public buildings tended to have about 3-4 times higher levels of OPs than domestic buildings. The relative amounts of individual OPs varied between the sites and generally reflected the building materials, furniture and consumer products used in the sampled environments. Potential sources of these compounds include, inter alia, acoustic ceilings, upholstered furniture, wall coverings, floor polish and polyvinylchloride floor coverings. A correlation was observed between the TCEP concentrations in the air in the sampled environments and previously reported concentrations in dust, but no such correlation was seen for the heavier and less volatile tris(2-butoxyethyl) phosphate (TBEP). Based on estimated amounts of indoor air inhaled and dust ingested, adults and children in the sampled environments would be exposed to up to 5.8 microg kg(-1) day(-1) and 57 microg kg(-1) day(-1) total OPs, respectively. PMID:16049584
In recent years, bamboo charcoal, a new kind of material with special microporous and biological characteristics, has attracted great attention in many application fields. In this paper, the potential of bamboo charcoal to act as a solid-phaseextraction (SPE) adsorbent for the enrichment of the environmental pollutant perfluorooctanoic acid, which is one of the newest types of persistent organic pollutants in the environment, has been investigated. Important factors that may influence the enrichment efficiency--such as the eluent and its volume, the flow rate of the sample, the pH of the sample and the sample volume--were investigated and optimized in detail. Under the optimum conditions, the limit of detection for PFOA was 0.2 ng L(-1). The experimental results indicated that this approach gives good linearity (R(2) = 0.9995) over the range 1-1000 ng L(-1) and good reproducibility, with a relative standard deviation of 4.0% (n = 5). The proposed method has been applied to the analysis of real water samples, and satisfactory results were obtained. The average spiked recoveries were in the range 79.5-118.3%. All of the results indicate that the proposed method could be used for the determination of PFOA at ultratrace levels in water samples. PMID:18256812
Novel magnetic multi-walled carbon nanotubes@Fe(3)O(4) molecularly imprinted polymers (MWNTs@Fe(3)O(4)-MIPs) intended for bovine serum albumin (BSA) recognition were successfully developed. The MWNTs@Fe(3)O(4)-MIPs were characterized with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy images showed that the Fe(3)O(4) nanoparticles (diameter: 50-60 nm) were coated with a layer of MIPs with an average thickness of 25-30 nm. The magnetic material was easily dispersed and retrieved through the application of an external magnetic field. Adsorption experiments showed that the estimated maximum amount of BSA that could be adsorbed onto the MWNTs@Fe(3)O(4)-MIPs was 52.8 mg/g, and the time taken to reach equilibrium was about 40 min. Meanwhile, the MWNTs@Fe(3)O(4)-MIPs exhibited excellent selectivity towards (i.e., recognition of) BSA. The feasibility of the use of the MWNTs@Fe(3)O(4)-MIPs as a solid-phaseextraction (SPE) sorbent was evaluated, and the results showed that the MWNTs@Fe(3)O(4)-MIPs were able to separate the template protein BSA from a binary protein solution. The proposed sorbent based on MWNTs@Fe(3)O(4)-MIPs for BSA separation exhibited satisfactory recoveries ranging from 92.0% to 97.3% in real samples. It was also successfully used for the purification of BSA from bovine calf serum. PMID:21909663
Defence R and D Canada-Suffield (DRDC-Suffield) is responsible for analyzing samples that are suspected to contain chemical warfare agents, either collected by the Canadian Forces or by first-responders in the event of a terrorist attack in Canada. The analytical techniques used to identify the composition of the samples include gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy. GC-MS and LC-MS generally require solvent extraction and reconcentration, thereby increasing sample handling. The authors examined analytical techniques which reduce or eliminate sample manipulation. In particular, this paper presented a screening method based on solidphase microextraction (SPME) headspace sampling and GC-MS analysis for chemical warfare agents such as mustard, sarin, soman, and cyclohexyl methylphosphonofluoridate in contaminated soil samples. SPME is a method which uses small adsorbent polymer coated silica fibers that trap vaporous or liquid analytes for GC or LC analysis. Collection efficiency can be increased by adjusting sampling time and temperature. This method was tested on two real-world samples, one from excavated chemical munitions and the second from a caustic decontamination mixture. 7 refs., 2 tabs., 3 figs.
Sediments have been used to detect sources of contamination in a catchment of the Port Jackson (Sydney Harbour) estuary and to evaluate the effects of different land-use practices on the fluvial environment. Mean enrichment (mean concentrations over pre-anthropogenic background) of size-normalized (<62.5 {mu}m) aquatic sediment is 10 x for Cu, 20 x for Pb and 90 x for Zn adjacent to industrialized areas and 2 x, 7 x and 7 x, respectively for these metals in highly urbanized subcatchments. Diffuse sources contribute minor metals to fluvial sediment even in the most underdeveloped subcatchment (2 x, 3 x and 3 x for Cu, Pb and Zn respectively). Organochlorine pesticide residue concentrations parallel heavy-metal trends due to a common mixed industrial base. Effects-based sediment criteria suggest that some adverse biological impacts are probably occurring in streams flowing through the industrial areas. This interpretation is supported by sequential extraction data which show that a moderate proportion of total heavy metals, especially Zn, is associated with the more bioavailable exchangeable/adsorbed phases in these aquatic sediments. High total suspended solid loads in water downstream of one of the industrial centers, and high particle-bound Cu and Pb concentrations, suggest that most contaminants exiting the catchment do so in association with the solidphase. (orig.)
A solidphaseextraction method has been developed for the determination of copper, nickel and zinc ions in natural water samples. This method is based on the adsorption of copper, nickel and zinc on multiwalled carbon nanotubes (MWCNTs) impregnated with di-(2-ethyl hexyl phosphoric acid) (D2EHPA) and tri-n-octyl phosphine oxide (TOPO). The influence of parameters such as pH of the aqueous solution, amount of adsorbent, flow rates of the sample and eluent, matrix effects and D2EHPA-TOPO concentration have been investigated. Desorption studies have been carried out with 2 mol L(-1) HNO(3). The copper, nickel and zinc concentrations were determined by flame atomic absorption spectrometry. The results indicated that the maximum adsorption of copper, nickel and zinc is at pH 5.0 with 500 mg of MWCNTs. The detection limits by three sigma were 50 ?g L(-1) for copper, 40 ?g L(-1) for nickel and 60 ?g L(-1) zinc. The highest enrichment factors were found to be 25. The adsorption capacity of MWCNTs-D2EHPA-TOPO was found to be 4.90 mg g(-1) for copper, 4.78 mg g(-1) for nickel and 4.82 mg g(-1) for zinc. The developed method was applied for the determination of copper, nickel and zinc in electroplating wastewater and real water sample with satisfactory results (R.S.D.'s <10%). PMID:21041024
In the present study, a separation/preconcentration procedure for determination of aluminum in water samples has been developed by using a new atomic absorption spectrometer concept with a high-intensity xenon short-arc lamp as continuum radiation source, a high-resolution double-echelle monochromator, and a charge-coupled device array detector. Sample solution pH, sample volume, flow rate of sample solution, volume, and concentration of eluent for solid-phaseextraction of Al chelates with 4-[(dicyanomethyl)diazenyl] benzoic acid on polymeric resin (Duolite XAD-761) have been investigated. The adsorbed aluminum on resin was eluted with 5 mL of 2 mol L(-1) HNO(3) and its concentration was determined by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Under the optimal conditions, limit of detection obtained with HR-CS FAAS and Line Source FAAS (LS-FAAS) were 0.49 ?g L(-1) and 3.91 ?g L(-1), respectively. The accuracy of the procedure was confirmed by analyzing certified materials (NIST SRM 1643e, Trace elements in water) and spiked real samples. The developed procedure was successfully applied to water samples. PMID:22740156
A novel and effective dispersive solid-phaseextraction (dSPE) procedure with rapid magnetic separation using ethylenediamine-functionalized magnetic polymer as an adsorbent was developed. The new procedure had excellent clean-up ability for the selective removal of the matrix in red wine. An accurate, simple, and rapid analytical method using ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) for the simultaneous determination of nine food additives (i.e., acesulfame, saccharin, sodium cyclamate, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid, and neotame) in red wine was also used and validated. Recoveries ranging from 78.5% to 99.2% with relative standard deviations ranging from 0.46% to 6.3% were obtained using the new method. All target compounds showed good linearities in the tested range with correlation coefficients (r) higher than 0.9993. The limits of quantification for the nine food additives were between 0.10?g/L and 50.0?g/L. The proposed dSPE-UFLC-MS/MS method was successfully applied in the food-safety risk monitoring of real red wine in Zhejiang Province, China. PMID:23044217
A simple solidphaseextraction system based on the applying the nickel-aluminum layered double hydroxide (Ni-Al LDH) as a nano-sorbent was developed for the speciation analysis of chromium and manganese by flame atomic absorption spectrometry (FAAS). The method is based on the fact that Cr(VI) and Mn(VII) oxyanions could be adsorbed on the Ni-Al(NO(3)(-)) LDH and/or exchanged with LDH interlayer NO(3)(-) ions at pH 6.0, whereas Cr(III) and Mn(II) cations pass through the LDH-packed column without retention. The determinations of total Cr and Mn, and hence indirectly Cr(III) and Mn(II), involve the pre-oxidations of Cr(III) and Mn(II) to Cr(VI) and Mn(VII) with H(2)O(2) and acidic solution of KIO(4), respectively. Several important factors affecting the retention efficiency were investigated and optimized. In the optimum experimental conditions, the limits of detection (3S(b)/m) for Cr(VI) and Mn(VII) were 0.51 and 0.47 ng mL(-1), and the relative standard deviations were 2.5 and 3.2% (C=30.0 ng mL(-1), n=6), respectively. The presented method was validated by the analysis of a certified reference material, and applied to the speciation of Cr and Mn in drinking waters, surface waters and industrial wastewater effluents. PMID:22608436
A simple, convenient and high selective molecularly imprinted matrix solid-phase dispersion (MI-MSPD) using water-compatible cyromazine-imprinted polymer as adsorbent was proposed for the rapid screening of melamine from bovine milk coupled with liquid chromatography-ultraviolet detection. The molecularly imprinted polymers (MIPs) synthesized by cyromazine as dummy template and reformative methanol-water system as reaction medium showed higher affinity and selectivity to melamine, and so they were applied as the specific dispersant of MSPD to extraction of melamine and simultaneously eliminate the effect of template leakage on quantitative analysis. Under the optimized conditions, good linearity was obtained in a range of 0.24-60.0?gg(-1) with the correlation coefficient of 0.9994. The recoveries of melamine at three spiked levels were ranged from 86.0 to 96.2% with the relative standard deviation (RSD)?4.0%. This proposed MI-MSPD method combined the advantages of MSPD and MIPs, and could be used as an alternative tool for analyzing the residues of melamine in complex milk samples. PMID:23040986
A simple approach has been developed for the solidphaseextraction of chromium(VI) based on the adsorption of its ion-association complex with cetyltrimethylammoniumbromide (CTABr) on an alumina column. The effect of various parameters such as acidity, stability of the column, sample volume, effect of diverse ions, etc. have been studied in detail. The adsorbed complex could be eluted using sodium hydroxide and the concentration of chromium has been established using visible spectrophotometry after complexation with diphenyl carbazide. The calibration graph was linear in the range 0-0.5 microg mL(-1) chromium(VI) with a detection limit of 5 microg L(-1). A highest preconcentration factor of 25 could be obtained for 250 mL sample volume. The data from the column studies were also studied using the Thomas model of adsorption. The experimental results obtained were correlated with the proposed model of adsorption. The Thomas rate constant k was found to be 0.0025 L/min mg and the maximum adsorption capacity q(o) was found to be 0.36 mgCr/g alumina at an initial chromium(VI) concentration of 1 mg L(-1). The validity of the method has been checked by applying it to study the recovery of chromium in spiked water samples and electroplating wastewater. PMID:17126483
For cleanup of animal fat before GC analysis of organochlorine pesticides and polychlorinated biphenyls, freezing-lipid filtration with solid-phaseextraction and matrix solid-phase dispersion were evaluated to replace the official Brazilian methodology that uses preparative alumina column chromatography. General drawbacks associated with this last technique, such as the use of large amounts of solvent, laborious and time-consuming procedure could be avoided by using these alternative approaches. Experiments were carried out to study the performance by using different combinations of sorbents and elution solvents. Efficiency of alternative extraction methods in terms of fat removal and recovery capability was monitored by gravimetry, TLC, and GC with electron capture detection. Freezing-lipid filtration with solid-phaseextraction afforded better clean up efficiency with recoveries in a range of 54.5 to 103.6% with the relative standard deviation of less than 10% for all compounds under investigation. PMID:22833512
The potential of microwave-assisted liquid–liquid and solidphaseextraction coupled with fluorescence spectroscopy and employing one- to three-way spectral data was assessed in terms of their capacity for the rapid detection of heavy polycyclic aromatic hydrocarbons (PAHs) in olive and sunflower oils. Tocopherols and pigments groups (chlorophyll and pheophytin) present in oil matrices were the main interference compounds in the detection of PAHs using fluorescence spectroscopy. Partial spectral overlap and inner-filter effects were observed in the emission range of the analytes. The effectiveness of removing these interferences using solidphaseextraction (silica, C18 and graphitized carbon black) was examined. Solidphaseextraction with silica was the most effective method for ...
The concentrations of eighteen perfluorinated compounds (PFCs: C5-C14 carboxylates, C4, C6-C8 and C10 sulfonates and 3 sulfonamides) were determined in wastewater and sludge samples originating from two different wastewater treatment plants (WWTPs). The analytes were extracted by solidphaseextraction (dissolved phase) or sonication followed by solidphaseextraction (solidphase). Qualitative and quantitative analyses were performed by LC-MS/MS. According to the results, perfluoropentanoic acid (PFPeA), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were dominant in wastewater and sludge samples from both plants. The average concentrations in the raw and treated wastewater ranged up to 75.7ngL^-^1 (perfluorotridecanoic acid, PFTrDA) and 76.0ngL^-^1 (PFPeA), respective...
Solid-phase nanoextraction is a sample preparation technique, which combines nanotechnology with analytical chemistry, and brings analytical chemistry to a higher level, particularly for complex system analysis. This paper describes a typical example of electrochemical solid-phase nanoextraction and electrochemical detection. Trace amounts of copper (5.0?×?10?13?mol/L) were extracted by electrochemical solid-phase nanoextraction on to the magnesium oxinate nanoparticle-modified carbon paste electrode surface in a pH?7.2 phosphate buffer system at ?0.50 V for 100 s. The extraction is achieved by the cation exchange between copper(II) in the aqueous solution and magnesium(II) from the magnesium oxinate nanoparticles on the electrode surface. The extracted copper shows an irreversible anodic ...
Nitrosamines are a group of carcinogens that have been found in various latex products. Methods have been developed for extraction, concentration and detection of simulant migration of volatile nitrosamines from latex gloves and balloons. After glove samples or balloon samples were treated with artificial sweat and artificial saliva, headspace solid-phase microextraction and gas chromatography with mass spectrometer detection were performed. Eight volatile nitrosamines were extracted by a fused silica fiber coated with carboxen-polydimethylsioxane, and solid-phase microextraction conditions were optimized. The developed method was successfully used to analyze simulant migration of volatile nitrosamines from latex gloves and balloons. The described methods are rapid and simple, with adequat...
A simple and economic solid-phaseextraction coupled with UV/Vis spectrophotometric method is described for the analysis of ibuprofen and ciprofloxacin. Following solid-phaseextraction from model wastewater samples containing standard ibuprofen or ciprofloxacin, elutes were analyzed by a UV/Vis spectrophotometer at 225 nm for ibuprofen and 280 nm for ciprofloxacin. The assay was linear for both compounds with good coefficients of correlation. This method shows good recoveries for both compounds with 101.0 ± 9.8% for ibuprofen and 99.4 ± 11.8% ciprofloxacin.
A simple and economic solid-phaseextraction coupled with UV/Vis spectrophotometric method is described for the analysis of ibuprofen and ciprofloxacin. Following solid-phaseextraction from model wastewater samples containing standard ibuprofen or ciprofloxacin, elutes were analyzed by a UV/Vis spectrophotometer at 225 nm for ibuprofen and 280 nm for ciprofloxacin. The assay was linear for both compounds with good coefficients of correlation. This method shows good recoveries for both compounds with 101.0â??±â??9.8% for ibuprofen and 99.4â??±â??11.8% ciprofloxacin.
Abstract Several new methods have been developed recently that allow the direct detection of lipids without resorting to derivatization or chromatographic separation. The simplest of these is direct MALDI (matrix-assisted laser desorption/ionization) mass spectrometry. This approach is most useful for mixtures that contain minimal amounts of ion-suppressing interfering components. However, when such components are present, their effects can often be minimized by using simple separation techniques beforehand, such as solidphaseextraction or thin layer chromatography. For example, direct MALDI has been used for rapid screening of lipids and taxonomic identification of the source organisms with no sample pretreatment. Collecting fractions from solidphaseextraction cartridges have also bee...
Boron (B) is a potentially plant toxic ion and is present in domestic treated wastewater (reclaimed water) in Jordan in concentrations of around 1 mg L-1. As reclaimed water is used for irrigation in Jordan the concentration of B gives potential for detrimental effects on crop productivity. Such effects are dependent on the crop type and importantly, the concentration of B in the soil solution and on the readily exchanged component of the soil solidphase. Boron also behaves complexly in soil because it has sorbing tendencies. The sorption of B onto the soil solidphase removes it from solution and effectively reduces its toxicity potential to crops. However, desorption raises its availability in the soil solution and increases the potential for toxicity effects. To investigate B sorption behaviour in Jordanian soils, experimental work was conducted to describe how B sorption and desorption is affected by the concentration of B in the soil solution. Boron isotherms (to show the amount of B sorbed onto the soil surface relative to the amount of B remaining in the soil solution at constant pressure and temperature) were created which showed that the soil had a high affinity to adsorb B and that desorption of B occurs as the concentration of the soil solution is reduced (for example, through the addition of freshwater) to create a new equilibrium between the concentration of B in the soil solution and the amount of B sorbed onto the soil particles. This suggests that freshwater inputs to soil to which B has previously sorbed onto the soil solidphase during irrigation with reclaimed water will lead to the desorption of B, possibly raising the concentration in the soil solution. To test this hypothesis, the B concentration in the soil solution (B in the soil saturation paste extract) of soils irrigated with reclaimed water was determined. This work confirmed that soils to which a greater volume of reclaimed irrigation water had been applied had a higher concentration of B in the soil solution compared to soils to which less water had been applied. The difference was particularly noticeable when the concentration of B was compared to the concentration of non-sorbing chloride in the soil. Boron concentration was also determined by the established method of mannitol calcium chloride abstraction to give both the soluble and specifically and non-specifically sorbed B in the soil. This analysis showed good correlation between the concentration of B in the soil saturation extract and the concentration of B abstracted by mannitol calcium chloride. This correlation effectively describes the proportion of B in the soil which is soluble (determined in the saturation extract) and that which is readily desorbed (the concentration of B abstracted with mannitol calcium chloride minus the concentration in the saturation extract). Further work is needed into this relationship as it could offer a means by which the adsorption capacity of the soil can be rapidly appraised and the leaching requirement (the amount of water needed to desorb and transfer the B through the soil) can be better predicted.
Multiplexed colorimetric solid-phaseextraction (MC-SPE) is an extension of colorimetric solid-phaseextraction (C-SPE) an analytical platform that combines colorimetric reagents, solidphaseextraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phaseextraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).
An analytical method was developed to quantitatively determine pharmaceuticals in biosolid (treated sewage sludge) from wastewater treatment plants (WWTPs). The collected biosolid samples were initially freeze dried, and grounded to obtain relatively homogenized powders. Pharmaceuticals were extracted using accelerated solvent extraction (ASE) under the optimized conditions. The optimal operation parameters, including extraction solvent, temperature, pressure, extraction time and cycles, were identified to be acetonitrile/water mixture (v/v 7:3) as extraction solvent with 3 extraction cycles (15min for each cycle) at 100^oC and 100bars. The extracts were cleaned up using solid-phaseextraction followed by determination by liquid chromatography coupled with tandem mass spectrometry. For the...
Humic acid (HA) which originated from Leonardite was purified and immobilized onto aminoprophyl silica (APS). Afterwards, the remaining amino groups on the silica are successfully end-capped using acetic anhydride in DMF media and this material was used for Cu(II) ions removal from aqueous solution by using continuously solidphaseextraction (SPE) technique in a column arrangement. The sorption characteristics of Cu(II)-immobilized humic acid (ImHA) system were investigated at various experimental conditions, and output was observed by a UV detector. All solidphaseextraction (SPE) steps were monitored through breakthrough curves used to visualize distribution of Cu(II) concentration between mobile phase and solidphase. In addition to this, the solutions collected from stripping steps w...
An extraction chromatographic material for extracting metal cations from a iquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methanediphosphonic acid on an inert particulate support.
An extraction chromatographic material for extracting metal cations from a liquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methanediphosphonic acid on an inert particulate support.
The effectiveness of four extraction methods (modified QuEChERS, matrix solid-phase dispersion (MSPD), solid–liquid extraction (SLE) and solid-phaseextraction (SPE) clean-up) were evaluated for simultaneous determination of 32 mycotoxins produced by the genus Fusarium, Claviceps, Aspergillus, Penicillium and Alternaria in barley by ultra high pressure liquid chromatography coupled to ultra-high resolution mass spectrometry (UHPLC-Orbitrap® MS). The efficiency and efficacy of extraction methods were evaluated and compared in number of extracted mycotoxins and obtained recoveries. From the one point of view, QuEChERS procedure was fast and easy, as well as it was able to successfully extract all selected mycotoxins. On the other hand, SLE method, MSPD and SPE clean-up method...
State-of-the-art methods of the extraction, preconcentration, and determination of quercetin and other flavonoids are described. Different methods of sample preparation of real samples are compared, including solvent extraction from solid matrices and liquid-liquid, supercritical fluid, and solid-phaseextraction. The following main determination methods are discussed: HPLC, thin-layer chromatography, capillary electrophoresis, spectrophotometry, luminescence, and electrochemical methods. Some examples of quercetin determination in biological fluids, food products, biologically active food supplements, pharmaceutical preparations, and plant samples are given.
Spectrometric techniques for the analysis of trace cadmium have developed rapidly due to the increasing need for accurate measurements at extremely low levels of this element in diverse matrices. This review covers separation and preconcentration procedures, such as electrochemical deposition, precipitation, coprecipitation, solidphaseextraction, liquid-liquid extraction (LLE) and cloud point extraction (CPE), and consider the features of the their application with several spectrometric techniques.
The extraction of uranium from seawater involves adsorption, desorption, concentration and separation, of which the adsorption stage requires most development; uranium concentration in seawater is very low, its amount handled being extremely large. The authors have developed a metal-containing hydroxide - active carbon composite adsorbent and an AO resin adsorbent for uranium extraction from seawater. The following are described: the development of inorganic adsorbents - the preparation of a metal-containing hydroxide - active carbon adsorbent, the forming of a titanium - active carbon composite adsorbent, the extraction of uranium from seawater with a composite adsorbent; the development of organic adsorbents - the preparation of AO resin and uranium adsorption; the extraction of uranium from seawater with AO resin, the preparation of fibrous and bead-fibrous AO resin. (Mori, K.).
A simple and inexpensive liquid chromatography-tandem mass spectrometric method for the determination of anthelmintics in alfalfa plants (Medicago sativa L.) was developed and validated. Anthelmintics in plant leaves and stems (green chops) were extracted with methanol/acetonitrile (7:3, v/v) followed by a concentration and clean-up step using solid-phaseextraction (Strata-X, 500?mg, 6?ml cartridge). After drying with nitrogen gas, the adsorbed analytes were eluted with methanol/acetonitrile (50:50, v/v) mixture followed by 100% acetonitrile. Chromatographic separation was achieved on an Atlantis T-3 (2.1?×?100?mm?×?3?µm) analytical column with a Phenomenex guard cartridge (C8, 4?×?3?mm) attached to a Waters triple quadrupole mass spectrometer operated in positive electrospray ionisation mode with selected reaction monitoring. Samples were analysed using gradient elution at a flow rate of 0.35?ml?min(-1). The mobile phase consisted of a 10?mM ammonium formate solution in (A) water/acetonitrile (90:10, v/v) and (B) methanol/acetonitrile (50:50, v/v). The method was validated for levamisole, fenbendazole, fenbendazole sulphoxide and fenbendazole sulphone at 10, 20 and 40?µg?kg(-1) and for eprinomectin at 20, 40 and 80?µg?kg(-1). Limits of quantification (LOQ) were 10?µg?kg(-1) for all analytes except eprinomectin, which had an LOQ of 20?µg?kg(-1). The overall mean recovery in green plants was between 74.2% and 81.4% with repeatabilities ranging from 2.2% to 19.1% and reproducibilities in the range 3.8-8.7%. The validated method was applied to plant samples in a study on the behaviour of anthelmintic drugs in a soil, plant and water system. PMID:22827314
A matrix solid-phase dispersion (MSPD) method for the simultaneous determination of 20 organochlorine pesticides (OCPs) (aldrin, endrin, dieldrin, ?-BHC, ?-BHC, ?-BHC, ?-BHC, ?-chlordane, ?-chlordane, p,p'-DDE, p,p'-DDT, p,p'-DDD, endosulfan I, endosulfan II, endosulfan sulfate, endrin aldehyde, heptachlor, heptachlor epoxide, endrin ketone and methoxychlor) and six polychlorinated biphenyl (PCB) congeners (PCB 28, 52, 101, 138, 153 and 180) in post-mortem human lung has been developed and validated. Response surface methodology (RSM) and desirability function were employed to optimize the extraction conditions of MSPD. Extraction was carried out using Florisil (2.0 g) as the sorbent material as well as clean-up adsorbent (1.5401 g), n-hexane:dichloromethane (11:89, v/v) as the eluting solvent (15.45 mL) and Na?SO? (2.0 g) as dehydrating agent. Determination and quantification of OCPs and PCBs residues were carried out using a gas chromatograph equipped with an electron capture detector (GC-ECD). A mass spectrometric detector (GC-MS) in the selected ion monitoring (SIM) mode was also used for confirmation purposes. Method detection limits by GC-MS ranged from 0.42 to 0.87 ng g?¹ and 0.51 to 1.35 ng g?¹, for OCPs and PCBs, respectively. Lower detection limits were calculated for GC-ECD ranging between 0.15-0.30 ng g?¹ and 0.18-0.48 ng g?¹, respectively. Relative standard deviations did not exceed 9%. Analytes provided recoveries ranging from 65% to 106%. The proposed method was successfully applied to the analysis of lung tissues from six autopsy cases. PMID:22265777
An analytical method for the determination of the major endogenous and exogenous estrogenic steriods in effluent water samples of sewage treatment plants (STPs) with a LOQ down to 1 ng/L and below has been developed. The exogenous estrogen 17alpha-ethynylestradiol, frequently used as estrogenic component in oral contraceptives, and the endogenous estrogen 17beta-estradiol show the highest estrogenic potential, therefore they were part of our target compounds. In addition, the content of the synthetic gestagen levonorgestrel, also often administered in oral contraceptives, was determined. A solid-phaseextraction system for high volume sampling of water up to 25 L was implemented. Two types of adsorbent, Amberlite XAD 2 and a mixture of LiChrolut EN/Bondesil C-18, respectively, were tested for their extraction efficiency of these polar analytes. Recovery rates with LiChrolut EN/Bondesil C-18 ranged up to 94%, whereas sampling on XAD 2 led only to poor recoveries below 40%. After a liquid chromatographic clean-up step on silicagel the steroids were converted into their trimethylsilyl-ethers by the reaction with MSTFA/TMSI (N-methyl-N-trimethylsilyl-2,2,2-trifluoroacetamide, trimethylsilyliodide) and were then determined by HRGC/MS in the selected ion mode. A limit of quantification over the whole procedure of at least 1 ng/L was reached for all analytes. In several effluent samples the input of estrogens by the STP of the cities Ulm and New Ulm into the river Danube was characterised. The concentrations commonly found ranged from 1 ng/L up to 13 ng/L, depending on the respective steroid. PMID:11220326
Non-steroidal anti-inflammatory drugs are widespread employed in both human and animal health care to reduce ongoing inflammation, pain and fever due to their anti-inflammatory, analgesic and, antipyretic actions. Apart from the well-known biological samples, nowadays these compounds are frequently found in the environment, leading to longterm exposure resulting in adverse effects on humans and wildlife. Therefore, it is important to develop analytical methodologies to detect and control the presence of these pharmaceuticals in very different kinds of samples, from urine, serum or plasma, to river and waste water, sediments or sewage sludge, most of them having very complex matrices. Other problems to solve are the low concentration of the target analytes, the presence of a great number of potential interferences and, sometimes, incompatibilities with the detection systems. Consequently, sample pre-treatment is a very important step to take into account in the non-steroidal anti-inflammatory drugs determination. Herein we reviewed the main extraction and clean-up procedures reported in the literature for these substances: ultrasonic extraction, Soxhlet extraction, pressurized- liquid extraction, supercritical fluid extraction, microwave-assisted extraction, dispersive liquid-liquid microextraction, hollow fiber liquid phase microextraction, pressurized hot water extraction, solid-phaseextraction, molecularly imprinted solid-phaseextraction and solid-phase microextraction. Several analytical methodologies have been developed to quantify non-steroidal anti-inflammatory drugs, including gas chromatography-mass spectrometry, liquid chromatography with ultraviolet detection, diode array detection, fluorescence detection and tandem mass spectrometry. PMID:22934746
This paper reports a method for the determination of zinc in Brazilian sugar cane spirit, (cachaça in Portuguese), using solid-phaseextraction with a flow injection analysis system and detection by FAAS. The sorbent material used was activated carbon obtained from Moringa oleifera husks. Flow and ...
Dec 30, 1987 ... systems. Recombinant. DNA. CrDNA) techno!oRY, one of the new techniques, allows direct ... DNA technology can be used in a wide variety of industrial sectors to develop ...... automated techniques. ...... corn yield enhancer ... chromatography,. DNA and protein synthesis, solidphaseextraction columns ...
Jan 15, 2009 ... Incidents of abnormally high silver in Rodnik water from 10 P (Dec 02) and. 11P ( Apr 03). • High turbidity ... Lead in filter reactor effluent, although no apparent breakthrough to potable .... Be prepared for unexpected challenges! *Trapped air ... C-SPE utilizes solidphaseextraction membranes impregnated ...
Solid-phaseextraction with Tenax® is one of the most used methods for determining the fraction of a pollutant that desorbs rapidly from sediment and thus is available for living beings. In the present study, this technique has been applied to sediment contaminated in the laboratory with polybromina...
The removal of atrazine from water by a solidphaseextraction technique usinginsoluble polymers is described. Porous crosslinked polymers bearing piperazine moieties were prepared in a one step reaction from the precursor 4-nitrophenylacrylate incorporating polymers (PolyHIPE type prepared by the p...
Abstract in english Fundamental aspects of SolidPhase Micro-Extraction (SPME) are discussed in the present paper. The application of SPME as a microtechnique of sample preparation for gas chromatographic analysis is considered and related to existing theoretical models. Both research prototypes and commercial SPME devices are considered.
Solidphase microextraction (SPME) is applied in the dynamic speciation analysis of the pesticide atrazine in an aqueous medium containing sorbing latex nanoparticles. It is found that the overall rate of extraction of the analyte is faster than in the absence of nanoparticles and governed by the co...
A novel sorbent in solidphase microextraction (SPME) method based on poly(3-alkylthiophenes) was used in the isolation of linezolid from human plasma samples following liquid chromatography determination. The effect of extraction time on the sorption capacity of the SPME process was studied and poi...
8 pages, 3 figures. | Headspace solid-phase microextraction (HS-SPME), simultaneous distillation/extraction (SDE) and closed-loop stripping analysis (CLSA) coupled to gas chromatography/mass spectrometry (GC/MS) were used to study virgin olive oil, with the goal of detecting large numbers of charact...
A new method is described for determining total gasoline-range organics (TGRO) in water that combines solid-phase microextraction (SPME) and infrared (IR) spectroscopy. In this method, the organic compounds are extracted from 250-mL of water into a small square (3....
10 pages, 6 figures, 2 tables.-- PMID: 16824536 [PubMed].-- Printed version published Aug 18, 2006.-- Issue title: ExTech 2006 - 8th International Symposium on Advances in Extraction Techniques (York, UK, Feb 6-8, 2006). | Photo-solid-phase microextraction (photo-SPME) is combined for the first time...
5 pages, 4 figures.-- PMID: 17936289 [PubMed].-- Printed version published on Dec 7, 2007. | Issue title: ExTech 2007 - 9th International Symposium on Advances in Extraction Technologies (Alesund, Norway, June 3-6, 2007). | Aqueous-phase alkylation followed by, headspace solid-phase microextraction ...
A new method is described for determining nitroaromatic compounds in water that combines solid-phase microextraction (SPME) and infrared (IR) spectroscopy. In this method, the compounds are extracted from a 250-mL volume of water into a small square (3.2 cm ? 3.2 cm ? 61.2...
Heterocyclic aromatic amines (HAAs) are animal carcinogens and suspected human carcinogens which are formed in cooked foods at the low parts per billion level. HAAs in cooked meats were purified by either immunoaffinity chromatography or solidphase tandem extraction, which allowed for the simultane...
An analytical method for the determination of voriconazole (UK-109,496; Pfizer) in plasma was developed and validated. The method utilizes solid-phaseextraction technology and high-performance liquid chromatography. The lower limit of quantitation is 0.2 ?g/ml, and the range of linearity tested was...
The application of analytical and semi-preparative columns in reversed-phase liquid chromatography-solid-phaseextraction-nuclear magnetic resonance (HPLC-SPE-NMR) was compared. The work was aiming at separating a higher sample amount in a single run and in this way to reduce the necessary NMR measu...
A new Fe3O4/poly(divinylbenzene-co-methacrylic acid) core-shell magnetite microspheric material have been successfully developed as magnetic-mediated solid-phaseextraction micro-particle sorbent in dispersion mode (MM-SPE-MP) for the determination of selected estrogenic endocrine disrupting chemica...
The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phaseextraction (using primary–secondary amine and graphitized carbon black) and large-volume (20 ?L) injecti...
The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phaseextraction (using primary¿secondary amine and graphitized carbon black) and large-volume (20 ¿L) injecti...
The use of headspace solid-phase microextraction (HS-SPME) to determine benzene, toluene, ethylbenzene, and xylenes (BTEX) in foundry molding sand, specifically a 'green sand' (clay-bonded sand) was investigated. BTEX extraction was conducted using a 75'M Carboxen-polydimethylsiloxane (CAR-PDMS) fi...
This thesis describes bioanalytical methods for measuring melatonin and some anti-infective drugs in biological fluids. Solid-phaseextraction (SPE) or protein precipitation was used for enrichment and purification of the analytes and Liquid Chromatography (LC) was used to analyze the samples. Devel...
A novel solidphase microextraction fibre consisting of a sorbent Xiks-1 fixed on a stainless steel support is presented for the extraction of fatty acid derivatives. The sorbent is incorporated into a slot. The sorbent particles do not contact with the outer needle and thus the mechanical damage of...
The volatile fraction obtained at room temperature has been studied by GC-MS after solid-phase micro-extraction (SPME). the endogeneous compounds derived from lipid peroxidation were predominant in pork and duck, while carbon disulphide and an alogenated contaminant were predominant in goose.
In this study, a method for the determination of low concentrations of lead in beer samples using solid-phaseextraction with a flow injection analysis system and detection by flame atomic absorption spectrometry (FAAS) was developed. Moringa oleifera seeds were used as a biosorbent material. Chemic...
Hydrochloric acid processing is an effective method for increasing productivity of wells, for clearing the critical zone of the stratum from the solidphase and for increasing permeability. It is one of the basic methods for intensifying the extraction of oil at the Aktyube deposit.
The present study was designed to evaluate the inhibitory effect of nutmeg (Myristica fragrans Houtt.) seed essential oil on the locomotor activity of mice in a wheel cage. Active compounds in the essential oil were identified by off-line solidphaseextraction (SPE-C18) and GC/MS analysis. The esse...
Recently, several laboratory methods have been developed for the prediction of contaminant bioavailability. So far, none of these methods has been extensively tested for petroleum hydrocarbons. In the present study we investigated solid-phaseextraction and persulfate oxidation for the prediction of...
This progress report describes accomplishments of four programs. The four programs are entitled (1) Faster,simpler processing of positron-computing precursors: New physicochemical approaches, (2) Novel solidphase reagents and methods to improve radiosynthesis and isotope production, (3) Quantitative evaluation of the extraction of information from PET images, and (4) Optimization of tracer kinetic methods for radioligand studies in PET.
This progress report describes accomplishments of four programs. The four programs are entitled (1) Faster,simpler processing of positron-computing precursors: New physicochemical approaches, (2) Novel solidphase reagents and methods to improve radiosynthesis and isotope production, (3) Quantitative evaluation of the extraction of information from PET images, and (4) Optimization of tracer kinetic methods for radioligand studies in PET.
Data is presented showing the progress made towards the development of a new automated system combining solidphaseextraction (SPE) with gas chromatography/mass spectrometry for the single run analysis of water samples containing a broad range of acid, base and neutral compounds...
The cis-syn-cis isomer of the crown ether DCH18C6 is used in solution in an organic diluent such as benzonitrile or dichlorethane, or on a solidphase such as silica. The use of this isomer increases the extraction ratio of plutonium and strontium of solution from spent fuel reprocessing or from aqueous effluents containing Sr or Pu.
The objective of this work was to know the occurrence of OTA in organic and non-organic cereals and cereal products from Spain and Portugal. A method based on extraction with matrix solidphase dispersion (MSPD) using octylsilica (C8) followed by liquid chromatography coupled with fluorescence detec...
A nontargeted, comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GCxGC-TOFMS) method was developed for the analysis of fermented cucumber volatiles before and after anaerobic spoilage. Volatiles extracted by solid-phase microextraction were separated on a polyethyle...
The application of an acid digestion and subsequent solid-phaseextraction (SPE) procedure were implemented as preliminary treatments prior to quantifying the levels of potentially endocrine disrupting metals (EDMs) in a variety of solid and liquid matrices. These included (solid) river sediment, l...
Applications of solid-phaseextraction for the isolation of certain lipid classes prior to chromatographic analysis are given. More information was found for sterols and related compounds, polar phenols and contaminants such as polycyclic aromatic hydrocarbons. Detailed analytical protocols are presented and discussed in many cases. (Author) 120 refs.
The distribution of 17 pharmaceuticals between water and the solidphase (sediments and soils) was studied by utilizing solid-phaseextraction (SPE) and liquid chromatography?tandem mass spectrometry (LC-MS/MS). Two extraction procedures for soils and sediments, prior to the SPE, one based on pressurized liquid extraction (PLE) with hot water and the other on methanol/water ultrasonic extraction, were compared. Absolute recoveries were 71.2?99.3% [relative standard deviation (RSD) <21.4%)] for water, and the method detection limits (MDLs) ranged from 0.3 to 10 ng L?1. Recoveries were 35.4?105.3% (RSDs <19.1%) and 42.1?97.8% (RSDs <14%) for soil and sediment samples, respectively, using PLE and 20.2?86.5% (RSDs <25.1%) and 30.3?97.4% (RSDs <19.1%) using ultrasonic extraction. Fifteen of the...
This work describes solid-phaseextraction–ultra-performance liquid chromatography with electrospray ionization tandem spectrometry for determination of malachite green and metabolite leucomalachite green, crystal violet and metabolite leucocrystal violet, methylene blue and metabolites including azure A, azure B and azure C in aquatic products. Samples were extracted with acetonitrile and ammonium acetate buffer and purified by liquid extraction with dichloromethane, and then on MCAX solid-phaseextraction cartridges. Then the extract was evaporated at 45°C by nitrogen blow. The residue was dissolved and separated by an Acquity BEH C18 column. The mobile phase was acetonitrile (A) and 5 mmol/L of ammonium acetate containing 0.1% formic acid (B). Analytes were confirme...
The properties of various adsorbents for uranium extraction from seawater are measured under standardized experimental conditions. It turns out that fractionated humic acids have exceptionally fast loading kinetics. This property leads to a substantial reduction of capital investments in conventional adsorbent bed techniques as well as in a procedure designed to avoid large adsorbent bed constructions by using carrier bodies in the open sea.
Abstract Ultrasound assisted matrix solidphase dispersion (MSPD) was applied to isolate eight cephalosporins (cefadroxil, cefaclor, cephalexin, cefotaxime, cefazolin, cefuroxime, cefoperazone and ceftiofur) from milk. Multi residue analysis was subsequently performed by HPLC diode array detection. Extraction yield by matrix solidphase dispersion using Nexus sorbent was higher than various investigated SPE protocols. Three analytical columns, two conventional silica based and one monolithic, were compared based on resolution, peak shape and retention time. The optimum method using Chromolith RP 18e (100 4.6 mm) achieved separation in less than 16 min. Method validation was performed according to the European Union Decision 2002/657/EC, determining linearity, selectivity, stability, decisi...
Different combinations of derivatisation and solid-phase microextraction followed by gas chromatography-mass spectrometry were optimised and evaluated for the analysis of phenoxy acid herbicides in water. The most successful derivatisation approach was aqueous-phase derivatisation with benzyl bromide. The benzyl esters were extracted most efficiently by the solid-phase microextraction fibre coated with polydimethylsiloxane-divinylbenzene. No carry-over problems were encountered with this fibre upon desorption at 250 degrees C. Detection limits in the ng/l range were obtained, while the relative standard deviations were between 14 and 42%.
A fast and highly sensitive electrospray ionization tandem mass spectrometry (ESI-MS/MS) method has been developed for the simultaneous determination of morphine, 6-methylacetylmorphine (6-MAM), codeine, cocaine and benzoylecgonine (BZE) in hair from drug abusers. Pulverized hair samples were subjected to an optimized matrix solidphase dispersion (MSPD) procedure with alumina, followed by diluted hydrochloric acid elution on column solid-phaseextraction (SPE) clean-up/pre-concentration. Alternatively, samples were also subjected to an optimized ultrasound assisted enzymatic hydrolysis (USEH) with Pronase E, followed by an off-line SPE clean up/pre-concentration procedure. Positive electrospray ionization and multiple reaction monitoring (MRM) with one precursor ion/product ion transition...
Novel sampling approaches have been investigated to improve the analytical utility of thermal desorption Direct Sampling Ion Trap Mass Spectrometry (DSITMS). Because DSITMS involves the direct introduction of samples into an ion trap mass spectrometer, problems with detection capabilities (sensitivity and selectivity) can often occur when performing trace analysis in complex matrices. Various sampling approaches have been evaluated to improve thermal desorption detection capabilities and to extend the utilities of DSITMS methodologies without significantly increasing analysis times or the cost-effectiveness of DSITMS methods. Three sampling approaches have been investigated including solidphase microextraction (SPME), solidphaseextraction columns (SPEC), and purge and trap.
In the present work, an analytical method for the simultaneous determination of seven non steroidal anti-inflammatory drugs (naproxen, ketoprofen, diclofenac, piroxicam, indomethacin, sulindac and diflunisal) and the anticonvulsant carbamazepine is reported. The method involves preconcentration and clean-up by solid-phase microextraction using polydimethylsiloxane/divinylbenzene fibers, followed by liquid chromatography with diode array detection analysis. Parameters that affect the efficiency of the solid-phase microextraction step such as soaking solvent, soaking period, desorption period, stirring rate, extraction time, sample pH, ionic strength, organic solvent and temperature were investigated using a Plackett-Burman screening design. Then, the factors presenting significant positive ...
Mixed zeolitic imidazolate framework 8 (ZIF-8) (nanometer and micron-sized) material were synthesized and applied as sorbent to sonication-assisted emulsification microextraction coupled to vortex-assisted porous membrane-protected micro-solid-phaseextraction (SAE-VA-m-SPE) of polycyclic aromatic hydrocarbons (PAHs) from water samples. Better extraction results was obtained by using the mixed sorbent for the extraction of PAHs from aqueous samples, than either nanometer or micron-sized ZIF-8 separately. The developed method proved to be a time-saving, highly efficient (total extraction procedure was less than 10min), accurate and robust method for water sample pretreatment. Parameters influencing the extraction efficiency such as desorption solvent, extraction solvent volume, emulsificati...
During July and August of 2006, 117 solid-phase samples were collected from abandoned uranium waste dumps, geologic background sites, and adjacent streambeds in the San Rafael Swell, in southeastern Utah. The objective of this sampling program was to assess the nonpoint source chemical loading potential to ephemeral and perennial watersheds from uranium waste dumps on Bureau of Land Management property. Uranium waste dump samples were collected using solid-phase sampling protocols. After collection, solid-phase samples were homogenized and extracted in the laboratory using a field leaching procedure. Filtered (0.45 micron) water samples were obtained from the field leaching procedure and were analyzed for Ag, As, Ba, Be, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, U, V, and Zn at the Inductively Coupled Plasma-Mass Spectrometry Metals Analysis Laboratory at the University of Utah, Salt Lake City, Utah and for Hg at the U.S. Geological Survey National Water Quality Laboratory, Denver, Colorado.\\r\
An initial review of research targeting applications of solidphase microextraction for organometallic speciation, published in 2001, encompassed literature from the early days of solidphase microextraction up to June 2000. In this article, the reader will find a compilation and discussion of relevant literature published from June 2000 to December 2004. Because of the maturity of the technique, only a brief overview of the measurement principles is presented. The major thrust of the article highlights applications of solidphase microextraction to the fields of elemental and organometallic analyses. In contrast to the earlier review, applications related to the determination of phosphorus-, sulfur-, bromine-, chlorine- and iodine-containing compounds have also been included for those cases where the target of the determination is the element or a specific molecule containing the element for which atomic spectroscopy has been advocated as a detection technique. Additionally, other microextraction techniques are also considered, including stirbar sorptive extraction and single droplet microextraction.
This paper summarizes studies on the application of fine powder materials to the biochemical engineering, as for the structural analysis of protein molecules on solidphase surface, and the development of functional fine particles and their application to bioproduct separation. The purpose of this series of investigations is to utilize existing fine powder materials by the new ideas, and to newly prepare fine powder materials suitable for the operation. Since ultra fine powder dispersion liquid is transparent and the light is not scattered, the structure of protein on the solidphase surface can be evaluated through the spectroscopic method, such as circular dichroic spectroscopy. By this method, the structural change of protein on the solidphase surface is illustrated. In addition, the magnetic separation method, coagulation separation method, and extraction separation method were investigated as fine powder separation method, and their effectiveness was revealed. Moreover, the affinity separation process of bioproducts using fine powders is introduced. 8 refs., 3 figs.
Recently, a solid-phase plant bioassay was developed to test sediment for contaminants that are potentially phytotoxic and may be bioaccumulated by plants (Folsom and Lee 1981a; Folsom, Lee, and Bates 1981). The solid-phase plant bioassay was shown to be an excellent tool for predicting whether or not contaminants (e.g., zinc and cadmium) were potentially bioaccumulated by the saltwater plant S. alterniflora. Folsom and Lee (1981a) pointed out, however, that the DTPA extraction data indicated that plant uptake from air-dried oxidized saltwater sediment would be substantially greater than from the same saltwater sediment under flooded reduced conditions. In addition, they suspected greater plant uptake once the excess salts were leached out and the sediments were dried. This technical note reports results of modifications to the original solid-phase plant bioassay to pursue this assumption.
A computationally designed polymer (CDP), based on the functional monomer ethylene glycol methacrylate phosphate (EGMP), with a reported high specific affinity for the neurotoxic paralytic shellfish poisoning (PSP) toxins saxitoxin (STX) and neosaxitoxin (neoSTX) was evaluated with a view to it being used in a solidphase adsorption toxin tracking (SPATT) system for deployment in the marine environment. In addition, a synthetic resin adsorbent (SEPABEADS? SP700) which had previously shown to adsorb lipophilic shellfish toxins (LSTs) from seawater was also assessed. Adsorption and desorption of the PSP toxin analogues on and from the CDP polymer and the SP700 resin were investigated. Both adsorbents were contained within dialysis membrane bags and deployed in PSP toxins-spiked seawater and ...
Three hybrid inorganic/organic adsorbents based on alumina and phenylazoformic acid 2-phenylhydrazide were synthesized, characterized and examined for their heavy metal sorption properties. The main purpose of this research paper is to study and explore the combined hybrid characters of inorganic/organic sorbents for the selective removal and preconcentration of heavy metals via static and dynamic solidphase techniques from industrial wastewater and drinking tap water samples as well. The hybrid inorganic/organic adsorbents were identified as strongly resistive to leaching in solutions with pH 1-7 and thermally stable up to 350°C. Optimization of heavy metal removal by implementation of newly designed hybrid inorganic/organic adsorbents was studied in presence of various factors as t...
A solid-phase adsorption method was developed to circumvent the disadvantage of the conventional liquid-phase PEGylation, i.e. the heterogeneity of the PEGylated products. The model proteins, human serum albumin (HSA) and staphylokinase (SAK), were adsorbed on the ion exchange chromatography media, followed by PEGylation with succinimidyl carbonate (SC)-mPEG5K and salt elution. Since PEGylation with SC-PEG5K alters the positive charge of the proteins, Q-Sepharose Big Beads and DEAE Sepharose Fast Flow were used for adsorption of HSA and SAK, respectively. Size exclusion chromatography and SDS-PAGE studies demonstrated that solid-phase PEGylation of proteins generate monoPEGylated proteins with the yield of 35?47%. Circular dichroism and intrinsic fluorescence studies showed that solid-phas...
A rapid and simple sampling approach using solidphase microextraction (SPME) for pyrethroid residues analysis in flue-cured tobacco was studied. The fibers coated with poly-dimethylsiloxane (PDMS) at 100 µm thickness were chosen. Extraction time of 180 s, desorption time of 120 s and desorption temperature of 280°C were selected. The whole sampling process, only including an ultrasonic assisted extraction step and a solidphase microextraction step, can be completed within 15 min. The associated SPME and ultrasonic assisted extraction using water as extracting solvent shows good results for tobacco pyrethroid residues determination. Results indicated that four pyrethroids can be determined simultaneously, and the limits of detection are below 35 ng g-1 using GC/MS in selected ion monitoring (SIM) mode. The reproducibility of the technique is found to be better than 11.8% RSD.
A new Molecularly Imprinted SolidPhaseExtraction (MISPE) protocol was developed for the selective extraction and purification of glycyrrhizic acid (GL) from liquorice roots. Non-covalent MIP were synthesized using methacrylic acid (MAA), 2-(dimethylamino)ethyl methacrilate (DMAEM) or 2-hydroxyethylmetacrylate (HEMA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent. After the evaluation of the selectivity of the GL imprinted polymers, the performance of these materials as SolidPhaseExtraction (SPE) sorbents was investigated. MIP having HEMA as functional monomer were found to be able to selectively extract almost 80% of GL content in liquorice roots. The proposed MISPE-HPLC procedure has good precision, thus it can be successfully used for the purif...
Introduction: The analysis of pediatric and adult hair is a useful non-invasive biomarker to effectively detect long term exposure to various xenobiotics, specifically drugs of abuse such as cocaine, opiates and amphetamines. Very often individuals are using, or are exposed to multiple drugs simultaneously and therefore it is important to be able to detect them in the same analysis. We have developed a sensitive and specific solidphase micro extraction (SPME) coupled with gas chromatography mass spectrometry (GC/MS) to detect 17 different analytes in hair using a single extraction method. Method: Five milligrams of hair is extracted overnight, subjected to solidphaseextraction (SPE) and then to SPME-GC/MS. The aimed analytes include amphetamine, methamphetamine, MDA, MDMA, cocaine, benz...
Abstract in english The pyrethroids bifenthrin, permethrin, cypermethrin and deltamethrin were extracted by solidphaseextraction (SPE) and solidphase microextraction (SPME). The analysis were performed on a gas chromatograph with electron capture detection (GC-ECD). Octadecil Silano-C18, Florisil and Silica stationary phases were studied for SPE. Better results were obtained for Florisil which gave recoveries from 80% to 108%. Pyrethroids extraction by SPME showed a linear response and a (more) detection limit of 10 pg ml-1. Although the data showed that the two extraction methods were able to isolate the pesticide residues from water samples, the best results were obtained by using SPME which is more sensitive, faster, cheeper, being a more useful technique for the analysis of pyrethroids in drinking water.
A rapid and simple preconcentration step applying packed-fiber solid-phaseextraction columns has been investigated to vitamin B12. The extraction performance of the new method was investigated preliminarily on vitamin functional drink. The analysis used a reversed-phase C18 column, with a photo-diode array detector at 220nm. The samples were preconcentrated with packed-fiber solid-phaseextraction columns. Good linearity was observed in vitamin functional drink. The repeatability of extraction performance, expressed as relative standard deviations, was from 3.5% to 4.3%. The limit of detection (LOD) is 5ngmL^-^1 (S/N=3). Finally, the method had been applied for the determination of vitamin B12 in vitamin functional drink.
Methods for the multiresidue extraction, cleanup and GC/MS determination of 142 pesticides and pesticide metabolites in soil have been developed. The use of solidphaseextraction cartridges makes it possible to clean up the soil sufficiently so that the equivalent of 40 mg. soil may be injected onto the GC capillary column without overloading or harming the column. Combining this clean-up method with chemical ionization ion trap detection allowed for very low limits of detection.
Recent advances in the use of solid-phase microextraction (SPME) in environmental analysis, including fiber coatings, derivatization techniques, and intube SPME, are reviewed in this article. Several calibration methods for SPME, including traditional calibration methods, the equilibrium extraction method, the exhaustive extraction method, and several diffusion-based calibration methods, are presented. Recent developed SPME devices for on-site sampling and several applications of SPME in environmental analysis are also introduced.
A method is described for the screening, quantification and confirmation of a variety of estronenic substances in animal tissues. A solid-phaseextraction technique combined with a liquid/liquid extraction allows for rapid sample preparation and high throughput for the following compounds in bovine liver, muscle and kidney: diethylstilbestrol, dienestrol, hexestrol, zeranol, taleranol, zearalanone, zearalenone, zearalenol, estradiol and estriol. Gas chromatography/mass spectrometry and selected ion monitoring is used for the determination with detection limits ranging from 50 to 150 ppt. PMID:3349206
A variety of analyses were conducted on selected sediment samples collected from two wells (299 W15-46 and 299-W15-48) drilled near the 216-Z-9 Trench to elucidate the form and potential for Pu and Am to be mobilized under present conditions and those that could be expected in future remediation scenarios. Analyses included moisture content, determination of the less than sand size fraction (silt plus clay), carbon analysis, SEM/EDS analysis, microwave-assisted acid digestions for total element analysis, and extraction tests using Hanford groundwater as the leachate. Results of the extraction tests were used as input to conduct equilibrium geochemical modeling of the solutions with Geochemist’s Workbench®. Geochemical modeling results for Pu were evaluated in terms of recent conclusions regarding the solubility and redox reactions of Pu by Neck et al. (2007a, 2007b). It was found that the highest concentrations of Pu and Am were associated with sediments of low silt/clay content and occur above silt/clay rich layers within the sediment profile. It was also found that the Pu and Am were relatively enriched in the silt/clay portion of these samples. The fact that the highest concentrations of Pu and Am occurred in sediments with low silt/clay contents suggests that waste solutions had perched on top of the low permeability silt/clay rich layers and interactions with the high silt/clay layers was minimal. SEM/EDS analysis indicated that the Pu and Am in these sediments does not occur as discrete micron size particles, and therefore must occur as mononuclear or polynuclear/ nanoclusters size particles adsorbed throughout the sediment samples. Leaching of these samples with Hanford groundwater indicates that release of Pu and Am from the sediments is correlated most significantly with the acidity of the water and not the initial concentrations of Pu and Am in the sediments. Only extracts that were acidic after contact with the sediments (pH 4.3 to 5.4) contained detectable concentrations of extractable Pu and Am. Water extracts from samples containing high concentrations of TBP suggest that if the TBP degradation products DBP and MBP are available in these sediments, they do not significantly increase the extractability of Pu or Am. Geochemical modeling results suggest that the concentrations of Am in water in contact with these sediments is not controlled by the solubility of Am(OH)3(c), but rather by desorption of Am that has been previously adsorbed to the sediments during the period of active wastewater disposal. Sediment extracts that had measureable concentrations of Am only occurred in samples that were fairly acidic (pH 4.3 to 4.6), indicating that Am will remain effectively sequestered to sediments when pH conditions approach those of normal Hanford groundwater (mildly alkaline, ~ pH 8). The geochemical modeling results indicate that Pu in acidic extracts is significantly undersaturated with respect to PuO2(am). However, recent reviews of Pu solubility and redox reactions suggest that the data used for these calculations is incomplete (Neck et al. 2007a, 2007b). The results of Neck et al. (2007a, 2007b) suggest that Pu concentrations in solutions in contact with the 216-Z-9 Trench sediment samples might be controlled by a mixed valent solidphase [(PuV)2x(PuIV)1-2xO2+x(am)] with various dissolved Pu(V) complexes and Pu(IV)O2(am) colloids or nanoclusters being the dominant species in solution for typical Hanford groundwater conditions. Adsorption is likely to have a major impact on the mobility of these species (Neck et al. 2007a, 2007b; Clark et al. 2006; Kaplan et al. 2006; Powell et al. 2005). Further research is planned to verify these hypotheses.
Abstract in english This review attempts to provide an updated overview of the Quick, Easy, Cheap, Effective, Ruged and Safe (QuEChERS) multiresidue extraction method, that involves initial extraction in acetonitrile, an extraction/partition step after the addition of salt, and a cleanup step utilizing dispersive solidphaseextraction. QuEChERS method is nowadays the most applied extraction method for the determination of pesticide residues in food samples, providing acceptable recoveries f (more) or acidic, neutral and basic pesticides. Several applications for various food matrices (fruits, vegetables, cereals and others) in combination with chromatographic mass spectrometry analysis were presented.
Polycyclic musk fragrances are widely used as ingredients in personal care products, shampoos, lotions, and household cleaning agents. These chemicals have relatively high octanol-water partition coefficients, and therefore tend to accumulate in sediments, sludge, and biological tissues. We analyzed shrimp and sediment samples for the presence of synthetic musks. Samples were extracted using accelerated solvent extraction. Gel permeation chromatography and solidphaseextraction with silica were used to clean the extracts. The extracts were analyzed with Gas Chromatography Mass Spectrometry with Electron Impact ionization (GC-MS-EI) in selected ion monitoring (SIM) mode. Sediment samples were collected from three tidal tributaries of the Chesapeake Bay. HHCB was detected in concentrations ...
A method to identify and quantify megastigmane norisoprenoid compounds in wines was developed using headspace solidphase micro extraction (SPME) coupled with gas-chromatography/mass-spectrometry (GC-MS). Three different compounds were quantified by stable isotope dilution assay (SIDA): b-damascenone, b-ionone and a-ionone. Particular attention was paid to maximising the method's sensitivity while reducing the extraction time. To optimise the extraction conditions, a statistically designed experiment was performed using extraction time, extraction temperature and ethanol content as operating variables. Five different SPME fibres suitable for the analysis of volatile compounds were compared. This study confirmed that the PDMS/DVB coating performs best for the quantification of b-damascenone...
A simple, rapid and reliable method was proposed for the simultaneous determination of 27 pesticides (organophosphorus, organochlorine, pyrethroid and carbamate pesticides) in Radix astragali. The pesticides were extracted by acetonitrile and the experimental variables, such as temperature, extraction time and volume of acetonitrile, were optimized through orthogonal array experimental design. Cleanup of extracts was performed with dispersive-solidphaseextraction using primary secondary amine (PSA) as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography–mass spectrometry in selected ion monitoring mode (GC–MS, SIM). The linearity of the calibration curves is good in matrix-matched standard, and yields the coefficients of...
H 218/54 is a potent inhibitor of human renin activity (pIC50 = 8.3 at pH 6) and is therefore a potential agent for blood pressure reduction. This lipophilic compound is highly bound to plasma proteins, e.g. 99.7% in rats and 99.6% in humans. For pharmacokinetic studies, a quantitative assay for 3H-H 218/54 in plasma has been developed. On top of an AASP phenyl solid-phase cartridge 70 microliters of rat plasma or 1 ml of cynomolgus plasma was mixed with 200 microliters of water containing 20% acetone. The acetone displaced the substance from plasma proteins without precipitation of the sample and clogging of the extraction column. The mixture was passed through the cartridge, which adsorbed 3H-H 218/54. The cartridge was placed in an AASP autosampler connected to a reversed-phase LC system, with a Vydac C-18 column and CH3CN-H2O-TFA (60:40:0.1, v/v/v) as mobile phase. The effluent from the separation column was collected in fractions for radioactivity counting. Recovery, as measured after adding various amounts of tritium-labelled H 218/54 to blank plasma followed by repeated analysis of the samples, was close to 100% with relative standard deviations between 1.4 and 3.0%. At the lowest level tested, 200 dpm per sample, the recovery was 120% with a relative standard deviation of only 10%. The sensitivity of the method will depend on the specific radioactivity of the dose given. PMID:1298403
A simple and robust method using solid-phaseextraction (SPE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of 14 drugs of abuse and their metabolites (cocainics, amphetamine-like compounds, cannabinoids, and opiates) in surface waters has been developed. Seven SPE adsorbents (Oasis HLB, Oasis MCX, Oasis Wax, Supelselect HLB, Strata-X, Strata-XCW), amount of sorbent bed, water volume, and pH were investigated. The highest recoveries, as well as the simplest protocol, were obtained for Oasis HLB cartridges (6 mL/200 mg) using 250 mL of water. The proposed method was linear in a concentration range from 0.03-6 to 300-60,000 ng/L depending on the compound, with correlation coefficients higher than 0.998. Matrix effects have been studied in surface water samples, and several isotope-labeled internal standards have been evaluated as a way to compensate the signal suppression observed. Limits of detection (LODs) and quantification (LOQs) ranged from 0.01 to 1.54 ng/L and from 0.03 to 5.13 ng/L, respectively. Recoveries were 71-102% at the LOQ level and 77-104 at 50 ng/L. The intra-day and intermediate precisions were from 1% to 8% and from 2% to 11%, respectively. The present work reports for the first time the occurrence of drugs of abuse residues in surface water samples from the Natural Park of L'Albufera (Valencia, Spain). Codeine, cocaine, benzoylecgonine, ecgonine methylester, amphetamine, 3,4-methylendioxy methamphetamine, morphine, and methadone were quantified with median values of 11.10, 0.02, 5.59, 0.08, 0.21, 0.75 and 0.14 ng/L respectively, and 11-nor-9-carboxy-Delta9-tetrahydrocannabinol was detected in one sample at levels
Swine operations can affect air quality by emissions of odor, volatile organic compounds (VOCs) and other gases, and particulate matter (PM). Particulate matter has been proposed to be an important pathway for carrying odor. However, little is known about the odor-VOCs-PM interactions. In this research, continuous PM sampling was conducted simultaneously with three collocated TEOM analyzers inside a 1000-head swine finish barn located in central Iowa. Each TEOM (tapered element oscillating microbalance) was fitted with total suspended particulate (TSP), PM-10, PM-2.5 and PM-1 preseparators. Used filters were stored in 40 mL vials and transported to the laboratory. VOCs adsorbed/absorbed to dust were allowed to equilibrate with vial headspace. Solid-phase microextraction (SPME) Carboxen/polydimethylsiloxane(PDMS) 85 ?m fibers were used to extract VOCs. Simultaneous chemical and olfactometry analyses of VOCs and odor associated with swine PM were completed using a gas chromatography-mass-olfactometry (GC-MS-O) system. Fifty VOCs categorized into nine chemical function groups were identified and confirmed with standards. Five of them are classified as hazardous air pollutants. VOCs were characterized with a wide range of molecular weight, boiling points, vapor pressures, water solubilities, odor detection thresholds, and atmospheric reactivities. All characteristic swine VOCs and odorants were present in PM and their abundance was proportional to PM size. However, the majority of VOCs and characteristic swine odorants were preferentially bound to smaller-size PM. The findings indicate that a significant fraction of swine odor can be carried by PM. Research of the effects of PM control on swine odor mitigation is warranted.
A novel method is described for the preparation of superparamagnetic mesoporous maghemite (?-Fe2O3)/silica (SiO2) composite microspheres to allow rapid magnetic separation of DNA from biological samples. With magnetite (Fe3O4) and silica nanoparticles as starting materials, such microspheres were synthesized by the following two consecutive steps: (1) formation of monodispersed organic/inorganic hybrid microspheres through urea-formaldedyde (UF) polymerization and (2) removal of the organic template and phase transformation of Fe3O4 to ?-Fe2O3 by calcination at elevated temperatures. The as-synthesized particles obtained by heating at temperature 300 °C feature spherical shape and uniform particle size (dparticle=1.72 ?m), high saturation magnetization (Ms=17.22 emu/g), superparamagnetism (Mr/Ms=0.023), high surface area (SBET=240 m2/g), and mesoporosity (dpore=6.62 nm). The composite microsphere consists of interlocked amorphous SiO2 nanoparticles, in which cubic ?-Fe2O3 nanocrystals are homogeneously dispersed and thermally stable against ?- to ?-phase transformation at temperatures up to 600 °C. With the exposed iron oxide nanoparticles coated with a thin layer of silica shell, the magnetic microspheres were used as a solid-phaseadsorbent for rapid extraction of genomic DNA from plant samples. The results show that the DNA templates isolated from pea and green pepper displayed single bands with molecular weights greater than 8 kb and A260/A280 values of 1.60-1.72. The PCR amplification of a fragment encoding the endogenous chloroplast ndhB gene confirmed that the DNA templates obtained were inhibitor-free and amenable to sensitive amplification-based DNA technologies.
This paper shows an analytical methodology based on solid-phaseextraction by XAD-2 adsorbent and gas chromatography (GC) coupled with nitrogen-phosphorus (NPD) and ion-trap mass spectrometry detectors (ITMS) in negative chemical ionization (NCI) mode analyses for investigating organophosphorus pesticides (OPs) at trace levels (in nanograms per cubic meter) in the atmosphere: in particular, we set up a procedure for analyzing 38 OPs. For the analytical methodology linearity responses have been obtained in GC-NPD (r > 0.9982) and GC-NCI/ITMS (r > 0.9974) in a large linearity range (0.10-500 pg ?L(-1) in both cases) whereas the limits of detection range between 0.01 and 0.03 pg ?L(-1) in both the techniques with a relative standard deviation (RSD) below 9.0 in both cases. Particular attention has been devoted to investigate the effect of different solvents (n-hexane, benzene, chloroform, carbon disulfide, acetonitrile) on the OP recovery as well the breakthrough volumes have been evaluated (100% recovery up to 4,286 L g(-1)). The study has also investigated the OP recoveries at different sampling flow rates (1.5 and 2.0 L min(-1)) for determining the optimal conditions for sample collection. Finally, the whole approach has been successfully applied to real samples collected in four different areas in the Molise region (Central Italy) during different seasons: the results show that parathion-ethyl, dimethoate, omethoate, and malathion are present in all periods at low levels (ranging between 70 and 10 ng m(-3)): their levels in such periods can be correlated with spraying as well atmospheric conditions favoring the dispersion/accumulation of these pollutants. PMID:22760505
The report is a summary of work performed by PNL on the extraction of semivolatile organic materials (SVOCs), for example, polynuclear aromatic compounds, from various adsorbents and environmental matrices, using supercritical fluids (SCFs) as extractants. The results of the work...
The report describes the development and evaluation of on-line supercritical fluid extraction-gas chromatography instrumentation and methodology for the analysis of volatile organic compounds (VOC) from adsorbent sampling devices. Supercritical fluid extraction offers potential a...
A novel method is described for the extraction of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxy-methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxyethylamphetamine, N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine, and 3,4-(methylenedioxyphenyl)-2-butanamine, from human whole blood using molecularly imprinted solid-phaseextraction as highly selective sample clean-up technique. Whole blood samples were diluted with 10 mmol/L ammonium acetate (pH 8.6) and applied to a SupelMIP-Amphetamine molecularly imprinted solid-phaseextraction cartridge. The cartridge was then washed to eliminate interferences, and the amphetamines of interest were eluted with formic acid/methanol (1:100, v/v). After derivatization with trifluoroacetic anhydride, the analytes were quantified using gas chromatography-mass spectrometry. Recoveries of the seven amphetamines spiked into whole blood were 89.1-102%. The limits of quantification for each compound in 200 ?L of whole blood were between 0.25 and 1.0 ng. The maximum intra- and inter-day coefficients of variation were 9.96 and 13.8%, respectively. The results show that methamphetamine, amphetamine, and methylenedioxyphenylalkyl-amine designer drugs can be efficiently extracted from crude biological samples such as whole blood by molecularly imprinted solid-phaseextraction with good reproducibility. This extraction method will be useful for the pretreatment of human samples before gas chromatography-mass spectrometry. PMID:22271670
We report the design, fabrication, and evaluation of a ?-preconcentrator chip that utilizes an array of solid-phase microextraction (SPME) needles coated with in-situ-grown carbon adsorbent film. The structure of the SPME needle (diameter=100?m, height=250?m) array inside the sampling chamber was fabricated using a deep reactive-ion etching (DRIE) process to enhance the attachable surface area for adsorbent film. Heaters and temperature sensors were fabricated onto the back of a ?-preconcentrator chip using lithography patterning and a metal lift-off process. The devices were sealed by anodic bonding and diced prior to the application of the adsorbent film. An adsorbent precursor, cellulose was dissolved in water and dynamically coated onto the SPME needle array. The coated cellulose film was converted into a porous carbon film via pyrolysis at 600°C in a N(2) atmosphere. The surface area of the carbon adsorbent film was 308m(2)/g, which is higher than that of a commercial adsorbent Carbopack X. A preconcentration factor as high as 13,637-fold was demonstrated using toluene. Eleven volatile organic compounds (VOCs) of different volatilities and functional groups were sampled and analyzed by GC-FID, and the desorption peak widths at half height were all less than 2.6s after elution from a 15m capillary GC column. There was no sign of performance degradation after continuous operation for 50 cycles in air. PMID:23158327
Effects of sediment disturbance, storage temperature (230 C and 40 C) and storage time on chemistry and toxicity of sediment and pore water were evaluated using two sediments (sandy freshwater and organic estuarine) contaminated with metals. Solid-phase (10 d with water renewal) and pore-water (96-h static) toxicity tests with Hyalella azteca were conducted upon collection and at two week intervals for 8--10 weeks. Chemistries (redox, pH, conductivity, alkalinity, ammonia, trace metals, major cations and anions) were measured at each toxicity testing interval. Following extraction, pore-water chemistry changed significantly during the initial 96 h due to oxidation reactions and CO{sub 2} equilibration. Pore water collected in situ was slightly less toxic and had major differences in water chemistry compared to pore water extracted from homogenized sediment. Storage temperature and time significantly influenced pore-water toxicity and chemistry, but had minimal effect on solid-phase toxicity. After four weeks, the highly-toxic sandy sediment became slightly less toxic in solid-phase tests and Significantly less toxic in pore-water tests, coinciding with changes in trace-metal concentrations, activities, and speciation. The estuarine sediment became slightly more toxic in both solid-phase and pore-water tests after four weeks, but returned to original levels after six and eight weeks. Sediment disturbance, storage temperature, and storage time significantly influenced toxicity and pore-water chemistry.
The possibility is established of isolating sulfurous compounds by adsorbents and the dependence of the isolation of sulfurous compounds on the radius of the pores of the adsorbent is determined and it is established that adsorbents with a pore radius of 20 to 28 angstroms must be selected for extracting sulfur organic compounds from benzine fractions. The adsorptive capability of certain adsorbents based on extraction of sulfurous compounds is identified. The desorptive capability of a number of organic solvents is studied during regeneration of a spent absorbent after purification of sulfurous benzine and it is established that the absorbent regeneration time is a strict function of the nature of the desorbent and the molecules absorbed on the surface (Pv) of the adsorbent. The order of saturation of the pores of the adsorbent by heteroorganic and hydrocarbon compounds relative to the size of their molecules and the radius of the pores of the adsorbent is determined.
Arsenic is a wide-spread toxin contaminating water from both natural (as in the case of South and Southeast Asia) and anthropogenic sources. Its high affinity for soil solids helps to regulate the deleterious impacts of this toxic element on ecosystem and human health. Iron (hydr)oxides are of particular importance in controlling dissolved concentrations of arsenic, making the behavior of these substrates crucial to understanding the transport and ultimate fate of arsenic. Ferrihydrite is one of the most active forms of Fe (hydr)oxides, and aluminum-substituted ferrihydrite is a common form of this phase in soils and sediment. Sorption of Fe(II) catalyzes the transformation of the thermodynamically unstable ferrihydrite to more thermodynamically stable Fe (hydr)oxides. Although the process of ferrihydrite transformation has been extensively studied, the role of structural aluminum and adsorbed arsenic on the Fe(II)-catalyzed transformation of ferrihydrite is unknown. Hence, the objective of this study was to compare how ferrihydrite and aluminum-substituted ferrihydrite differ in their retention of Fe(II) and the resulting transformation rates and products in the presence and absence of arsenic. Sand coated with ferrihydrite and aluminum-ferrihydrite (with and without adsorbed arsenic) was packed into columns and flow of circumneutral groundwater solution containing 0.2 to 4 mM Fe(II) was initiated. Breakthrough of Fe(II) was monitored using the ferrozine colorimetric assay to determine Fe(II) retention in the solidphase. The solidphase was characterized using Fe K-edge X-ray absorption spectroscopy and scanning electron microscopy. Structural aluminum limits Fe(II) sorption, and, as a consequence, the extent of the aluminum-substituted ferrihydrite transformation is much less than that of ferrihydrite. Adsorbed As further decreases Fe(II) retention on aluminum-ferrihydrite. In contrast, Fe(II) retention on ferrihydrite is enhanced in the presence of arsenic due to the promoted formation of magnetite, at the expense of goethite, resulting in greater Fe(II) incorporation in the solidphase.
This study describes the development of a method suitable for the analysis of nineteen major urinary steroid metabolites in human urine. The analytes of interest were isolated from urine using solidphaseextraction, subjected to enzymatic hydrolysis and again extracted applying solidphaseextraction. After derivatization, methyloxime-trimethylsilyl ether derivatives of steroid hormones were identified by gas chromatography-mass spectrometry (GC/MS) and quantified by gas chromatography with flame ionization detector (GC/FID). The quantification method was validated for linearity, trueness, precision and selectivity. The limits of detection were between 6.2 and 7.2ng/mL and limits of quantification were between 12.3 and 14.8ng/mL. The established method was applied to analyze 28 urine samp...
This paper deals with comparison of efficiency of extraction techniques (solid-phaseextraction, SPE and solid-phase microextraction, SPME) used for extraction of nitrate esters (ethyleneglycoldinitrate, EGDN and nitroglycerin, NG), representing the first step of the method of quantitative determination of trace concentrations of nitrate esters in water samples. EGDN and NG are subsequently determined by means of high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Optimization of SPE and SPME conditions was carried out using model water samples. Seven SPE cartridges were tested and the conditions were optimized (type of sorbent, type and volume of solvent to be used as eluent). For both nitrate esters the limit of detection (LOD) and the limit of quantification (LO...
The tobacco-specific nitrosamine metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a valuable biomarker for human exposure to the carcinogenic nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in tobacco and tobacco smoke. In this work, an efficient and sensitive method for the analysis of NNAL in human hair was developed and validated. The hair sample was extracted by NaOH solution digestion, purified by C18 solid-phaseextraction (SPE) and molecularly imprinted solid-phaseextraction, further enriched by reverse-phase ultrasound-assisted dispersive liquid?liquid microextraction (USA-DLLME) into 1.0?% aqueous formic acid, and finally analyzed by liquid chromatography?electrospray ionization tandem mass spectrometry. Good linearity was obtained in the range ...
A solvent free solid-phase microextraction (SPME) method has been developed to determine methyl mercury and Hg(II) in sediment, seawater and biota samples from TTC area (Mumbai, India) using gas chromatograph-mass spectrometer (GC-MS). The analytical method consists of phenylation with Na[B(C{sub 6}H{sub 5}){sub 4}], simultaneous solid-phase microextraction of the derivatives, followed by a final GC-MS analysis. Experimental design methodology was used for optimization of important process parameter, like SPME fiber coating (nature and thickness), extraction time, extraction temperature, and pH. After extraction, the fiber is directly injected to the injector port of GC for desorption, separation and quantification. The absolute detection limits obtained for methylmercury and inorganic mercury were 0.02 and 0.05 ng as Hg, respectively. Standard reference materials were analyzed for validation of the methodology. The total mercury content in different matrices was determined using hydride generation atomic adsorption spectrometry (HG-AAS)
Sampling time, volume of water, volume of head-space, temperature, addition of salts and agitation of polychlorinated biphenyls (PCBs) in water samples were studied under non-equilibrium conditions. The possibility of sampling the head space (head-space solidphase microextraction, or HSSPME) instead of immersing the fiber into water (solidphase microextraction, or SPME) was also investigated. In spite of the low partitioning of PCB into the head-space, HSSPME provided higher sensitivity than SPME at both room temperature, and also at 100 degree C. The method has been applied to a water sample from an industrial harbour and compared to liquid-liquid extraction with very similar results. The HSSPME method was judged to be particularly useful in emergencies work because it is much faster, and is a convenient alternative to liquid-liquid extraction. It also has the benefit of working with a much smaller sample size since it combines sampling and extraction/concentration in one single step. 12 refs., 8 figs.
Analyte enrichments in US Environmental Protection Agency (EPA) methods for environmental pollutants are generally performed using sample preparation techniques such as liquid-liquid extraction, liquid-solid extraction and purge & trap dynamic headspace concentration. The recent development of SolidPhase Microextraction (SPME) has provided another alternative which efficiently extracts organic analytes present in air or aqueous samples. We have successfully developed a unique sample preparation method which combines the power/advantages of SolidPhase Microextraction and standard EPA methodology. Subsequent analysis results in successful detection of ultratrace organic compounds with excellent sensitivity. EPA 525, 625, 8270 semivolatile organic compound have been successfully determined using Gas Chromatography/ Mass Spectrometry (GC/MC) at sub-parts per billion (ppb) levels. EPA 608, 8080 halogenated pesticides have also been readily detected with Electron Capture Detector (ECD) at parts per quadrillion (ppq) levels.
A new microextraction technique based on ionic liquid solid-phase microextraction (IL-SPME) was developed for determination of trace chlorophenols (CPs) in landfill leachate. The synthesized ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]), was coated onto the spent fiber of SPME for extraction of trace CPs. After extraction, the absorbed analytes were desorbed and quantified using gas chromatography-mass spectrometry (GC/MS). The term of the proposed method is as ionic liquid-coated of solid-phase microextraction combined with gas chromatography-mass spectrometry (IL-SPME-GC/MS). No carryover effect was found, and every laboratory-made ionic liquids-coated-fiber could be used for extraction at least eighty times without degradation of efficiency. The chlorophen...
Solidphaseextraction (SPE) and dispersive solid-phaseextraction (d-SPE) were compared and evaluated for the determination of l-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with an electron capture detector (GC-ECD). Several SPE sorbents such as graphitised carbon black (GCB), primary secondary amine (PSA), C18, silica, and florisil were tested in order to minimise fat residues. The results show that mixed sorbents using GCB and PSA obtained cleaner extracts than a single GCB and PSA sorbents. The average recoveries obtained for each pesticide ranged between 81% and 114% at five fortification levels with the relative standard deviation of less than 7% in all cases. The limits of detection for these pesticides were ranged between 0.025 and 0.05mg/g. The proposed...
A sorbent based on the aptamer for ochratoxin A was immobilized onto magnetic nanospheres (MNS) and used to develop a magnetic solid-phaseextraction procedure to clean up food samples in conjunction with high-performance liquid chromatography separation and fluorescence detection. Specific retention of ochratoxin A by the sorbent was demonstrated, and the capacity of the MNS-aptamer sorbent was determined. The efficacy of this new approach was successfully evaluated through comparison with solid-phaseextraction on commercial C18 cartridge. Several different food samples fortified in the range of with 2.5-50mg/kg yielded mean recoveries from 67% to 90%, respectively. Finally, this oligosorbent was applied to the selective extraction of ochratoxin A from unfortified food samples.
A new solid-phaseextraction sorbent, octadecyl modified magnesium oxide (C18-MgO) microspheres, was successfully prepared in the present work. Its composition, morphology and structure were studied by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2 adsorption-desorption technique, and solid-state nuclear magnetic resonance (NMR). The as-synthesized C18-MgO was employed as a solid-phaseextraction sorbent for the enrichment of polycyclic aromatic hydrocarbons (PAHs) in aqueous solutions. Several factors affecting the extraction efficiency of PAHs, including the type and concentration of organic modifiers, flow rate, sample volume, and the types of rinsing solvents and eluting solvents, were investigated systematically. The results demonstrated that C1...
Identification of putative biomarker molecules within the genus Corydalis (Papaveraceae) was pursued by combining conventional off-line sample enrichment with high-performance liquid chromatography-solidphaseextraction-nuclear magnetic resonance (HPLC-SPE-NMR) based structure elucidation. Off-line reversed phase solidphaseextraction (SPE) was used to enrich the desired analytes from a methanolic extract (93mg dry weight) of a miniscule single tuber (233mg dry weight) of C. solida. An aliquot of the SPE fraction (2.1mg) was subjected to separation in the HPLC-SPE-NMR hyphenation. Chromatographic peaks bearing the metabolites under investigation were trapped in the SPE device in a single experiment and transferred to a 600MHz NMR spectrometer equipped with a 30ml cryofit insert fed into ...
We have developed a solid-phaseextraction method based on conductive polypyrrole (PPy) hollow fibers which were fabricated by electrospinning and in situ polymerization. The electrospun poly (e-caprolactone) (PCL) fibers were employed as templates for the in situ surface polymerization of PPy under mechanical stirring or ultrasonication to obtain burr-shaped or smooth fiber shells, respectively. Hollow PPy fibers, achieved by removing the PCL templates, were the ideal sorbents for solidphaseextraction of polar compounds due to their inherent multi-functionalities. By using the hollow PPy fibers, two important neuroendocrine markers of behavioural disorders, 5-hydroxyindole-3-acetic acid and homovanillic acid, were successfully extracted. Under the optimized conditions, the absolute recoveries of the above two neuroendocrine markers were 90.7% and 92.4%, respectively, in human plasma. Due to its simplicity, selectivity and sensitivity, the method may be applied to quantitatively analyse the concentrations of polar species in complex matrix samples. PMID:22398754
In this review, the preparation of a novel porous sheet designed for solid-phaseextraction (SPE) and a comparison of the preconcentration performance of metal ions with conventional sorbents are described. A porous sheet (MAPS) with an average pore diameter, porosity, and a thickness of 1.0 ?m, 75%, and 2 mm, respectively, was modified into an sorbent used for solid-phaseextraction, by radiation-induced graft polymerization. Ion-exchange and chelating groups were immobilized onto polymer chains grafted to the MAPS. Also, extractants were impregnated via a hydrophobic interaction with long alkyl chains introduced into the grafted polymer chains of the MAPS. The applicability of the resultant modified MAPSs was demonstrated by adopting them to analyses of real samples.
The tobacco-specific nitrosamine metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a valuable biomarker for human exposure to the carcinogenic nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in tobacco and tobacco smoke. In this work, an efficient and sensitive method for the analysis of NNAL in human hair was developed and validated. The hair sample was extracted by NaOH solution digestion, purified by C18 solid-phaseextraction (SPE) and molecularly imprinted solid-phaseextraction, further enriched by reverse-phase ultrasound-assisted dispersive liquid?liquid microextraction (USA-DLLME) into 1.0 % aqueous formic acid, and finally analyzed by liquid chromatography?electrospray ionization tandem mass spectrometry. Good linearity was obtained in the range ...
A method for the ultra trace analysis of 21 fluorobenzoic acids (FBAs) via GC-MS based on solid-phaseextraction (SPE) and derivatization with BF3.MeOH is described. All fluorobenzoic acids were enriched and determined simultaneously. Solid-phaseextraction on hydrophilic-lipophilic-balanced reversed-phase cartridges containing a poly(divinylbenzene-co-N-vinylpyrrolidone) polymer allowed a 250-fold enrichment of the acids if 100mL sample volume is used with extraction efficiencies between 71% and 94%. The method enables the determination of fluorobenzoic acid methyl esters (FBAMEs) down to the range of 6-44ngL^-^1 combined with a fast and easy sample-preparation (pH-adjusting prior to SPE and derivatization within 24h at 64^oC directly in the vial). It uses low amounts of chemicals and is ...
This study describes the synthesis of novel molecularly imprinted polymers based on multi-walled carbon nanotubes (MWNTs@MIPs) using oleanolic acid as the template, 4-vinylpyridine as the functional monomer and divinylbenzene as the cross-linker by heat-induced polymerization. The MWNTs@MIPs were characterized with Fourier transform infrared (FT-IR) spectrometry and scanning electron microscopy (SEM). The adsorption process of the MWNTs@MIPs towards oleanolic acid was investigated in detail. The properties of MWNTs@MIPs for solid-phaseextraction (SPE) were also evaluated. The results demonstrated the good imprinting effect and the comparable selectivity of MWNTs@MIPs. The optimized molecularly imprinted solid-phaseextraction (MISPE) procedure was applied to extract oleanolic acid from th...
This report described a method for simultaneous determination of cyanuric acid (CYA) and melamine (MEL) in dairy products. The samples were extracted by a mixture of acetonitrile/water and cleaned by graphite carbon/strong cation exchange (CARB/SCX) mixed-mode solidphaseextraction column. The CYA and MEL were derivatized with bis(trimethylsily1)trifluoroacetamide (BSTFA) containing 1% Trimethylchlorosilane (TMCS), and quantified with the internal standards of ^1^5N"3-cyanuric acid and ^1^3C"3-melamine by GC-MS. The results indicated that CARB/SCX mixed solidphaseextraction column could be used for sample pretreatment. The fortification recoveries were 80.8-101.5%, and the relative standard deviations (RSDs) were 3.6-7.9%. The detection limits of CYA and MEL were 0.025mgkg^-^1 and 0.01m...
BACKGROUND: Ethyl formate formulations are being considered to replace methyl bromide for fast grain disinfestation. Grain adsorbs ethyl formate rapidly, which can result in inadequate fumigation concentrations and unacceptable grain residues. A model of ethyl formate sorption kinetics will enable fumigation approaches to be determined that meet disinfestation and food safety requirements. RESULTS: This paper identifies all mass transport processes involved in ethyl formate sorption by wheat from published and experimental evidence. The model accounts for reaction losses of ethyl formate in air and grain using first-order kinetics, transport in the gas and solidphases with linear mass transfer coefficients and uses a linear partition relationship representation of sorption equilibrium. Ba...
A new process for the extraction of uranium from seawater was developed. In the process, uranium adsorption is effected using powdered magnetic adsorbents; the adsorbents are then separated from seawater using magnetic separation technology. This process is superior to a column method using a granulated hydrous titanium oxide adsorber bed in the following ways: (1) a higher rate of adsorption is realized because smaller particles are used in the uranium adsorption; and (2) blocking, which is inevitable in an adsorber bed, is eliminated. The composite hydrous titanium-iron oxide as a magnetic adsorbent having high uranium adsorption capacity and magnetization can be prepared by adding urea to a mixed solution of titanium sulfate and ferrous sulfate. Adsorption and desoprtion of uranium and the removal of the adsorbent using a small-scale uranium extraction plant (about 15 m/sup 3//d) is reported, and the feasibility of uranium extraction from seawater by this process is demonstrated. 10 figures.
Pisum sativum is of great economic and nutritional interest due to its protein content. Nevertheless, pea products are underused as a protein source in human food because of their strong beany flavour. Therefore, the objective of this study was to select an efficient and representative method to extract volatile molecules of pea flour. In the first step, three extraction methods were chosen: solidphase micro extraction (SPME); Purge and Trap extraction and solvent assisted flavour evaporation (SAFE). The corresponding extracts were analysed by gas chromatography coupled with mass spectrometry. In the second step, the sensory representativity of the extracts was assessed either by direct gas chromatography-olfactometry for SPME and for Purge and Trap extracts, or by sniffing for the aqueous SAFE extract. It appeared that SAFE extraction was the most suitable method because of its good extraction capacities and its high sensory representativity of the global odour of pea flour. PMID:22953805
A solid-phase microextraction (SPME) procedure followed by gas chromatography electron capture detection (GC/ECD) for the determination of triazole residues was developed. An experimental design with two steps was done. Firstly, a 26?2 fractional factorial design for screening several experimental variables (fiber-coating type, extraction temperature, extraction time, stirring rate, desorption temperature, and desorption time) was done. After, a two-factor central composite design for optimizing, the experimental conditions were carried out. The chosen experimental conditions were: fiber, PDMS/DVB; extraction time, 45?min; extraction temperature, 60??C; desorption time, 3?min; desorption temperature, 260??C, and stirring speed, 500?rpm. Using those conditions the limits of detection obtain...
A solid-phase microextraction (SPME) procedure followed by gas chromatography electron capture detection (GC/ECD) for the determination of triazole residues was developed. An experimental design with two steps was done. Firstly, a 26?2 fractional factorial design for screening several experimental variables (fiber-coating type, extraction temperature, extraction time, stirring rate, desorption temperature, and desorption time) was done. After, a two-factor central composite design for optimizing, the experimental conditions were carried out. The chosen experimental conditions were: fiber, PDMS/DVB; extraction time, 45 min; extraction temperature, 60 °C; desorption time, 3 min; desorption temperature, 260 °C, and stirring speed, 500 rpm. Using those conditions the limits of detection obtain...
A new simple and reliable method combining an acetonitrile partitioning extractive procedure followed by dispersive solid-phase cleanup (QuEChERS) with dispersive liquid?liquid microextraction (DLLME) and further gas chromatography mass spectrometry analysis was developed for the simultaneous determination of bisphenol A (BPA) and bisphenol B (BPB) in canned seafood samples. Besides the great enrichment factor provided, the final DLLME extractive step was designed in order to allow the simultaneous acetylation of the compounds required for their gas chromatographic analysis. Tetrachloroethylene was used as extractive solvent, while the acetonitrile extract obtained from QuEChERS was used as dispersive solvent, and anhydride acetic as derivatizing reagent. The main factors influencing QuECh...
Nitrosamines which have been detected in various latex products are carcinogens. The method for determination of volatile nitrosamines in latex products was developed using a combination of headspace solidphase micro-extraction (HS-SPME) and gas chromatography?mass spectrometry (GC?MS). A carboxen/polydimethylsiloxane (CAR/PDMS) fiber was used for HS-SPME involving the following variables: (1) agitation conditions, (2) extraction temperature (3) extraction time, and (4) salt concentration. The instrument performances of three detection systems including GC combined thermal energy analyzer, nitrogen chemiluminescence detector and MS were evaluated. The agitation conditions including magnetic stirring and ultrasonication were investigated by the comparison of extraction efficiency of HS-SPM...
A comprehensive method for the analysis of 11 target pharmaceuticals representing multiple commonly used therapeutic classes was developed for biological tissues (fish), reclaimed water, and the surface water directly affected by irrigation with reclaimed water. One gram of fish tissue homogenate was extracted by accelerated solvent extraction with methylene chloride followed by mixed-mode cation exchange solidphaseextraction (SPE) cleanup and analyzed by liquid chromatography-tandem mass spectrometry. Compared to previously reported methods, the protocol produces cleaner extracts resulting in lower method detection limits. Similarly, an SPE method based on Oasis HLB cartridges was used to concentrate and cleanup reclaimed and surface water samples. Among the 11 target compounds analyzed...
A method to determine ?-, ?- and ?-hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) in water and sediments was presented using solidphaseextraction (SPE) and/or solvent extraction. Recoveries from sediments were approximately 100% for all the chemicals, while recoveries of ?-, ?- and ?-HBCDs from water were dependent on the extraction method. In the case of dichloromethane (CH2Cl2) extraction, recoveries of ?-, ?- and ?-HBCD from landfill leachates were 77%, 88% and 92%, respectively. Technical difficulties in HBCD measurement are discussed in terms of the physico-chemical properties of HBCD isomers. The method was applied to landfill samples and marine sediment.
A fast and flexible multi-residue procedure for effective extraction of benzimidazole fungicides and the related transformation products in various raw agricultural commodities is developed for direct and simultaneous analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The new sample preparation method, introduced to allow direct extraction of the labile fungicides as the intact forms in complex matrices, is achieved using a conservative homogenizing extraction and multifunction adsorption cleanup (CHEMAC), which basically involves salting-out partitioning/extraction with acetate-buffered acetonitrile at low-temperature and sequential rapid solid-phase dispersive cleanup with a ternary sorbent mixture. The CHEMAC procedure was optimized and further modified by incorporat...
A simple, efficient and environmentally friendly method for the extraction and determination of five triazine herbicides in water and milk samples was developed by simultaneous liquid?liquid microextraction and carbon nanotube reinforced hollow fiber microporous membrane solid-phase microextraction coupled with high-performance liquid chromatography?diode array detection. The parameters that affect the extraction efficiencies, including the type and concentration of multi-walled carbon nanotube, type of membrane solvent and desorption solvent, the type and volume of the extraction solvent in sample solution, extraction time and temperature, the pH of sample solution, stirring rate, and ionic strength were investigated and optimized. Under the optimum conditions, the method shows a good lin...
During May, June, and July 2007, 58 solid-phase samples were collected from abandoned uranium mine waste dumps, background sites, and adjacent streambeds in Red, White, and Fry Canyons in southeastern Utah. The objectives of this sampling program were to (1) assess the nonpoint-source chemical loading potential to ephemeral and perennial drainage basins from uranium waste dumps and (2) assess potential effects on human health due to recreational activities on and around uranium waste dumps on Bureau of Land Management property. Uranium waste-dump samples were collected using solid-phase sampling protocols. After collection, solid-phase samples were homogenized and extracted in the laboratory using a leaching procedure. Filtered (0.45 micron) water samples were obtained from the field leaching procedure and were analyzed for major and trace elements at the Inductively Coupled Plasma-Mass Spectrometry Metals Analysis Laboratory at the University of Utah. A subset of the solid-phase samples also were digested with strong acids and analyzed for major ions and trace elements at the U.S. Geological Survey Geologic Division Laboratory in Denver, Colorado. For the initial ranking of chemical loading potential for uranium waste dumps, results of leachate analyses were compared with existing aquatic-life and drinking-water-quality standards. To assess potential effects on human health, solid-phase digestion values for uranium were compared to soil screening levels (SSL) computed using the computer model RESRAD 6.5 for a probable concentration of radium. One or more chemical constituents exceeded aquatic life and drinking-water-quality standards in approximately 64 percent (29/45) of the leachate samples extracted from uranium waste dumps. Most of the uranium waste dump sites with elevated trace-element concentrations in leachates were located in Red Canyon. Approximately 69 percent (31/45) of the strong acid digestible soil concentration values were greater than a calculated SSL. Uranium waste dump sites with elevated leachate and total digestible concentrations may need to be further investigated to determine the most appropriate remediation method.
The largest subject for putting the extraction of uranium from seawater in practical use is the development of high performance adsorbents for uranium. In this paper, the way of thinking about the development of adsorbents for extracting uranium from seawater and the recent reports on this subject are described. Next, the research on the adsorbing capacity and adsorbing rate of the adsorbents developed so far is summarized, and the way of thinking about the evaluation of adsorbent performance which is the base of the design of a system for extracting uranium from seawater is explained, taking amidoxime type adsorbent as the example. For Japan where energy resources are scant, the uranium contained in seawater, which is estimated to be about 4.2 billion t, is the most luring important element. Uranium is contained in seawater is very low concentration of 3 ppb, and exists as anion complex salt. In 1960s, the Harwell Atomic Energy Research Establishment in UK found out that titanium oxide hydrate is the most promising as the adsorbent. Also a number of organic absorbents have been developed. In order to bring adsorbents in contact with seawater, pumping, ocean current and wave force are utilized. Adsorbents are in spherical, fiber and film forms, and held as fixed beds and fluidized beds. (Kako, I.) 48 refs.
This study compared four extraction methods for the simultaneous determination of tetracyclines, macrolides, quinolones, sulphonamides and anthelmintics (including benzimidazoles and avermectins) in eggs by ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Solvent extraction, solid-phaseextraction (SPE), matrix solid-phase dispersion (MSPD) and modified QuEChERS procedure were compared in terms of recovery and number of veterinary drugs extracted. The solvent extraction procedure with a clean-up step provided better results than the other tested procedures. The QuEChERS procedure was simpler and faster, but extracted fewer compounds than solvent extraction. MSPD did not extract tetracyclines and quinolones, whereas macrolides and tetracyclines were not extracted when SPE was applied. The solvent extraction procedure was validated, obtaining recoveries ranging from 60% (sulfaquinoxaline) to 119% (levamisole) with repeatability values (expressed as relative standard deviations, RSDs) lower than 20% at two concentration levels (10 and 100 microg kg(-1)), except for erythromycin, emamectin and ivermectin that showed RSD values close to 25% at 10 microg kg(-1). Limits of quantification (LOQs) were always equal or lower than 5 microg kg(-1). Finally the method was applied to egg samples, and erythromycin, enrofloxacin, difloxacin, thiabendazole, emamectin and fenbendazole were detected in four samples. PMID:20113729
An extraction method consisting of both microwave-assisted extraction (MAE) and solidphaseextraction (SPE) was developed to extract pesticides of different polarities in infant milk formula. An experimental central face composite design was established to evaluate the effects of several MAE variables simultaneously such as temperature and pH of extractant. With Derringer desirability function, all pesticides were optimally extracted at 102degreeC within 20min with 4.56mL of extractant consisting of 0.1% of water in methanol at pH 12. Extraction efficiency was subsequently analysed with LC-MS/MS. The extraction recoveries ranging from 72% to 111% were obtained for all pesticides at fortification level of 5-100mgkg-1 with relative standard deviations (RSDs) of less than 8%. Compared with S...
The potential of microwave-assisted liquid-liquid and solidphaseextraction coupled with fluorescence spectroscopy and employing one- to three-way spectral data was assessed in terms of their capacity for the rapid detection of heavy polycyclic aromatic hydrocarbons (PAHs) in olive and sunflower oils. Tocopherols and pigments groups (chlorophyll and pheophytin) present in oil matrices were the main interference compounds in the detection of PAHs using fluorescence spectroscopy. Partial spectral overlap and inner-filter effects were observed in the emission range of the analytes. The effectiveness of removing these interferences using solidphaseextraction (silica, C18 and graphitized carbon black) was examined. Solidphaseextraction with silica was the most effective method for the removal of pigments and tocopherol and allowed for the detection of PAHs in edible oils using fluorescence spectroscopy. The limit of detection was observed to depend on the use of one-, two- or three-way fluorescence spectral data in the range of 0.8 to 7.0?gkg(-1). The individual recoveries of PAHs following the microwave-assisted L-L extraction and SPE with silica were assessed using HPLC-FD with satisfactory results. PMID:23141362
A rapid and reliable solid-phaseextraction method for HPLC analysis of opium alkaloids from Papaver plants was established. Fifty mg of dried and powdered plant sample was extracted with 5 ml of 5% acetic acid for 30 min under sonication. After centrifugation, 3 ml of the supernatant was loaded on a reversed-phase cation-exchange solid-phaseextraction cartridge. After seriate washings with 0.1 M hydrochloric acid and methanol, alkaloids were eluted with a mixture of 28% ammonia and methanol (1:19). The eluate was concentrated under nitrogen stream at 40 degrees C and the residue was dissolved in 50% aqueous methanol for high performance liquid chromatographic analysis. With this solid-phaseextraction method, the recovery of morphine, codeine, oripavine, thebaine, papaverine, noscapine and sanguinarine was from 99.94 to 112.18% when the standard alkaloids were added to the plant samples. Opium alkaloids of a variety of genus Papaver plants cultivated in a field and phytotron were analyzed by this method. PMID:16272729
This paper describes a new method for the determination of citalopram in biological fluids using molecularly imprinted solid-phaseextraction as the sample cleanup technique combined with high performance liquid chromatography. The molecularly imprinted polymers were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker, chloroform as porogen and citalopram hydrobromide as the template molecule. The novel imprinted polymer was used as a solid-phaseextraction sorbent for the extraction of citalopram from human serum and urine. Effective parameters on citalopram retention were studied. The optimal conditions for molecularly imprinted solid-phaseextraction consisted of conditioning with 1 mL methanol and 1 mL of deionized water at neutral pH, loading of citalopram sample (50 ?g L(-1)) at pH 9.0, washing using 1 mL acetone and elution with 3 × 1 mL of 10 % (v/v) acetic acid in methanol. The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of citalopram. Results from the HPLC analyses showed that the calibration curve of citalopram using MIP from human serum and urine is linear in the ranges of 1-100 and 2-120 ?g L(-1) with good precisions (2.5 and 1.5 % for 10.0 ?g L(-1)), and recoveries (between 82-86 and 83-85 %), respectively. PMID:22484836
A growth factor delivery system was developed that is based on the use of silyl-heparin, a chemically modified analogue of heparin. The silyl-heparin was adsorbed onto surfaces by hydrophobic interaction via the prosthetic unit and can then be used as a solid-phaseadsorbent for bFGF. All the coating steps were performed by adsorption, a process that allowed preparation of surfaces by immersion or "dip-coating". In this study a series of silyl-heparins were synthesized and each of the analogues found to function similar to unmodified heparin relative to their binding of antithrombin III and also the binding of bFGF. The silyl-heparins were found to be adsorbed onto a wide variety of substrates including polystyrene and lactide:glycolide copolymer. Enzyme-linked immumosorbant assay (ELISA) was used to establish that bFGF was readily bound to surface adsorbed silyl-heparin, and that the amount bound was directly related to amount offered for binding. Once adsorbed the silyl-heparin/FGF was able to induce capillary tube formation of endothelial cells and to increase the growth of endothelial cells. When coated onto suture material and implanted in muscle, the FGF/silyl-heparin coating caused an increased density of mesenchymal cells in the area of the implant. This coating method could prove to be useful in a number of tissue engineering applications for the local delivery of FGF and other growth factors. PMID:12236772
Experimental studies were designed to identify the active agents in Fe(II)-based degradative solidification/stabilization (Fe(II)-DS/S) that are responsible for the degradation of tetrachloroethylene (PCE) as well as the conditions that enhance the formation of these active agents. First, the conditions that lead to maximizing production of the active agents were identified by measuring the ability of various chemical mixtures to degrade PCE. Results showed that Fe(II), Fe(III), and Cl were the elements most closely associated with high degradation rates. In addition to elemental composition, unknown factors associated with the formation of solidphases could also be important in determining the extent of formation of active reducing agents. Second, instrumental analysis techniques (XRD, SEM, SEM-EDS) were used to identify compounds in chemical mixtures that were observed to have high activities for PCE degradation. SEM-EDS analysis indicated that Fe was associated with hexagonal particles, which is the typical shape of several AFm phases in hydrated Portland cement that are composed of calcium, aluminum/iron, hydroxide, and possibly other anions. No Fe-containing solidphases could be identified. Therefore, it appears that AFm phases are the most likely active agents for PCE degradation in mixtures containing Portland cement or its acid extract. Mixtures without cement did not form the same solidphases but were observed to form ferrous hydroxide as a major solidphase. PMID:17874793
A method is described for recovering bitumen from a carbonaceous solid containing extractable bitumen and for removing solid fines from the recovered bitumen consisting of: (a) contacting the carbonaceous solid with a solvent to dissolve at least 75 weight % of the bitumen in the carbonaceous solid in the solvent and to leave undissolved 1 to 25 weight % of the bitumen, and thereby to form a lower solidphase of coarse solids and an upper suspension of undissolved bitumen and fine solids in a solvent-dissolved bitumen liquid phase; (b) separating the upper suspension from the lower solidphase of coarse solids; (c) permitting at least a portion of the suspended undissolved bitumen to settle, with at least a portion of the suspended fines agglomerating and settling with the undissolved bitumen to form a second lower solidphase; (d) separating the upper solvent dissolved bitumen liquid phase from the second lower solidphase; and (e) separating the solvent and the bitumen fractions of the solvent-dissolved bitumen phase.
Trace quantities of airborne herbicide residues were collected on adsorbent bed cartridges and were subsequently extracted from the adsorbent using supercritical carbon dioxide. An apparatus was constructed to facilitate the extraction and recovery of the desired analytes. The resulting extracts were analyzed using gas chromatography/mass spectrometry (GC/MS) or high performance liquid chromatography (HPLC) techniques. Results are presented for a series of analytes representative of common commercial pesticides or herbicides.
Hybrid inorganic/organic adsorbents based on alumina and 4-aminoantipyrene were synthesized, characterized and potentially applied to remove and preconcentrate Pb(II), Cu(II) and Cr(III) from industrial wastewater and drinking tap water via static and dynamic solidphase techniques. Hybrid inorganic/organic adsorbents were identified as strongly resistive to acid leaching in pH 1-7 and thermally stable up to 350^oC. Heavy metal binding performance was evaluated and found to exhibit strong capability and selectivity for removal of heavy metal ions such as Pb(II), Cu(II) and Cr(III) under optimized pH and contact time. The contribution of inorganic portion of the hybrid was strongly observed when low concentration levels (mgml^-^1 and ngml^-^1) of metal ions were used, while the contribution...
This study has focused on developing two nanoporous titania adsorbents (NTA) to enhance removal efficiency of adsorption process for As(V) by characterizing the effects of pH and phosphate concentration on their sorption capacities and behaviors. One type of adsorbent is a mesoporous titania (MT) solidphase and the other is group of a highly ordered mesoporous silica solids (SBA-15) that can incorporate different levels of reactive titania sorption sites. Microscopic analysis showed that Ti(25)-SBA-15 (Ti/SBA=0.25g/g) had titania nanostructured mesopores that do not rupture the highly ordered hexagonal silica framework. However, MT has disordered, wormhole-like mesopores that are caused by interparticle porosity. Adsorption experiments showed that Ti(25)-SBA-15 had a greater sorption capa...
A fully automated cold fiber solidphase microextraction device has been developed by coupling to a GERSTEL multipurpose (MPS 2) autosampler and applied to the analysis of volatiles and semi-volatiles in aqueous and solid matrices. The proposed device was thoroughly evaluated for its extraction performance, robustness, reproducibility and reliability by gas chromatograph/mass spectrometer (GC/MS). With the use of a septumless head injector, the entire automated setup was capable of analyzing over 200 samples without any GC injector leakages. Evaluation of the automated cold fiber device was carried out using a group of compounds characterized by different volatilities and polarities. Extraction efficiency as well as analytical figures of merit was compared to commercial solidphase microex...
We have prepared a highly selective and efficient sorbent for the simultaneous separation and preconcentration of lead and cadmium ions from milk and water samples. An ionic liquid was deposited on the surface of magnetic nanoparticles (IL-MNPs) and used for solidphaseextraction of these ions. The IL-MNPs carrying the target metals were then separated from the sample solution by applying an external magnetic field. Lead and cadmium were almost quantitatively retained by the IL-MNPs, and then eluted with nitric acid. The effect of different variables on solidphaseextraction was investigated. The calibration curve is linear in the range from 0.3 to 20 ng mL?1 of Cd(II), and from 5 to 330 ng mL?1 of Pb(II) in the initial solution. Under optimum conditions, the detection limits are 1.61 an...
The detection of trace levels of pharmaceuticals in environmental matrices requires an analyte pre-concentration procedure to obtain the required sensitivity for quantitative determination. This research aims to develop a simple automated analytical method based on C18 thin film solidphase microextraction (TF-SPME) for the simultaneous extraction of pharmaceutical compounds detected in surface waters. As a sample preparation method, solidphase microextraction, is a rapid, environmentally friendly, and a sensitive analytical technique which isolates and pre-concentrates trace organic pollutants from environmental water samples in a single step. High throughput analysis was achieved with the use of a robotic auto sampler which enabled parallel analyte extraction in a 96-well plate format. ...
Nitrosamines are a group of carcinogens that have been found in various latex products. Methods have been developed for extraction, concentration and detection of simulant migration of volatile nitrosamines from latex gloves and balloons. After glove samples or balloon samples were treated with artificial sweat and artificial saliva, headspace solid-phase microextraction and gas chromatography with mass spectrometer detection were performed. Eight volatile nitrosamines were extracted by a fused silica fiber coated with carboxen-polydimethylsioxane, and solid-phase microextraction conditions were optimized. The developed method was successfully used to analyze simulant migration of volatile nitrosamines from latex gloves and balloons. The described methods are rapid and simple, with adequate sensitivity and without organic solvent. PMID:22634193
The molecularly imprinted polymers (MIPs) are used as the base material of solidphaseextraction (SPE) for the separation and concentration of the propachlor herbicide (Prop) in different environmental matrix. Accordingly, we prepared MIPs on the surface of modified silica gel using propachlor as a template, acrylamide (AA) as functional monomers, ethylene glycol dimethacrylate (EGDMA) as a cross-linker and 2,2-azo-bis-isobutyronitrile (AIBN) as an initiator. The MIP structure was characterised using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Synthesised MIPs had a specific ability to detect the template Prop. The high selectivity solidphaseextraction cartridges of molecularly imprinted polymers (MISPE) containing MIP Prop particles were prep...
In this paper, a highly selective sample cleanup procedure combining molecular imprinting technique (MIT) and solid-phaseextraction (SPE) was developed for the isolation of malachite green in seawater and seafood samples. The molecularly imprinted polymer (MIP) was prepared using malachite green as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer. The imprinted polymer and non-imprinted polymer were characterized by scanning electron microscope and static adsorption experiments. The MIP showed a high adsorption capacity and was used as selective sorbent for the SPE of malachite green. An off-line molecularly imprinted solid-phaseextraction (MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of malachite green in seawater and seafood samples was also established. Finally, five samples were determined. The results showed that malachite green concentration in one seawater sample was at 1.30?gL(-1) and the RSD (n=3) was 4.15%. PMID:23122763
A new Fe3O4/polyaniline nanoparticle (PANI) material has been successfully developed as magnetic solid-phaseextraction sorbent in dispersion mode for the determination of methylmercury (MeHg) in aqueous samples, via quantification by gas chromatography/mass spectrometry (GC-MS). The resultant core-shell magnetic solid-phaseextraction nanoparticle (MSPE-NP) sorbent was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and Fourier transform-infrared (FTIR) spectroscopy. Fe3O4/PANI composites showed fibrous structure with diameters between 50 and 100nm for fibers. The MSPE-NP process involved the dispersion of the Fe3O4/PANI nanoparticles in water samples with sonication, followed by magnetic aided retrieval of the sorbent and then, solvent (hex...
An efficient molecularly imprinted solidphaseextraction (MISPE)-spectrofluorimetric method was developed to sensitively determine danofloxacin (DAN) in milk samples. Solidphaseextraction procedure using MISPE cartridges was first performed on milk samples and then spectrofluorimetric determination was done at 546nm using an excitation wavelength of 285nm in presence of terbium and sodium dodecyl benzene sulfonate (SDBS). It was found that SDBS significantly enhanced the fluorescence intensity of the DAN-Tb3+ complex. Various factors affecting the fluorescence intensity of DAN-Tb3+-SDBS system were studied and conditions were optimized. The enhanced fluorescence intensity of the system (DF) showed a good linear relationship with the concentration of DAN over the range of 8.4x10-9-3.4x10...
In the present work the simultaneous extraction for the multiresidue determination in wastewater samples of organic compounds such as polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), pesticides, polycyclic aromatic hydrocarbons (PAHs), phthalate esters (PEs), alkylphenols (APs), bisphenol A (BPA) or hormones included in different lists of priority and emerging pollutants because of their action as endocrine disrupting compounds (EDCs) was developed. Different solidphaseextraction (SPE) variables such as the nature of the solidphase (Oasis-HLC, C18 and Lichrolut), the sample volume, the addition of MeOH and NaCl, the pH of the water phase and the volume of the eluent solvent were optimized in order to analyze simultaneously the priority and emerging families of pollutan...
A method for assessment of toxicity of nonvolatile organic chemicals contaminants in groundwater polluted with landfill leachate has been evaluated. The biotests utilized were composed of an algal growth inhibition test (Selenastrum capricornutum), a daphnia immobilization test (Daphnia magna), and a bacterial genotoxicity test (umuC, Salmonella typhimurium). The feasibility of the selected biotests was investigated for a series of groundwater samples collected along pollution gradients downstreams of two landfills in Jutland, Denmark. Two different approaches were used, direct toxicity testing of whole groundwater samples, and toxicity testing of concentrates obtained by solid-phaseextraction. Direct testing of whole groundwater samples produced toxic responses, but the complex sample matrix masked the toxicity of the organic chemical contaminants of interest. Solid-phaseextraction was used successfully as an on-site method that eliminated ion toxicity and produced biotest responses that reflected the toxicity of the nonvolatile organic chemical contaminants in the groundwater.
The monitoring of additives in electrolytic baths is a fundamental task for proper coatings. Among the additives used in zinc baths, benzylideneacetone (BDA), benzoic acid (BA) and polyethylene glycol 400 (PEG400) are easily found. This paper deals with the possibilities of handling the bath sample before it is taken to a gas chromatograph (GC) in order to follow the additives concentration along the bath life. The applied techniques include solidphaseextraction (SPE), solvent extraction (SE), static headspace (SHS), direct injection (DI) and headspace solidphase microextraction (HS-SPME) recoveries up to 6:1, 14:1, 9:1, 1:1 and 80:1 respectively have been obtained. Internal standards have been found for every case. Advantages and disadvantages of the techniques are collected. In this p...
This paper describes a fully automated online method for solid-phaseextraction coupled with liquid chromatography and tandem mass spectrometry using atmospheric pressure ionization (LC-LC-APPI-MS/MS) to simultaneously detect selected dissolved natural and synthetic hormones at concentrations as low as 5ng/L from aqueous matrices. The method shows excellent performance for the direct analysis of water and wastewater with respect to calibration curve linearity, analytic specificity, sensitivity, and carryover, as well as overall method accuracy and precision. With a runtime of 15min, a minimum of 200 samples were analyzed using a single online solid-phaseextraction (SPE) column without noticeable differences in system performance. Because of the ruggedness and simplicity of this system, ge...
Micropipette-tip solidphaseextraction systems are common in proteomic analyses for desalting and concentrating samples for mass spectrometry, removing interferences, and increasing sensitivity. These systems are inexpensive, disposable, and highly efficient. Here we show micropipette-tip solidphaseextraction is a direct sample preparation method for {sup 14}C-accelerator mass spectrometry (AMS), removing salts or reagent from labeled macromolecules. We compared loading, recovery and desalting efficiency in commercially available SPE micro-tips using {sup 14}C-labeled peptides and proteins, AMS, and alpha spectrometry ion energy loss quantitation. The polypropylene in the tips was nearly {sup 14}C-free and simultaneously provided low-background carrier for AMS. The silica material did not interfere with the analysis. Alpha spectrometry provided an absolute measurement of desalting efficiency.
An analytical procedure that enables routine analysis for trace determination of six anabolic macrocyclic lactones (zearalenone, alpha- and beta-zearalenol, zearalanone, zeranol, and taleranol) in sewage treatment plant (STP) samples has been developed. The method uses solid-phaseextraction, followed by high-performance liquid chromatography with on-line tandem mass spectrometry using atmospheric pressure chemical ionization (LC/APCI-MS/MS). The extraction of these compounds from filtered water samples was performed off-line with C(18) solid-phase cartridges. The detection was achieved by isocratic reversed-phase high-performance liquid chromatography coupled with an heated nebulizer (HN) APCI interface operating in negative ion mode. Mean recovery of the analytes in STP effluent samples generally exceeded 81%. This method was used to determine the occurrence of target analytes in the aquatic environment. In the selected STP effluent samples, zearalenone and alpha-zearalenol were detected in the ng/L range. PMID:11223963
An analytical method for the determination of 6 acetamide herbicides (acetochlor, alachlor, dimethenamid, flufenacet, metolachlor, and propachlor) and 16 of their degradation products in natural water samples using solid-phaseextraction and liquid chromatography/mass spectrometry is described in this report. Special consideration was given during the development of the method to prevent the formation of degradation products during the analysis. Filtered water samples were analyzed using octadecylsilane as the solid-phaseextraction media on online automated equipment followed by liquid chromatography/mass spectrometry. The method uses only 10 milliliters of sample per injection. Three different water-sample matrices, a reagent-water, a ground-water, and a surface-water sample spiked at 0.10 and 1.0 microgram per liter, were analyzed to determine method performance.\\r\
A highly sensitive, selective and rapid method for the determination mgL^-^1 level of Au(III) based on the rapid reaction of Au(III) with 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) and the solidphaseextraction of the colored complex with a reversed phase polymer-based C18 cartridge have been developed. The DCHNAQ reacted with Au(III) to form a violet complex of a molar ratio 3:1 [DCHNAQ to Au(III)] in the presence of 5.0M of phosphoric acid solution and Triton X-100 medium. This complex was enriched by the solidphaseextraction with a polymer-based C18 cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 2.73x10^5lmol^-^1cm^-^1 at 633nm in the measured solution. The system obeys Beer's law in the range of 0.02-1.30mgm...
The influence of saliva on aroma release from white and red wines was studied in a model mouth system. Aroma compounds were analysed in the dynamic headspace of wines by solidphase micro extraction/gas chromatography with flame ionization detection. Volatile compounds were identified by solidphase micro extraction/gas chromatography-mass spectrometry, resulting in a total of 43 compounds in white wine and 41 in red wine. The results showed a greater influence of saliva on aroma release in white wine than red wine. In white wine treated with human saliva, esters and fusel alcohols, responsible for fruity and fusel oil odours, were reduced of 32-80%; by contrast, the concentration of 2-phenylethanol and furfural, responsible for rose and toasted almond notes, increased by 27% and by 155%, ...
A method is described for removing solid fines in an extraction of bitumen from a carbonaceous solid or carbonaceous liquid containing extractable bitumen comprising; (a) forming a mixture comprising dissolved bitumen, about 5 to about 25 weight % undissolved bitumen, solid particle fines, and solvent wherein the about 5 to about 25 weight % undissolved bitumen is sufficient to settle from the mixture and remove the solid particle fines; (b) permitting the undissolved bitumen to settle with at least a portion of the solid fines agglomerating and settling with the undissolved bitumen to form a lower solidphase; (c) separating an upper dissolved bitumen solvent liquid phase from the lower solidphase; and (d) separating the dissolved bitumen from the solvent.
PCBs are among the most persistent and widely distributed pollutants in the global ecosystem and therefore it is of great importance for both human and environmental health to develop practical analytical systems to detect them. In this context, this work presents the application of an electrochemical immunosensor based on Screen-Printed Carbon-based Electrodes as transducers with antibody-coated magnetic microparticles as a solidphase. The immunoassay was based on direct competition between the analyte present in the samples and an alkaline phosphatase-labeled tracer. The product of the enzymatic reaction between AP and its substrate (?-naphthyl phosphate) was detected using differential pulse voltammetry. Sample extraction and clean-up was achieved using SolidPhaseExtraction. De...
The novel molecularly imprinted microsphere (MIM) that could be applied as special sorbent was synthesized by aqueous suspension polymerization using 1,1-bis(4-chlorophenyl)-1,2,2,2-tetrachloroethane (?-chloro-DDT) as the dummy template. The obtained MIM exhibited good recognition and selectivity to dicofol and it was successfully applied as selective sorbent of solid-phaseextraction for the determination of dicofol from aquatic products. At the optimum conditions of the molecularly imprinted solid-phaseextraction (MISPE) coupled with GC-ECD, good linearity for dicofol was achieved in a range of 0.4-100 ng g(-1) (r(2)=0.9995) and the recoveries at three spiked levels were ranged from 85.8% to 101.2% for aquatic products with the relative standard deviation (RSD) less than 5.6%. The presented MISPE-GC-ECD method exhibited the advantages of simplicity, selectivity and sensitivity, and could be potentially applied to the determination of dicofol in complicated aquatic products. PMID:21872064
The use of custom-made polymeric materials with high selectivities as target molecules in solid-phaseextraction (SPE), known as molecularly imprinted solid-phaseextraction (MISPE), is becoming an increasingly important sample preparation technique. However, the potential risk of leakage of the imprinting molecules during the desorption phase has limited application. The use of a mimicking template, called a dummy molecular imprinting polymer (DMIP), that bears the structure of a related molecule and acts as a putative imprinting molecule may provide a useful solution to this problem. In the current study, cyproheptadine (CPH) and azatadine (AZA) were used as templates in the development of an MIP and DMIP for acrylic acid and methacrylic acid monomers. Our results indicate that DMIPs hav...
The novel molecularly imprinted microsphere (MIM) that could be applied as special sorbent was synthesized by aqueous suspension polymerization using 1,1-bis(4-chlorophenyl)-1,2,2,2-tetrachloroethane (a-chloro-DDT) as the dummy template. The obtained MIM exhibited good recognition and selectivity to dicofol and it was successfully applied as selective sorbent of solid-phaseextraction for the determination of dicofol from aquatic products. At the optimum conditions of the molecularly imprinted solid-phaseextraction (MISPE) coupled with GC-ECD, good linearity for dicofol was achieved in a range of 0.4-100ngg^-^1 (r^2=0.9995) and the recoveries at three spiked levels were ranged from 85.8% to 101.2% for aquatic products with the relative standard deviation (RSD) less than 5.6%. The presente...
This paper describes the development and validation of an analytical methodology to determine the presence of four PAHs: benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene in cultures of the green microalgae Selenastrum capricornutum. The metabolites of benzo[a]pyrene (BaP), 4,5-dihydrodiol benzo[a]pyrene, 9,10-dihydrodiol benzo[a]pyrene, 3-hydroxy benzo[a]pyrene and 9-hydroxy benzo[a]pyrene were also included. The methodology consisted of three parts: (1) separation of liquid media from biomass samples by centrifugation of pure cultures, (2) off-line extraction of analytes from biomass by a miniaturized matrix solidphase dispersion (MSPD) method and from liquid media by a solidphaseextraction (SPE) method and (3) on-line SPE preconcentration and analysis ...
A new solidphaseextraction method for rapid high performance liquid chromatography?UV determination of mitragynine in plasma has been developed. Optimal separation was achieved with an isocratic mobile phase consisting of acetonitrile?ammonium acetate buffer, 50?mM at pH 5.0 (50:50, v/v). The method had limits of detection and quantification of 0.025 and 0.050??g/mL, respectively. The method was accurate and precise for the quantitative analysis of mitragynine in human and rat plasma with within-day and between-day accuracies between 84.0 and 109.6%, and their precision values were between 1.7 and 16.8%. Additional advantages over known methods are related to the solidphaseextraction technique for sample preparation which yields a clean chromatogram, a short total analysis time, requir...
Solidphase microextraction (SPME) is an increasingly common method of sample isolation and enhancement. SPME is a convenient and simple sample preparation technique for chromatographic analysis and a useful alternative to liquid-liquid extraction and solidphaseextraction. SPME is speed and simply method, which has been widely used in environmental analysis because it is a rather safe method when dealing with highly toxic chemicals. A combination of SPME and gas chromatography (GC) permits both the qualitative and quantitative analysis of toxic industrial compounds, pesticides and chemical warfare agents (CWAs), including their degradation products, in air, water and soil samples. This work presents a combination of SPME and GC methods with various types of detectors in the analysis of C...
The cost of uranium recovered from seawater was estimated to extract the technical problems in the practical application of the fibrous amidoxime adsorbent synthesized by radiation graftpolymerization. Each cost of the adsorbent production, the dipping in seawater for uranium absorption, and the uranium elution from the adsorbent was estimated in three different mooring systems of a buoy, floating body, and chain binding system. The recovery cost was estimated to be 5-10 times of that from mining uranium. More than 80% of the total cost was occupied by the cost for marine equipment for mooring the adsorbents in seawater, which is owing to a weight of metal cage for adsorbents. Thus, the cost can be reduced to half by the reduction of the equipment weight to 1/4. The improvement of adsorbent ability is research subjects in the future also, since the cost directly depends on the adsorbent performance. (author)
Three methods to determine the bioavailability of polycyclic aromatic hydrocarbons were modified and developed for application to polychlorinated biphenyls (PCBs). Water/XAD desorption and selective supercritical fluid extraction methods were developed to determine the rapidly-released fraction of PCBs from contaminated soils and sediments. A method to determine PCBs in sediment pore water based on solid-phase microextraction was also developed that is capable of determining low pg/mL concentrations with water samples as small as 1.5 mL.
A novel gas chromatography-mass spectrometric (GC-MS) method was developed to confirm and identify metoprolol and its metabolites by double derivatization with S-(-)menthyl chloroformate [(-)-MCF] and N-methyl(trimethylsilyl-trifluoroacetamide) (MSTFA). This is the first report, which describes the simultaneous identification of metoprolol, its one major acidc and other basic metabolites in human urine based on solid-phaseextraction with C{sub 18} reversed-phase cartridges. 12 refs., 4 figs.
Solid-phaseextraction is an attractive approach in the preparation of many kinds of samples prior to analysis; highly selective sorbents are desirable for this purpose. The objective of this review is to provide updated information about carbon-based sorbents, their interaction modes and potential application for the concentration and separation of metal ions from environmental samples prior to their determination. New selective phases such as fullerenes and carbon nanotubes are described. Selected examples illustrate the potential of these sorbents.
An analytical scenario has been developed for the determination of some tropane alkaloids in Datura metel, including sample preparation by solid-phaseextraction and chromatographic (GC and HPLC) determination of the analytes. The proposed scenario is rapid and provides the complete recovery of alkaloids; the analytical range for atropine and scopolamine is 0.01?30 mg/mL. The procedure ensures the simultaneous determination of compounds from other classes of substances.
Internation Flavors and Fragrances Inc. proprietary research technology, SolidPhase Micro Extraction (SPME) utilizes a special fiber needle placed directly next to the bloom of the living flower to collect the fragrance molecules. SPME was used in the Space Flower experiment aboard STS-95 space shuttle mission, after which Dr. Braja Mookherjee (left) and Subha Patel of IFF will analyze the effects of gravity on the Overnight Scentsation rose plant.
The stereocontrolled synthesis of (E)-configured styrenes via Pd(0)-catalyzed cross-couping of (E)-alkenylgermanes with aryl bromides is described. The germanes employed have bis(naphthalen-2-ylmethyl) substitution to allow photooxidative activation toward coupling and a C8F17-fluorous tag to facilitate purification by fluorous solid-phaseextraction (F-SPE). The selectivities obtained suggest that a germyl-Stille rather than Heck-type mechanism predominates in the coupling step.
An HPLC undergraduate experiment on the analysis of traditional Chinese medicine (TCM) has been developed. Two commonly used herbs ("glycyrrhizae radix" and "cinnamomi ramulus") are studied. Glycyrrhizin, cinnamic acid, and cinnamaldehyde are chosen as markers for the herbs. The dried herbs in their natural state and a TCM preparation in powder form are analyzed. Gradient elution with diode-array detection is used for the separation and identification of the markers. Solid-phaseextraction is employed for cleaning the sample solutions. (Contains 3 figures.)
A complete remote control system was constructed for production of the PET 5-HT{sub 2A} ligand [{sup 18}F]altanserin by nitro-for-fluoro exchange. Comparing with published methods, the key features include (1) conducting azeotropic distillation and nucleophilic displacement in an open vessel heated by a commercial microwave oven; (2) purifying the product by a single HPLC procedure and (3) removing HPLC solvent by solidphaseextraction. The preparation took 114 min with 23% yield and high quality.
Direct determination of cortisol (F) in human saliva and its clinical applications were investigated. For this purpose, a solidphase radioimmunoassay (RIA) was carried out. The detection limits for F in 50 and 400 ..mu..l of saliva were 0.125 and 0.0156 ..mu..g/100 ml, respectively, and the intra-assay coefficient of variation was 5.9-12.2%. Salivary F levels measured by this method were in good agreement with those by the RIA after extraction with dichlormethane reported previously.
This work presents an effective sample preparation method for the evaluation of seven pharmaceutical compounds belonging to different therapeutic classes in purified water from wastewater treatment plants (WWTPs). The target compounds include caffeine (stimulant), nicotine (stimulant), atenolol (beta blocker), metamizole (anti-inflammatory and analgesic), fluoxetine (antidepressant), paraxanthine (stimulant) and clofibric acid (lipid regulator). Solid-phaseextraction (SPE) and liquid chromatography-mass spectrometry (LC-MS) were selected as extraction and detection techniques, respectively. A detailed study of the experimental conditions of extraction was performed. Under optimal conditions, recoveries obtained were in the range of 21% to 100%, and the relative standard deviations were be...
Sample preparation is an important step for the determination of phenolic compounds in biological samples. Different extraction methods have been tested to determine phenolic compounds and their metabolites in plasma by nano-liquid chromatography coupled to electrospray ionisation-time-of-flight mass spectrometry (nanoLC-ESI-TOF-MS). The sample treatment optimisation was performed using commercial foetal bovine serum spiked with representative phenolic standards, namely naringenin, luteolin, verbascoside, apigenin, rutin, syringic acid and catechin. Different protein-precipitation conditions were evaluated as well as enzymatic digestion with trypsin and solid-phaseextraction using different phases such as C-18, ABN and ENV+, working at different pH values. The optimum extraction procedure...
A new multiresidue method for the efficient screening, identification and quantification of over 160 pesticides belonging to different chemical classes in red, rose and white wines have been developed. The analysis was based on gas chromatographic-tandem quadrupole mass spectrometric determination (GC-QqQ-MS/MS). An optimization strategy involved the selection of buffering conditions and sorbents for dispersive-solidphaseextraction (dispersive-SPE) in order to achieve acceptably high recoveries and reduce co-extractives in the final extracts. As a result, the optimized procedure allowed us to obtain consistent recoveries of the target pesticides including problematic ones such as captan, chlorothalonil, dichlofluanid, folpet and tolylfluanid. The attained recoveries were typically betwee...
In the present study, a new analytical method has been developed for the simultaneous quantification of 15 organophosphorus pesticides, including some of their metabolites, (disulfoton-sulfoxide, ethoprophos, cadusafos, dimethoate, terbufos, disulfoton, chlorpyrifos-methyl, malaoxon, fenitrothion, pirimiphos-methyl, malathion, chlorpyrifos, terbufos-sulfone, disulfoton-sulfone and fensulfothion) in three different types of commercial cereal-based baby foods. Dispersive solid-phaseextraction (dSPE) with multi-walled carbon nanotubes (MWCNTs) was used together with gas chromatography with nitrogen phosphorus detection. Most favorable conditions involved a previous ultrasound-assisted extraction of the sample with acetonitrile containing formic acid. After evaporation of the extract and redi...
Ionic liquids (ILs) have been the focus of many scientific investigations including the field of analytical microextractions. ILs have many advantages over traditional organic solvents making them excellent candidates as extraction media for a variety of microextraction techniques. Many physical properties of ILs can be varied, and the structural design and make-up can be tuned to impart desired functionality for enhancement of analyte extraction selectivity, efficiency, and sensitivity. This paper provides a brief overview of ionic liquids and highlights trends in three important sample-preparation techniques, namely, single drop microextraction, solid-phase microextraction, and dispersive liquid-liquid microextraction in terms of performing task-specific extractions using these highly versatile solvents. (orig.)
A headspace solidphase microextraction (HS-SPME) method coupled with gas chromatography and MS detection (GC/MS) was optimized for the simultaneous determination of 21 target Pharmaceuticals and Personal Care Products (PPCPs) in water samples. The analytes included fragrances, UV-filters, antiseptics, estrogens, anti-inflammatory drugs, and pesticides. An on-fiber SPME derivatization, using silyl reagents, was performed for the analysis of more polar acidic compounds. An experimental design approach was applied to systematically investigate and optimize the operative parameters affecting the extraction recovery, namely: extraction temperature and time, derivatization time, desorption temperature and time. The optimum operating conditions were: extraction time of 125?min at a temperature o...
The determination of widely used anaesthetic and analgesic drugs in biological fluids is of major clinical importance. Typical methods used for sample preparation employ liquid-liquid extraction protocols which are complex, costly, not handy and not amenable to automation. In the present communication, we report the development of a methodology that employs headspace solid-phase microextraction (HS-SPME) for the determination of four anaesthetic (lidocaine, midazolam, diazepam and ketamine) and three analgesic drugs (fentanyl, remifentanyl and codeine) in human urine. Important parameters controlling SPME were studied: selection of SPME fibre, type and amount of salt added, preheating and extraction time, extraction temperature, sample volume and desorption time. GC with nitrogen phosphoru...
During the last few years, there has been a tremendous increase in consumption of pomegranate fruit and juice. Nevertheless, very little is yet known regarding the volatile constituents that determine the unique aroma of pomegranate fruit. We extracted aroma volatiles from fresh â?????Wonderfulâ?????? pomegranate juice using solvent-assisted flavour evaporation (SAFE) and headspace solid-phase micro-extraction (HS-SPME) methods, and applied gas chromatographyâ??????olfactometry (GCâ??????O) (â?????sniffingâ??????) combined with gas chromatographyâ??????mass spectrometry (GCâ??????MS) analysis, in order to identify volatile aroma-active compounds. In addition, we performed stir bar sorptive extraction (SBSE) of pomegranate aroma volatiles, coupled with GCâ??????MS analysis, in order to assi...
A novel validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) procedure was developed and fully validated for the simultaneous determination of nicotine-N-b-d-glucuronide, cotinine-N-oxide, trans-3-hydroxycotinine, norcotinine, trans-nicotine-1'-oxide, cotinine, nornicotine, nicotine, anatabine, anabasine and cotinine-N-b-d-glucuronide in human plasma or urine. Target analytes and corresponding deuterated internal standards were extracted by solid-phaseextraction and analyzed by LC-MS/MS with electrospray ionization (ESI) using multiple reaction monitoring (MRM) data acquisition. Calibration curves were linear over the selected concentration ranges for each analyte, with calculated coefficients of determination (R^2) of greater than 0.99. The total extraction recovery (%) wa...
A new extraction technique based on the off-line combination of pressurized-liquid with solid-phaseextraction (PLE-SPE) is described. The method was used for the extraction of bioactive phenolic acids (protocatechuic, p-hydroxybenzoic, 2,3-dihydroxybenzoic, chlorogenic, vanillic, caffeic, p-coumaric, salicylic acid), cinnamic acid and hydroxybenzaldehydes (p-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, vanillin) from in vitro culture of two freshwater algae (Anabaena doliolum and Spongiochloris spongiosa) and from food products of marine macroalgae Porphyra tenera (nori) and Undaria pinnatifida (wakame). For the identification and quantification of the compounds the molecular ions [M-H]- and specific fragments were analyzed by quadrupole mass spectrometry analyzer connected on-line wit...
A simple and efficient method based on headspace solid-phase microextraction (HS-SPME) followed by gas chromatography coupled to flame photometric detection was developed for the simultaneous determination of five volatile sulfur compounds (VSCs; hydrogen sulfide (H2S), methanethiol (MeSH), dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS)) in hyper-eutrophic freshwater lakes suffering from black water agglomerate. Carboxen/polydimethylsiloxane (CAR/PDMS) fiber was selected for the extraction of VSCs, and various parameters, such as the stirring rate, sample volume, ionic strength, duration and temperature of extraction and the duration and temperature of desorption, were optimized for extraction efficiency. The linearity spanned approximately three orders of...
Undoubtedly, whole blood and vitreous humor have been biological samples of great importance in forensic toxicology. The determination of opiates and their metabolites has been essential for better interpretation of toxicological findings. This report describes the application of experimental design and response surface methodology to optimize conditions for enzymatic hydrolysis of morphine-3-glucuronide and morphine-6-glucuronide. The analytes (free morphine, 6-acetylmorphine and codeine) were extracted from the samples using solid-phaseextraction on mixed-mode cartridges, followed by derivatization to their trimethylsilyl derivatives. The extracts were analysed by gas chromatography–mass spectrometry with electron ionization and full scan mode. The method was validated for both s...
A headspace-solidphase microextraction-gas chromatography-mass spectrometric (HS-SPME-GC-MS, hereafter abbreviated as "SPME") method was developed for dedicated organophosphorus (OP) pesticides assessment in multiple vegetable and fruit commodities. Specific extraction variables were optimised to achieve harmonised extraction performance of eleven OPs in a great span of seven characteristic commodities cataloged in Codex Alimentarius Commission. Comprehensive validation study confirmed analytical robustness of the SPME treatment in turnip, green cabbage, French beans, eggplant, apple, nectarine and grapes. Based on range-specific evaluation, extraction of individual OPs was characterised by sub-ppb level sensitivity and a wide 0.01-2.5mgL-1 dynamic range. Effective sample clean-up afforde...
Abstract in english This work was aimed on optimization of the matrix solid-phase dispersion (MSPD) technique using gas chromatography for analyzing residues of chlorpyriphos, ?-cyhalothrin, cypermethrin and deltamethrin in tomatoes. The results showed that silica was more efficient for the clean up of extracts, but florisil provided the highest recovery rates. A 2³ complete factorial design was carried out to evaluate the absorbent/sample ratio, presence of co-column (silica) and ultr (more) asonic bath on the extraction rate. The percentage of extraction of the pesticides chlorpyriphos, ?-cyhalothrin, cypermethrin and deltamethrin were 64.7, 88.3, 99.2 and 89.2%, respectively, with relative standard deviations below 5%.
A genuine analytical method to determine native steroids (pregnenolone, progesterone, dehydroepiandrosterone, androstenedione, testosterone, dihydrotestosterone, estrone, 17b-estradiol, and 17a-estradiol) and one anthropogenic steroid (ethynylestradiol) in environmental solid samples is presented. In summary, the sample preparation was systematically evaluated with testing different solvents and a suite of solidphaseextraction materials. The optimized method utilizes the pressurized liquid extraction (PLE) technology with automated (integrated) clean-up combined with an additional off-line multi-step clean-up. The sample extracts were derivatized and analyzed utilizing a gas chromatography triple quadrupole mass spectrometry technology. This method is applicable on all types of environmental solid samples (e.g., biosolids, soils and sediments).
Novel sampling and detection methods using desorption electrospray ionization (DESI) are examined in the detection of explosives (RDX, TNT, HMX, and TNB) and agricultural chemicals (atrazine, alachlor and acetochlor) from aqueous matrices and authentic contaminated groundwater samples. DESI allows analysis of solid and liquid compounds directly from surfaces of interest with little or no sample preparation. Significant savings in analysis time and sample preparation are realized. The methods investigated here include (i) immediate analysis of filter paper wetted with contaminated water samples without further sample preparation, (ii) rapid liquid-liquid extraction (LLE), and (iii) analyte extraction from contaminated groundwater samples on-site using solid-phaseextraction (SPE) membranes,...
A method for the simultaneous determination of seven commonly used artificial sweeteners in water is presented. The analytes were extracted by solidphaseextraction using Bakerbond SDB 1 cartridges at pH 3 and analyzed by liquid chromatography electrospray ionization tandem mass spectrometry in negative ionization mode. Ionization was enhanced by post-column addition of the alkaline modifier Tris(hydroxymethyl)amino methane. Except for aspartame and neohesperidin dihydrochalcone, recoveries were higher than 75% in potable water with comparable results for surface water. Matrix effects due to reduced extraction yields in undiluted waste water were negligible for aspartame and neotame but considerable for the other compounds. The widespread distribution of acesulfame, saccharin, cyclamate, ...
Organic micropollutants such as pharmaceuticals, perfluorinated compounds (PFCs), and pesticides, are important environmental contaminants. To obtain more information regarding their presence in marine organisms, an increasing demand exists for reliable analytical methods for quantification of these micropollutants in biotic matrices. Therefore, we developed extraction procedures and new analytical methods for the quantification of 14 pesticides, 10 PFCs, and 11 pharmaceuticals in tissue of marine organisms, namely blue mussels (Mytilus edulis). This paper presents these optimized analytical procedures and their application to M. edulis, deployed at five stations in the Belgian coastal zone. The methods consisted of a pressurized liquid extraction and solid-phaseextraction (SPE) followed ...
Abstract in english Supercritical CO2 extraction of essential oil from Thymus vulgaris leaves was studied using experimental data recently obtained in the Florys S.p.A. laboratory. Mass transfer coefficients in the supercritical and solidphases from extraction curves at 40°C and 20 MPa were evaluated using a mathematical model based on the local adsorption equilibrium of essential oil on lipid in leaves. The adsorption equilibrium constant was fitted to these experimental data, and interna (more) l and external mass transfer resistances were calculated, allowing identification of the mechanism controlling the extraction process.
A liquid chromatography?tandem mass spectrometry method for the analysis of seven antiviral drugs, zanamivir, ribavirin, oseltamivir, oseltamivir carboxylate, amantadine, rimantadine and arbidol, in poultry muscle is reported. The antiviral drugs were extracted from the homogenized poultry muscle sample using methanol. The extract was purified using tandem solid-phaseextraction combining a cation exchange cartridge and a phenylboronic acid cartridge. To prevent excessive matrix effects, the analytes were separated from the matrix constituents using a column-switch liquid chromatography system combining a reversed-phase and a Hypercarb analytical column. Detection was carried out using tandem mass spectrometry. The method was fully validated according to 2002/657/EC [1] and proved to be ad...
We developed an automated and multifunctional microfluidic platform based on DropLab to perform flexible generation and complex manipulations of picoliter-scale droplets. Multiple manipulations including precise droplet generation, sequential reagent merging, and multistep solid-phaseextraction for picoliter-scale droplets could be achieved in the present platform. The system precision in generating picoliter-scale droplets was significantly improved by minimizing the thermo-induced fluctuation of flow rate. A novel droplet fusion technique based on the difference of droplet interfacial tensions was developed without the need of special microchannel networks or external devices. It enabled sequential addition of reagents to droplets on demand for multistep reactions. We also developed an effective picoliter-scale droplet splitting technique with magnetic actuation. The difficulty in phase separation of magnetic beads from picoliter-scale droplets due to the high interfacial tension was overcome using ferromagnetic particles to carry the magnetic beads to pass through the phase interface. With this technique, multistep solid-phaseextraction was achieved among picoliter-scale droplets. The present platform had the ability to perform complex multistep manipulations to picoliter-scale droplets, which is particularly required for single cell analysis. Its utility and potentials in single cell analysis were preliminarily demonstrated in achieving high-efficiency single-cell encapsulation, enzyme activity assay at the single cell level, and especially, single cell DNA purification based on solid-phaseextraction. PMID:21866917
A capillary zone electrophoresis method is presented for the analysis of six biomarkers of polycyclic aromatic hydrocarbons in urine samples. Baseline resolution of 2-hydroxyfluorene, 2-hydroxynaphthalene, 1-hydroxypyrene, 9-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene, 4-hydroxybenzo[a]pyrene and 5-hydroxybenzo[a]pyrene was achieved in approximately 17 min with a 20 mM borate buffer prepared in 50% methanol-water (volume/volume). Competitive limits of detection were obtained for all the studied metabolites using commercial instrumentation equipped with an ultraviolet-visible absorption detector. Detection at the sub-parts-per-billion concentration levels was made possible via sample pre-concentration based on solid-phaseextraction and sample stacking. Solid-phaseextraction was performed with the aid of a twelve port vacuum manifold. Sample stacking was carried out in methanol, i.e. the eluting solvent from the solid-phaseextraction procedure. To the extent of our literature search, this is the first application of sample stacking to the analysis of monohydroxy-polycyclic aromatic hydrocarbons in urine samples. Metabolite recoveries varied from 93.2 ± 7.7% (5-hydroxybenzo[a]pyrene) to 108.7 ± 7.8% (2-hydroxynaphthalene). Limits of detection were at the trace level ranging from 0.99 ng mL(-1) (3-hydroxybenzo[a]pyrene) to 8.54 ng mL(-1) (2-hydroxynaphthalene). The new method was found to be free of interference from four pharmacological drugs - naproxen, ibuprofen, diclofenac and amoxicillin - that might be found in urine samples of unhealthy individuals. PMID:23086075
Gas chromatography with isotope dilution mass spectrometry (GC-MS) and enzyme-linked immunosorbent assay (ELISA) were used in regional National Water Quality Assessment studies of the herbicides, 2,4-D and dicamba, in river water across the United States. The GC-MS method involved solid-phaseextraction, derivatized with deutemted 2,4-D, and analysis by selected ion monitoring. The ELISA method was applied after preconcentration with solid-phaseextraction. The ELISA method was unreliable because of interference from humic substances that were also isolated by solid-phaseextraction. Therefore, GC-MS was used to analyzed 80 samples from river water from 14 basins. The frequency of detection of dicamba (28%) was higher than that for 2,4-D (16%). Concentrations were higher for dicamba than for 2,4-D, ranging from less than the detection limit (<0.05 ??g/L) to 3.77 ??g/L, in spite of 5 times more annual use of 2,4-D as compared to dicamba. These results suggest that 2,4-D degrades more rapidly in the environment than dicamba.
Due to the effects that sediment or soil matrices have on the bioavailability of compounds, it has been difficult to screen toxicity of solid-associated contaminants. The majority of microbial assays for testing toxicity of soils and sediments have been performed on water or solvent extracts. These procedures lead to a fractionation of the toxicity, which may underestimate or overestimate exposure routes and consequently potential adverse environmental effects. Recently, a solid-phase Microtox assay which eliminates the need for soil extracts and utilizes whole sediments or soils has been developed. This report describes a toxicity testing procedure using the inhibition of dehydrogenase enzyme activity of Bacillus cereus as test parameter. Studies with soil samples and a synthetic sediment spiked with organic contaminants and copper indicate the higher sensitivity of both solid-phase bioassays compared to water extract testing. A comparison of the results demonstrates that the B. cereus contact test is more sensitive for copper than the Photobacterium phosphoreum solid-phase test. PMID:8521786
A high-performance liquid chromatographic method using a solid-phase borate-complex extraction pretreatment was studied for the selective quantitation of polyhydroxyflavones in vegetables, red wine and human blood plasma. Homogenate, extract and intact samples were applied to phenylboric acid cartridges to retain polyhydroxyflavones on the solid-phase by forming the borate-complex, followed by elution of the retained analytes with an acidic solvent. Reversed-phase chromatography with diode array detection allowed the simultaneous separation of rutin, myricetin, fisetin, morin, quercetin and kaempferol without significant interference from other components, indicating high selectivity of the solid-phase borate-complex extraction. The absolute recoveries of quercetin, fisetin and rutin were superior to those of kaempferol, myricetin and morin, suggesting a difference in the complex formation efficiency between 1,2- and 1,3-diol structures. When using fisetin as an internal standard, polyhydroxyflavones were quantified in the concentration range 0.10-30.0 microg/ml. In replicate spiking experiments with standards, the mean relative recoveries ranged between 75.7 and 104.6%, and the intra-and inter-assay C.V.s ranged between 0.8 and 10.2% for onion, wine and plasma samples. The proposed method will be applicable to nutritional and pharmacokinetic experiments of polyhydroxyflavones. PMID:9892086
Full text of publication follows: Laboratory experiments, where parameters are sequentially varied, are essential for defining thermodynamic constants and revealing mechanistic behaviour for contaminants adsorbed or incorporated by a solidphase. They can also reveal retardation potential, through the distribution coefficient, Kd. However, the nearly unresolvable problem of scaling-up laboratory results to field conditions has plagued us for decades and field experiments with toxic or radioactive contaminants are simply impossible. An intermediate solution has been to crush rock of interest and make column studies, but results from such experiments are unrealistic. Crushing produces new, previously unreacted surfaces that are full of defects. These new surfaces and adhering rock dust increase reactivity, meaning such columns cannot truly represent natural rock. A recent study of nickel (Ni) behaviour in a fractured chalk aquifer has shown that large, undisturbed columns can provide mass transport information that is more akin to field scale conditions than laboratory results. A pit was dug 5 meters into a fractured chalk aquifer. A boring machine extracted several columns 50 cm in diameter and 50 cm long. The column ends were fitted with caps with tubes for injection and extraction of solutions and the whole was sealed inside a rubber membrane. The water-tight assembly was then mounted inside a steel cylinder equipped with a water-cooling system. Pressure was adjusted to mimic that felt in the aquifer and temperature was held at 8 deg. C, typical of groundwater in Denmark,. Solutions were injected from the bottom of the column, with fixed pump rates. An unreactive tracer, Br{sup -}, identified water behaviour while inlet Ni concentration, CO{sub 2}, pH and other parameters were varied. Breakthrough behaviour provided a retardation factor, mass balance, and hints at the identity of the controlling processes. Final injection of blue tracer allowed definition of the water channel pathways when the core was dissected after dismounting. Kd determined from the columns was very close to that found from a field injection experiment in the same aquifer and mass balance proved that considerable Ni was immobilised within the column, most likely by cation substitution in calcite. Similar experiments with an actinide would have the added advantage that radio-photographs made from column slices, would show exactly where the actinide had sorbed. (authors)
The effectiveness of four extraction methods (modified QuEChERS, matrix solid-phase dispersion (MSPD), solid-liquid extraction (SLE) and solid-phaseextraction (SPE) clean-up) were evaluated for simultaneous determination of 32 mycotoxins produced by the genus Fusarium, Claviceps, Aspergillus, Penicillium and Alternaria in barley by ultra high pressure liquid chromatography coupled to ultra-high resolution mass spectrometry (UHPLC-Orbitrap(®) MS). The efficiency and efficacy of extraction methods were evaluated and compared in number of extracted mycotoxins and obtained recoveries. From the one point of view, QuEChERS procedure was fast and easy, as well as it was able to successfully extract all selected mycotoxins. On the other hand, SLE method, MSPD and SPE clean-up method did not extract adequately all selected mycotoxins and recoveries were not suitable enough. Thereby, method employing QuEChERS extraction connected with UHPLC-Orbitrap(®) MS was developed to quantify 32 mycotoxins in barley within this study. Analytical method was validated and recoveries ranged from 72% to 101% for selected mycotoxins with only one exception nivalenol (NIV) and deoxynivalenol-3-glucoside (D3G), which were lower than 67%. Relative standard deviations (RSD) were lower than 17.4% for all target mycotoxins. The lowest calibration levels (LCLs) ranged from 1 to 100?g/kg. Validated method was finally used for monitoring mycotoxins in a total of 15 Czech barley samples, when only Fusarium toxins representatives were detected in 53% of samples and the mycotoxins with the highest incidence were enniatins. PMID:22967615
A method based on solid-phaseextraction with a molecularly imprinted polymer (MIP) has been developed to determine five probable human carcinogenic polycyclic aromatic hydrocarbons (PAHs) in ambient air dust by gas chromatography-mass spectrometry (GC-MS). Molecularly imprinted poly(vinylpyridine-co-ethylene glycol dimethacrylate) was chosen as solid-phaseextraction (SPE) material for PAHs. The conditions affecting extraction efficiency, for example surface properties, concentration of PAHs, and equilibration times were evaluated and optimized. Under optimum conditions, pre-concentration factors for MIP-SPE ranged between 80 and 93 for 10 mL ambient air dust leachate. PAHs recoveries from MIP-SPE after extraction from air dust were between 85% and 97% and calibration graphs of the PAHs showed a good linearity between 10 and 1000 ng L{sup -1} (r=0.99). The extraction efficiency of MIP for PAHs was compared with that of commercially available SPE materials - powdered activated carbon (PAC) and polystyrene-divinylbenzene resin (XAD) - and it was shown that the extraction capacity of the MIP was better than that of the other two SPE materials. Organic matter in air dust had no effect on MIP extraction, which produced a clean extract for GC-MS analysis. The detection limit of the method proposed in this article is 0.15 ng L{sup -1} for benzo[a]pyrene, which is a marker molecule of air pollution. The method has been applied to the determination of probable carcinogenic PAHs in air dust of industrial zones and satisfactory results were obtained. (orig.)
This paper reports the preparation of puerarin (PR) imprinted layer-coated silica microparticles toward selective recognition of PR and fast affinity-enrichment of the main isoflavonoid glycosides from the crude extract of Radix puerariae. Before the preparation, quantum mechanics (QM) method was applied to identify three kinds of common functional monomers capable of interaction with PR and then predicted optimal functional monomer (acrylamide, AA) and the relative molar ratio of template to functional monomer (PR/AA, 1:4). The obtained PR-imprinted silica microparticles were evaluated by transmission electron microscope (TEM) and rebinding experiments, exhibiting good morphology and high binding affinity to PR. Meanwhile, the rebinding amount of the imprinted microparticles to PR was nearly 2.1-folds that of non-imprinted microparticles. When the PR-imprinted microspheres were used as packing materials for solid-phaseextraction, the recovery yields of PR, daidzin (DD) and genistin (GS) were simultaneously up to 90% by one-step extraction from the crude extract of Radix puerariae. Additionally, the PR-imprinted microparticles could be re-used for at least 5 times without losing any extraction efficiency. These results indicate that the PR-imprinted microparticles have highly selective adsorption capabilities to PR, DD and GS from the crude extract of Radix puerariae. The method of molecularly imprinted polymers (MIPs) coupled with solid-phaseextraction (SPE) provides a good solution of the enrichment and separation of active extracts from complicated traditional Chinese medicine (TCM) with certain structures. PMID:22553769
In the present work, an analytical method for the simultaneous determination of seven non steroidal anti-inflammatory drugs (naproxen, ketoprofen, diclofenac, piroxicam, indomethacin, sulindac and diflunisal) and the anticonvulsant carbamazepine is reported. The method involves preconcentration and clean-up by solid-phase microextraction using polydimethylsiloxane/divinylbenzene fibers, followed by liquid chromatography with diode array detection analysis. Parameters that affect the efficiency of the solid-phase microextraction step such as soaking solvent, soaking period, desorption period, stirring rate, extraction time, sample pH, ionic strength, organic solvent and temperature were investigated using a Plackett-Burman screening design. Then, the factors presenting significant positive effects on the analytical response (soaking period, stirring rate, stirring time) were considered in a further central composite design to optimize the operational conditions for the solidphase microextraction procedure. Additionally, multiple response simultaneous optimization by using the desirability function was used to find the optimum experimental conditions for the on-line solid-phase microextraction of analytes in river water samples coupled to liquid chromatography and diode array detection. The best results were obtained using a soaking period of 5 min, stirring rate of 1400 rpm and stirring time of 44 min. The use of solid-phase microextraction technique avoided matrix effect and allowed to quantify the analytes in river water samples by using Milli-Q based calibration graphs. Recoveries ranging from 71.6% to 122.8% for all pharmaceuticals proved the accuracy of the proposed method in river water samples. Method detection limits were in the range of 0.5-3.0 microgL(-1) and limits of quantitation (LOQs) were between 1.0 and 4.0 microgL(-1) for pharmaceutical compounds in river water samples. The expanded uncertainty associated to the measurement of the concentration ranged between 8.5% and 29.0% for 20 microgL(-1) of each analyte and between 9.0% and 29.5% for the average of different concentration levels. The main source of uncertainty was the calibration step in both cases. PMID:18950779
Stir bar sorptive extraction (SBSE) was introduced in 1999 as a solventless sample preparation method for the extraction and enrichment of organic compounds from aqueous matrices. The method is based on sorptive extraction, whereby the solutes are extracted into a polymer coating on a magnetic stirring rod. The extraction is controlled by the partitioning coefficient of the solutes between the polymer coating and the sample matrix and by the phase ratio between the polymer coating and the sample volume. For a polydimethylsiloxane coating and aqueous samples, this partitioning coefficient resembles the octanol-water partitioning coefficient. In comparison to solidphase micro-extraction, a larger amount of sorptive extraction phase is used and consequently extremely high sensitivities can b...
Pisum sativum is of great economic and nutritional interest due to its protein content. Nevertheless, pea products are underused as a protein source in human food because of their strong beany flavour. Therefore, the objective of this study was to select an efficient and representative method to extract volatile molecules of pea flour. In the first step, three extraction methods were chosen: solidphase micro extraction (SPME); Purge and Trap extraction and solvent assisted flavour evaporation (SAFE). The corresponding extracts were analysed by gas chromatography coupled with mass spectrometry. In the second step, the sensory representativity of the extracts was assessed either by direct gas chromatography-olfactometry for SPME and for Purge and Trap extracts, or by sniffing for the aqueou...
An analytical chemical method has been developed for the simultaneous determination of 32 different pharmaceuticals in soils and sediments. The pharmaceuticals cover a varity of different compound groups. Soil samples were extracted with different solvents with the help of pressurized-liquid extraction (PLE) followed by clean-up using a solid-phaseextraction (SPE) procedure. The purified extracts were analyzed by LC-MS/MS. The extraction method was evaluated by testing the following variables: extraction solvents, solvent pH, and temperature. Applying 20?g of soil/sediment and extracting with a mixture of methanol with aqueous ammonia solution (0.1?mol?L?1) at 80??C for 5?min in five cycles provided satisfactory recoveries between 66 and 114% with SD of between 1 and 14%. For preconcentra...
Abstract in portuguese No presente trabalho uma metodologia analítica é descrita para determinar a presença de multi-residuos de pesticidas utilizados na cultura da cana de açúcar (tebuthiuron, hexazinona, diuron, 2,4-D e ametrina), em fontes de água de abastecimento. Os analitos foram isolados da matriz água, através das seguintes técnicas: extração liquido-liquido (LLE), utilizando diclorometano como solvente; extração em fase sólida (SPE), utilizando C18 como suporte sólido e (more) acetonitrila como solvente para condicionamento da fase e eluição dos analitos; e extração com fluido supercrítico (SFE), utilizando C18 como suporte sólido e CO2 no estado supercrítico como solvente de extração. Análise cromatográfica foi feita por cromatografia liquida de alta eficiência (HPLC) com detector ultravioleta, utilizando acetonitrila/água como fase móvel. Dentre as três técnicas de extração avaliadas, os melhores resultados foram obtidos com extração liquido-liquido e extração em fase sólida. Abstract in english In the present work an analytical methodology is described to determine the presence of multi-residues of selected pesticides used in sugar-cane cultures (tebuthiuron, hexazinone, diuron, 2,4-D and ametrine), in source of drinking water. The analytes were isolated from the water matrix through the following techniques: liquid-liquid extraction (LLE) using dichloromethane as solvent; solidphaseextraction (SPE) using C18 as solid support and acetonitrile as solvent to con (more) dition the solidphase and elution of the analytes; and supercritical fluid extraction (SFE) using C18 as solid support and CO2 in supercritical state as extractant solvent. The chromatographic analysis was done by high performance liquid chromatography (HPLC) with an ultraviolet detector and using acetonitrile/water as mobile phase. Among the three evaluated extraction techniques, the best results were obtained with both liquid-liquid extraction and solidphaseextraction.
A number of extraction methods have been developed to assess polycyclic aromatic hydrocarbon (PAH) bioavailability in soils. As these methods are rarely tested in a comparative manner, against different test organisms, and using field-contaminated soils, it is unclear which method gives the most accurate measure of the actual soil ecosystem exposure. In this study, PAH bioavailability was assessed in ten field-contaminated soils by using exhaustive acetone/hexane extractions, mild solvent (butanol) extractions, cyclodextrin extractions, and two passive sampling methods; solidphase micro extraction (SPME) and polyoxymethylene solidphaseextraction (POM-SPE). Results were compared to actual PAH bioaccumulation in earthworms (Eisenia fetida) and rye grass (Lolium multiflorum) roots. Exhaustive, mild solvent and cyclodextrin extractions consistently overpredicted biotic concentrations by a factor of 10-10?000 and therefore seem inappropriate for predicting PAH bioaccumulation in field contaminated soils. In contrast, passive samplers generally predicted PAH concentrations in earthworms within a factor of 10, although correlations between predicted and measured concentrations were considerably scattered. The same applied to the plant data, where passive samplers also tended to underpredict root concentrations. These results indicate the potential of passive samplers to predict PAH bioaccumulation, yet call for comparative studies between passive samplers and further research on plant bioavailability. PMID:22191550
For the research on the extraction of uranium from seawater, various processes have been examined, but the most promising process is adsorption. Its key point is the performance of the adsorbent. The system as compact as possible, in which a large quantity of seawater effectively contacts with the adsorbent, must be constructed economically. As the inorganic adsorbent, titanium oxide is the best, but organic amidoxime is superior to it. The present state of the development of the adsorbent, the rate of adsorption of the adsorbenbt, the seawater uranium adsorption system and the experiment in Imari Bay are reported. (K.I.).
ZrO2 nanoparticle dispersions containing associative polymers exhibit two relaxation modes: Maxwellian behavior at high frequency imparted by the associating polymers and a power law spectrum at low frequency generated by the particle dynamics. The timescales and volume fraction dependence of the dispersions reflect weak attractions between particles with adsorbed polymer layers dispersed in a percolated network of associative polymer. The Baxter stickiness parameter extracted from the high frequency viscosity data indicates strong attractions, whereas the high frequency modulus reveals three sources of elasticity: micelle?micelle associations in the solution, rigidity of the particles and adsorbed layer, and adsorbed layer?adsorbed layer interactions. The sol-gel transition of the dispers...
Fluorometric determination of thiamine requires the conversion of the analyte to fluorescent thiochrome by hexacyanoferrate(III) oxidation in alkaline solution and the isolation of the produced thiochrome from the reaction medium by solvent extraction. It was observed that thiochrome could be concentrated and separated from the reaction medium by solid-phaseextraction. The thiochrome sorpted on the surface of octadecyl-alkylated poly-[styrene/divinylbenzene] (C18-PS/DP) microbeads emitted strong fluorescence upon excitation, the maximum excitation and emission wavelengths being 385 nm and 433 nm, respectively. Based on this observation, a sequential injection renewable surface solid-phase spectrofluorometry was developed for the determination of thiamine. A sequential injection system on-line coupled to a chip-based flow-through cell was employed to handle the chemical reaction, bead injection and discharging, and adsorption of thiochrome. Solid-phase fluorometric detection was realized by coupling the chip-based flow-through cell to a spectrofluorometer with a multistrand bifurcated optical fiber. Under the optimized condition, a detection limit of 0.03 ?g ml-1 was achieved at the sample throughput of 30 h-1 and consumption of 1 mg C18-PS/DP microbeads for each run. Eleven runs of a 2 ?g ml-1 thiamine standard solution gave a relative standard deviation of 1.0%. The developed approach was successfully applied for the determination of thiamine contents in pharmaceutical preparations.
A sensitive and simple immunoassay to determine 17?-estradiol (E2) in fresh water was developed. The method is based on a solid-phase avidin-biotin binding assay and solidphaseextraction. The binding event of E2 to the antibody is detected indirectly by the competitive reaction between E2 and biotinylated estradiol (BE) as a tracer for the limited binding sites of antibodies immobilized onto the wall of a microtiter plate. Namely, E2 concentrations are determined from the strong interaction between BE and avidin conjugated with horseradish peroxidase (avidin-HRP). In order to achieve a sensitive measurement for the binding of BE to the antibody immobilized on the microtiter plate substrate, QuantaBlu™ fluorogenic peroxidase substrate (QFPS) was employed. The detection limit and the linear range of E2 determination were 27 pM and 27 - 7480 pM, respectively. The relative standard deviations (RSD) for the E2 assay were between 0.3 and 12.0% (n = 3). The cross-reactivities of several other estrogens in this assay system were also investigated. No serious influences from any cross-reaction caused by other estrogens tested in this experiment were observed. The determination of E2 in water samples from eight rivers and a marsh in Hokkaido was performed by the immunoassay combined with solidphaseextraction. It was found that the concentration of E2 was in the range between 0.06 and 67 pM.
A highly sensitive spectrophotometric determination of cationic surfactants in ground waters was established by forming their Cu(II)-TPPS aggregates, preceded by solid-phaseextraction with an SCX cartridge. Cationic surfactants (CSs) were quantitatively trapped and isolated by the SCX solidphase. The use of Cu(II)-TPPS anionic chromophore could reduce the interference by unintentional metal ions coexisting in surrounding waters. The method was very sensitive in the determination of CSs less than 10-5M levels with acceptable recovery and calibration data. The colorimetric sensitivity was very dependent on the alkyl-chain length of the surfactants, and a CS having 23 carbon atoms gave the highest sensitivity. Overall recoveries were 95-97% with R.S.Ds. less than 3% in the cases over 10-6M ...
In this study, a comprehensive evaluation of two simple sample treatment methodologies has been carried out for the development of large-scale multi-residue methods for pesticide testing in olive oil. The proposed methodologies are based on (a) liquid-liquid partitioning with acetonitrile followed by dispersive solid-phaseextraction clean-up using graphitized carbon black, primary-secondary amine and C18 sorbents; (b) liquid partitioning with acetonitrile saturated with petroleum ether followed by matrix solid-phase dispersion (MSPD) using aminopropyl as sorbent material and a Florisil cartridge for final clean-up in the elution step. To evaluate the proposed sample treatment methodologies, 105 representative multi-class pesticides were studied using fast liquid chromatography-electrospra...
We describe the construction of a multi-phase equation of state for carbon at extreme pressures based on ab initio electronic structure calculations of two solidphases (diamond and BC8) and the liquid. Solid-phase free energies are built from knowledge of the cold curves and phonon calculations, together with direct ab initio molecular dynamics calculations of the equation of state, which are used to extract anharmonic corrections to the phonon free energy. The liquid free energy is constructed based on results from molecular dynamics calculations and constraints determined from previously calculated melting curves, assuming a simple solid-like free energy model. The resulting equation of state is extended to extreme densities and temperatures with a Thomas Fermi-based free energy model. Comparisons to available experimental results are discussed.
A separation/preconcentration procedure using solidphaseextraction coupled to zinc vapor generation associated to inductively coupled plasma optical emission spectrometry determination in water samples was studied. The solidphase material was ethyl vinyl acetate (EVA) contained in a column, where the analyte ions were retained without using any complexation agent. The variables involving the preconcentration and the chemical vapor generation (CVG) were optimized using both full factorial and central composite designs, respectively. Volatile species of zinc were generated by merging the acidified eluent and sodium tetrahydroborate in a continuous flow system. The gaseous analyte was introduced via a stream of Ar carrier into the inlet tube of the ICP torch. An enhancement factor of 230-f...
Alkylphosphonic acids (APAs) are degradation products and chemical markers of organophosphorous (OP) nerve agents (chemical warfare agents). Anion exchange disk-based solidphaseextraction (SPE) has been combined with in vial solidphase derivatization (SPD) and GC-MS analysis for the determination of APAs in aqueous samples. The optimization of critical method parameters, such as the SPD reaction, was achieved using statistical experimental design and multivariate data analysis. The optimized method achieved quantitative recoveries in the range from 83% to 101% (n=13, RSD from 4% to 10%). The method was sensitive, with LODs in SIM mode of 0.14ppb, and demonstrated excellent linearity with an average R^2>=0.99 over the concentration range of 0.07-1.4ppm in full scan mode and from 0.14ppb ...
Reversible covalent chemistry (RCC) adds another dimension to commonly used sample preparation techniques like solid-phaseextraction (SPE), solid-phase microextraction (SPME), molecular imprinted polymers (MIPs) or immuno-affinity cleanup (IAC): chemical selectivity. By selecting analytes according to their covalent reactivity, sample complexity can be reduced significantly, resulting in enhanced analytical performance for low-abundance target analytes. This review gives a comprehensive overview of the applications of RCC in analytical sample preparation. The major reactions covered include reversible boronic ester formation, thiol-disulfide exchange and reversible hydrazone formation, targeting analyte groups like diols (sugars, glycoproteins and glycopeptides, catechols), thiols (cysteinyl-proteins and cysteinyl-peptides) and carbonyls (carbonylated proteins, mycotoxins). Their applications range from low abundance proteomics to reversible protein/peptide labelling to antibody chromatography to quantitative and qualitative food analysis. In discussing the potential of RCC, a special focus is on the conditions and restrictions of the utilized reaction chemistry. PMID:23013801
A simple, fast, and sensitive method for determination of 17 ?-estradiol (E2) in goat milk samples has been developed by combining selective molecularly imprinted matrix solid-phase dispersion (MIP?MSPD) and liquid chromatography with diode-array detection (DAD). The molecularly imprinted polymer was synthesized by use of 17?-estradiol as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker monomer, azobisisobutyronitrile as initiator, and acetonitrile as porogen, and was used as selective solid support for matrix solid-phase dispersion. The selected dispersant had high affinity for E2 in the goat milk matrix and the extract obtained was sufficiently clean for direct injection for HPLC analysis without any interferences from the matrix. T...
Iron compounds in soil are multifunctional, providing physical structure, ion sorption sites, catalytic reaction-centers, and a sink for respiratory electrons. Basaltic soils contain large quantities of iron that reside in different mineral and organic phases depending on their age and redox status. We investigated changes in soil iron concentration and its solid-phase speciation across a single-aged (400ky) lava flow subjected to a gradient in precipitation (2200-4200mmyr-1) and hence redox history. With increasing rainfall and decreasing Eh, total Fe decreased from about 25% to <1% of the soil mass. Quantitative speciation of soil solid-phase iron was constrained by combining 57Fe Mossbauer spectroscopy (MBS) at 295 and 4.2K with powder X-ray diffraction, selective chemical extractions, ...
The matrix solid-phase dispersion (MSPD) technique accompanied with LC-MS/MS detection for the purpose of determination of 12 pharmaceuticals (sulfaguanidine, sulfadiazine, sulfamethazine, sulfamethoxazole, trimethoprim, roxithromycin, praziquantel, febantel, enrofloxacin, ciprofloxacin, norfloxacin and procaine) applied to sediment samples has been described in this paper. Different parameters, such as the type of solidphase, the elution solvent and its volume have been investigated. The analytes were successfully extracted by C18 as an MSPD sorbent with 5mL of acetonitrile:5% of oxalic acid=6:4 (v/v) as an elution solvent. The proposed method provides a linear response over the concentration range of 0.0005-100mg/g, depending on pharmaceuticals with correlation coefficients above 0.9928...
In this study, a new solidphase extractor, nano-scale silver particles were synthesized. The silver nanoparticle-based solidphaseextraction was used for separation and preconcentration of the trace amount of cobalt ion from various water samples prior to its determination by flame atomic absorption spectrometry. The effects of various parameters, including pH, amount of complexing agent [1-(2-pyridylazo)-2-naphthol] (PAN), flow rates of solution and eluent, type and least amount of the eluent for elution of the cobalt from silver nanoparticles were studied and optimized. Under the optimum conditions, the detection limit of this procedure was 0.78 ?g L-1, and the relative standard deviation (RSD%) was 3.1% ( n = 10, c = 20 ?g L-1). This method was applied to the determination of cobalt in water samples.
A solid-phase chemiluminescent immunoassay (LIA) for the determination of cortisol in serum specimens has been developed. The separation of the cortisol onto the solid-phase distinguishes this particular assay from other chemiluminescence immunoassays. The method can be used without prior extraction. Cortisol molecules were made chemiluminescent by conjugation to aminobutylethyl-isoluminol. The detection limit of the label in the chemiluminescent reaction was 0.1 pmol. The LIA was compared with a RIA for cortisol in 36 serum specimens and the correlation between the assays was good (r = 0.97). The time course of the chemiluminescent reaction is fast and a 20's integration time gave reproducible results. The peak light intensities were not reliable. PMID:7087482
A miniaturized method based on matrix solid-phase dispersion coupled to solidphaseextraction and high performance liquid chromatography with diode array detection (MSPD-SPE-HPLC/DAD) was developed for the trace simultaneous determination of the following organophosphorus pesticides (OPPs) in bovine tissue: parathion-methyl, fenitrothion, parathion, chlorfenvinphos, diazinon, ethion, fenchlorphos, chlorpyrifos and carbophenothion. To perform the coupling between MSPD and SPE, 0.05g of sample was dispersed with 0.2g of C18 silica sorbent and packed into a stainless steel cartridge containing 0.05g of silica gel in the bottom. After a clean-up of high and medium polarity interferences with water and an acetonitrile:water mixture, the OPPs were desorbed from the MSPD cartridge with pure acet...
Recycling of enzymes during biomass conversion is one potential strategy to reduce the cost of the hydrolysis step of cellulosic ethanol production. Devising an efficient enzyme recycling strategy requires a good understanding of how the enzymes adsorb, distribute, and interact with the substrate during hydrolysis. We investigated the interaction of individual Trichoderma reesei enzymes present in a commercial cellulase mixture during the hydrolysis of steam-pretreated corn stover (SPCS). The enzyme profiles were followed using zymograms, gel electrophoresis, enzyme activity assays and mass spectrometry. The adsorption and activity profiles of 6 specific enzymes Cel7A (CBH I), Cel7B (EG I), Cel5A (EG II), Xyn 10 (endo-1,4-?-xylanase III), Xyn 11 (endo-xylanase II), and ?-glucosidase were characterized. Initially, each of the enzymes rapidly adsorbed onto the SPCS. However, this was followed by partial desorption to an adsorption equilibrium where the Cel7A, Cel7B, Xyn 10, and ?-glucosidase were partially adsorbed to the SPCS and also found free in solution throughout the course of hydrolysis. In contrast, the Cel5A and Xyn 11 components remained primarily free in the supernatant. The Cel7A component also exhibited a partial desorption when the rate of hydrolysis leveled off as evidenced by MUC zymogram and SDS-PAGE. Those cellulase components that did not bind to the substrate were generally less stable and lost their activities within the first 24h when compared to enzymes that were distributed in both the liquid and solidphases. Therefore, to ensure maximum enzyme activity recovery, enzyme recycling seems to be most effective when short-term rounds of hydrolysis are combined with the recovery of enzymes from both the liquid and the solidphases and potentially enzyme supplementation to replenish lost activity. PMID:22305175
A new sol-gel hybrid coating, polydimethylsiloxane-2-hydroxymethyl-18-crown-6 (PDMS-2OHMe18C6) was prepared in-house for use in solidphase microextraction (SPME). The three compositions produced were assessed for its extraction efficiency towards three selected organophosphorus pesticides (OPPs) based on peak area extracted obtained from gas chromatography with electron capture detection. All three compositions showed superior extraction efficiencies compared to commercial 100mm PDMS fiber. The composition showing best extraction performance was used to obtain optimized SPME conditions: 75^oC extraction temperature, 10min extraction time, 120rpm stirring rate, desorption time 5min, desorption temperature 250^oC and 1.5% (w/v) of NaCl salt addition. The method detection limits (S/N=3) of t...
In this study on the production of novel varietal hop aromas by supercritical fluid extraction of hop pellets we aim at fractionated extraction of hop oil essences by density programmed supercritical fluid extraction (SFE) of hop pellets T90 using carbon dioxide. For that purpose, SFE is performed in two steps. In the first step, the most volatile compounds from hop essential oil are isolated by extracting pellets T90 applying a carbon dioxide density of 0.29g/mL (90atm, 50^oC). Subsequent fractionation of the crude extract from this first SFE step via solidphaseextraction (SPE) using octadecylsilica and ethanol/water mixtures, results in flavour-active single variety hop oil essence, highly enriched in 'floral' compounds of total hop essential oil. When added to a non-aromatised pilot l...
This paper reports on the development and optimization of a modified Quick, Easy, Cheap Effective, Rugged and Safe (QuEChERS) based extraction technique coupled with a clean-up dispersive-solidphaseextraction (dSPE) as a new, reliable and powerful strategy to enhance the extraction efficiency of free low molecular-weight polyphenols in selected species of dietary vegetables. The process involves two simple steps. First, the homogenized samples are extracted and partitioned using an organic solvent and salt solution. Then, the supernatant is further extracted and cleaned using a dSPE technique. Final clear extracts of vegetables were concentrated under vacuum to near dryness and taken up into initial mobile phase (0.1% formic acid and 20% methanol). The separation and quantification of fr...
Abstract in english The analysis of drugs and metabolites in biological fluids usually requires extraction procedures to achieve sample clean-up and analyte preconcentration. Commonly, extraction procedures are performed using liquid-liquid extraction or solid-phaseextraction. Nevertheless, these extraction techniques are considered to be time-consuming and require a large amount of organic solvents. On this basis, microextraction techniques have been developed. Among them, liquid-phase mic (more) roextraction has been standing out. This review describes the liquid-phase microextraction technique based on hollow fibers as a novel and promising alternative in sample preparation prior to chromatographic or electrophoretic analysis. The basic concepts related to this technique and its applicability in extraction of drugs are discussed.
The paper presents the development of a multiple consecutive extraction method enabling the determination of the total amount of bisphenol A (BPA) released from porous polysulfone (PS) membranes in a hemodialyzer or hemoconcentrator under simulated-use conditions. The levels of BPA were determined using solidphaseextraction (SPE) coupled with high performance liquid chromatography–mass spectrometry (HPLC–MS). We demonstrated that it was difficult to determine the total amount of BPA released from the PS membranes using a single extraction method with finite solvent volume because of the chemical equilibrium between the extraction solution and the polymer phase. Repeated extractions gave more accurate results than a single extraction for the determination of the total amou...
Rosmarinus officinalis (rosemary) extracts were obtained in a supercritical pilot-scale plant. Based on experimental information available in the literature for analytical or low-scale processes, extraction temperature and pressure were selected to be 313K and 30MPa. At these extraction conditions, the kinetic behavior of the pilot-scale overall extraction curve were determined with respect to yield, antioxidant activity and carnosic acid content. The overall extraction curve was represented using Sovova's model; the average deviation between measured and calculated yields was lower than 2%. Mass transfer coefficients in the fluid and solidphases were determined and were compared with previous data reported in the literature for low-scale rosemary supercritical extraction. A two-stage dep...
Abstract In this study, silica-coated magnetic nanoparticles (Fe3O4/SiO2 NPs) modified by cetyltrimethylammonium bromide (CTAB) were synthesized. They were successfully applied for extraction of xanthohumol in beer based on magnetic mixed hemimicelles solid-phaseextraction (MMHSPE) coupled with high-performance liquid chromatography - ultraviolet determination. The main factors influencing the extraction efficiency including the surfactant amount, the beer pH, the extraction time, the desorption condition and the maximum extraction beer volume were optimized. Under the optimized conditions, a concentration factor of 60 was achieved by extracting 120-mL beer sample using MMHSPE and the detection limit of xanthohumol is 0.0006-mg/L. The proposed method was successfully applied for determina...
An efficient and reliable method based on gas chromatography?mass spectrometry (GC?MS) was developed for the extraction and analysis of six phenolic endocrine disrupting chemicals (EDCs), such as 4-nonylphenol (4-NP), nonylphenol-mono-ethoxylate (NP1EO), nonylphenol-di-ethoxylate (NP2EO), 4-tert-octylphenol (4-t-OP), bisphenol A (BPA) and 4-cumylphenol (4-CP) in surface water and sediment. The method was developed by using microwave-assisted extraction (MAE), solidphaseextraction (SPE) and derivatization procedure. The MAE procedures were performed by optimizing three key process factors, consisted of extraction solvent, extraction temperature and holding time, affecting the extraction efficiency from sediment samples. For SPE, various parameters that may affect the recovery efficiency o...
An ultrasound assisted microwave extraction (UAME) method was developed to simultaneously extract five organophosphate (OP) and eight pyrethroid insecticides from sediment. The optimized UAME conditions were to use 100ml of a mixture of hexane and acetone (1:1, v/v) solution as the extraction solvents, and extraction time, microwave and ultrasonic power settings of 6min, 100W and 50W, respectively. Extracts were cleaned using solidphaseextraction and analyzed by gas chromatography-mass spectrometry in negative chemical ionization mode and quantification was based on matrix-matched standard solutions along with internal standard calibration. At the spiked concentrations of 1, 5 and 20ng/g dry weight (dw), recoveries of OPs were 77.6-122%, 65.2-128% and 75.6-141% with relative standard dev...
In this study seven published methods of extraction of skin free and bound volatile compounds have been compared. The free and bound volatiles were separated by solidphaseextraction (SPE) and then analysed by gas chromatography coupled with mass spectrometry (GC-MS). The results showed that the extraction of volatile compounds from grapes is highly affected by extraction solution features. The solution at pH 3.2 and 0% ethanol resulted the most effective as it led to the extraction of a higher number and amount of free and glycosilated volatile compounds. The selected extraction method of grape skin and the process of pulp juice were validated for quantitative determination of a wide range of grape aroma compounds. A total of 37 free and bound grape aroma compounds were quantified by GC-MS in selective ion monitoring modality (SIM). Among them, 26 volatile compounds resulted validated in grape skin and pulp juice. PMID:23122133
