Water-compatible poly (hydroxyethyl methacrylate) polymer sorbent for miniaturized syringe assisted extraction of sulfonamides in milk

A simple, convenient, and economic self-assembly miniaturized syringe assisted extraction (mini-SAE) using poly (hydroxyethyl methacrylate) polymer (PHEMA) as sorbent coupled with liquid chromatography was proposed for rapid screening of sulfadiazine (SD) and sulfamonomethoxine (SMM) in milk. The water-compatible PHEMA was synthesized by reversible addition-fragmentation chain transfer precipitation polymerization using trithiocarbonate as chain transfer agent and methanol–water system as reaction medium. The obtained PHEMA sorbent showed good affinity to sulfonamides and was successfully applied as a special sorbent for a mini-SAE device for simultaneous extraction and isolation of SD and SMM in milk samples. Under the optimum condition, good linearity was obtained in a range of 7.0–700 ng g⁻¹ (r ≥ 0.9995) and the average recoveries of SD and SMM at three spiked levels were ranged from 85.6 to 100.3% with the relative standard deviations (RSD) ≤6.5%. The presented PHEMA-mini-SAE protocol could be potentially applied as an alternative tool for analyzing the residues of SAs in complicated biological samples.     

Molybdenum-Blue Spectrophotometric Method for Determination of Lewisite Vapor in Air

Abstract

A method was developed for determining lewisite vapor in air. The method entails the collection of lewisite in an impinger or solid-sorbent sampler, conversion of the trapped lewisite to arsenite ion, oxidation of arsenite to arsenate, and determination of the arsenate ion by molybdenum-blue spectrophotometry. Relative to other available techniques, the one described here requires a minimum of instrumentation and can be executed without the use of highly toxic lewisite solutions for instrument calibration.     

Desulfurization kinetics of ZnO sorbent loaded on semi-coke support for hot coal gas

Zn-based sorbent (Z20SC) prepared through semi-coke support in 20 wt% zinc nitrate solution by high-pressure impregnation presents an excellent desulfurization capacity in hot coal gas,in which H2 S can not be nearly detected in the outlet gas before 20 h breakthrough time.The effects of the main operational conditions and the particle size of Z20SC sorbent on its desulfurization performances sorbent were investigated in a fixed-bed reactor and the desulfurization kinetics of Z20SC sorbent removing H2 S from hot coal gas was calculated based on experimental data.Results showed that the conversion of Z20SC sorbent desulfurization reaction increased with the decrease of the particle size of the sorbent and the increases of gas volumetric flow rate,reaction temperature and H 2 S content in inlet gas.Z20SC sorbent obtained from hydrothermal synthesis by high-pressure impregnation possessed much larger surface area and pore volume than semi-coke support,and they were significantly reduced after the desulfurization reaction.The equivalent grain model was reasonably used to analyze experimental data,in which k s=4.382×10-3 exp(-8.270×103/RgT) and Dep=1.262×10-4exp(1.522×104/RgT).It suggests that the desulfurization reaction of the Z20SC sorbent is mainly controlled by the chemical reaction in the initial stage and later by the diffusion through the reacted sorbent layer.     

On‐Line Selective Solid‐Phase Extraction of Copper with a Surface Ion Imprinted Silica Gel Sorbent

Copper(II)‐ion imprinted silica gel (Cu‐IISG) sorbent was synthesized by surface imprinting technique and was employed as a selective solid‐phase extraction material for on‐line preconcentration and separation, then coupled with atomic absorption spectrometry (AAS) determination of Cu(II). The higher selectivity coefficient of Cu‐IISG for Cu(II) in the presence of competitive ions such as Fe(III), Ni(II) and Zn(II) was above 411, which was 35 times of NISG. The static adsorption capacity and dynamic adsorption capacity were 41.11 mg g^?1 and 16.20 mg g^?1, respectively. The Cu‐IISG offered a fast kinetics for the adsorption and desorption of Cu(II), which can be used for on‐line preconcentration and detection. Two certified reference materials of GBW07301a sediment and GBW07401 soil were analyzed and the determined values were in a good agreement with the certified values. The developed method was also successfully applied to the determination of trace copper in tea leaf with satisfactory results (recovery between 96.3% and 102.3%).     

Two new techniques for sample preparation in bioanalysis: Microextraction in packed sorbent (MEPS) and use of a bonded monolith as sorbent for sample preparation in polypropylene tips for 96-well plates

Analytical methods providing high throughput are required for the ever increasing number of samples in bioanalysis. Currently, the method of choice in bioanalysis is LC-MS-MS. This method is quite rapid and thereby the focus has been directed to sample preparation as being a bottleneck in total analysis systems. It has become necessary to develop sample preparation techniques to a new improved level. This development has been based on a systematic and scientific approach. The key factors in this development have been miniaturization, integration, and automation of the techniques. This review provides a short overview of recent developments. Special emphasis is on two techniques: microextraction in packed syringe (MEPS) and use of a monolithic acrylamide plug as sorbent in polypropylene tips primarily intended for use with 96-well plate systems.     

工作场所空气中54种挥发性烃类物质的检测

采用Tenax-TA吸附剂管采集工作场所空气中54种挥发性烃类化合物,经热脱附-气相色谱检测。结果显示,1,1-二氯乙烯、二氯甲烷、1,2-二氯乙烯(反式)、1,2-二氯乙烯(顺式)、2,2-二氯丙烷、溴氯甲烷、1,1,1-三氯乙烷、1,2-二氯乙烷、1,1-二氯丙烯的相关系数在0.9941～0.9986之间,溴氯甲烷、二溴甲烷、三氯甲烷、溴二氯甲烷、2,2-二氯丙烷、二溴氯甲烷、溴仿的检出限为5.4～10.3ng,最低检出浓度0.01～0.1mg/m3(采样体积0.5L)。其余38种挥发性烃类物质的相关系数均大于0.999,最低检出浓度0.001～0.01mg/m3;其中烯烃类检出限为0.4～2.7ng、烷烃类为1.4～3.7ng、芳香烃类为0.2～1.0ng、萘为2.2ng;54种挥发性烃类物质的热脱附效率92.1%～113.1%,RSD为0.6%～17.4%,除1,2-二氯乙烯(顺式)、1,1-二氯乙烷、1,1,1-三氯乙烷、1,1-二氯乙烯、2,2-二氯丙烷、三氯甲烷、1,2-二氯乙烯(反式)、二氯甲烷、溴氯甲烷的RSD值在5.1%～17.4%外,其余45种挥发性烃类物质的RSD均小于5%;9种化合物...     

Hypercrosslinked strong anion‐exchange resin for extraction of acidic pharmaceuticals from environmental water

Two novel high‐specific surface area polymeric sorbents (HXLPP‐SAXa and HXLPP‐SAXb) were synthesised and evaluated as solid‐phase extraction sorbents. The novel sorbents under study are based on hypercrosslinked polymer microspheres and designed specifically to offer ion‐exchange properties; the specific polymers of interest in the current work have been chemically modified in such a way as to impart a tuneable level of strong anion‐exchange character onto the sorbents. The novel sorbents were applied as strong anion‐exchange sorbents in solid‐phase extraction studies, with the goal being to selectively extract a group of acidic compounds from complex environmental samples in an efficient manner. Out of two HXLPP‐SAX resins evaluated in this study, it was found that the sorbent with the lower ion‐exchange capacity (HXLPP‐SAXa) gave rise to the best overall performance characteristics and, indeed, was found to compare favourably to the solid‐phase extraction performance of commercial strong anion‐exchange sorbents. When the HXLPP‐SAXa sorbent was applied to the solid‐phase extraction of environmental water samples, the result showed quantitative and selective extraction of low levels of acidic pharmaceuticals from 500 mL of river water and 100 mL of effluent wastewater.     

The effect of structural parameters of biporous packing with an impermeable core on the gas separation efficiency

The effect of the structural parameters of granules of biporous sorbent with an adsorbing surface layer and inert core on the gas separation efficiency has been studied. The adsorbent has some advantages over sorbents with the bulk volume accessible for an adsorbate. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1193–1195, June, 1999.     

Aminopropyl-silica as an advantageous alternative to nonpolar sorbents for continuous cleanup/preconcentration of vitamin D3 metabolites

Summary A new procedure for continuous cleanup and concentration of hydroxyvitamin D₃ metabolites prior to their separation by HPLC and UV-detection is reported. The process is based on the use of aminopropyl-silica as solid-phase sorbent as an alternative to the use of nonpolar sorbents. The improvement thus achieved has been tested by comparing the results with those obtained using octadecyl-C₁₈ as non-polar sorbent. The comparison has been based on the calibration graphs (linear range, detection and quantitation limits), precision and multiple standard addition method.     

Rapid and sensitive methodology for determination of ethyl carbamate in fortified wines using microextraction by packed sorbent and gas chromatography with mass spectrometric detection

This work presents a new methodology to quantify ethyl carbamate (EC) in fortified wines. The presented approach combines the microextraction by packed sorbent (MEPS), using a hand-held automated analytical syringe, with one-dimensional gas chromatography coupled with mass spectrometry detection (GC–MS). The performance of different MEPS sorbent materials was tested, namely SIL, C2, C8, C18, and M1. Also, several extraction solvents and the matrix effect were evaluated. Experimental data showed that C8 and dichloromethane were the best sorbent/solvent pair to extract EC. Concerning solvent and sample volumes optimization used in MEPS extraction an experimental design (DoE) was carried out. The best extraction yield was achieved passing 300 μL of sample and 100 μL of dichloromethane. The method validation was performed using a matrix-matched calibration using both sweet and dry fortified wines, to minimize the matrix effect. The proposed methodology presented good linearity (R² = 0.9999) and high sensitivity, with quite low limits of detection (LOD) and quantification (LOQ), 1.5 μg L⁻¹ and 4.5 μg L⁻¹, respectively. The recoveries varied between 97% and 106%, while the method precision (repeatability and reproducibility) was lower than 7%. The applicability of the methodology was confirmed through the analysis of 16 fortified wines, with values ranging between 7.3 and 206 μg L⁻¹. All chromatograms showed good peak resolution, confirming its selectivity. The developed MEPS/GC–MS methodology arises as an important tool to quantify EC in fortified wines, combining efficiency and effectiveness, with simpler, faster and affordable analytical procedures that provide great sensitivity without using sophisticated and expensive equipment.