ADSORBENTS USED IN THE CLEARANCE OF ENDOTOXIN

1.INTRODUCTION[()-227.3()]Endotoxinislipopolysaccharide(LPS)derivedfromthecellmembranesofgram-negativebacteria.Endotoxincancausefebrilereactionsinanimalswithsymptomsofhighfever,vasodilation,diarrheaandfetalshockwheninjectedeveninaverysmallamount[1].Iftheconcentrationofendotoxininpatients?bloodishighenoughitcancauseseveresepsis,whichisamajorcauseofdeathinpatientsandcontinuestohaveahighmortalitydespiteappropriatesurgery,potentantibiotic,andintensivesupportivetherapy[2~5].LipidAisthemaintox…     

酚醛型吸附树脂对水体系中吡啶和N,N-二甲基苯胺的吸附性能研究

研究了酚醛型吸附树脂在水体系中对吡啶和N，N-二甲基苯胺的静态和动态吸附行为．结果表明，在水中树脂对吡啶和N，N-二甲基苯胺的吸附主要以疏水吸附机理进行；吸附吡啶和N．N-二甲基苯胺的初始阶段，即达到38．3～48．9％平衡吸附时，吸附速率数据和半经验速率方程很吻合：酚醛型吸附树脂等温吸附吡啶和N，N-二甲基苯胺的平衡吸附数据符合Langmuir方程，相关系数在0．99以上，酚醛型吸附树脂吸附吡啶和N，N-二甲基苯胺属单分子层吸附：用80％的乙醇溶液作洗脱剂来洗脱吸附吡啶已达饱和的JDW-2树脂，效果是很理想的．在3．6个床体积内洗脱率达91．52％，4．8个床体积内洗脱率达到94．85％。表明酚醛型吸附树脂具有优良的洗脱性能．     

固相微萃取/GC直接测定废水中的三种氯酚

研究了运用固相微萃取／GC直接测定水中的三种氯酚的方法，得到了分析三种氯酚的SPMF最佳萃取条件。选取聚丙烯酸酯（PA）萃取头，水溶液调pH=2,并用NaCl饱和，室温下在持续磁力搅拌下直接萃取40min，纤维萃取头在260℃脱附5min。所建立的方法适于快速、方便地测定水中三相氯酚，无须浓缩和预处理。     

New PVC materials for medical applications—the release profile of PVC/polycaprolactone–polycarbonate aged in aqueous environments

Medical grade PVC plasticised with polycaprolactone–polycarbonate (PCL–PC) was subjected to aqueous environments at different temperatures. The release profile during ageing was determined by solid phase microextraction (SPME) and GC–MS. At the same time changes in the surface composition due to, for example, migration of PCL–PC from the blend were followed by FTIR. Almost no changes in the material or its surface composition were observed during 98 days at 37 °C in water or phosphate buffer. Only trace amount of 6-hydroxyhexanoic acid the final hydrolysis product of PCL–PC was detected in the GC–MS chromatograms and the weight loss was negligible. Even when the ageing temperature was raised to 70 °C only minor increase in the amount of 6-hydroxyhexanoic acid was observed and the weight loss after 98 days was under 1%. Changes in the FTIR spectra indicating migration of PCL–PC towards the surface of the PVC/PCL–PC tubing were observed first after 70 days at 70 °C. Large increase in the hydrolysis rate of PCL–PC and almost complete depletion of PCL–PC from the blend was observed when the ageing temperature was raised to 100 °C.     

笼形聚偕胺肟树脂的研究──酸处理树脂吸附H_2PdCl_4

考查了无机酸、羧酸和酚类化合物处理的笼形聚偕胺肟树脂吸附酸性溶液中H_2PdCl_4的能力，其中H_3BO_3/ACAO、HSCH_2CO_2H/ACAO和p－NH_2C_6H_4H/ACAO树脂对H_2PdCl_4的吸附容量分别是2．023、2．368和2．083mmol/g-R或215、252和222mgPd／g－R。优于相同条件下的碱处理树脂（BCAO吸附容量为1．828mmol/g-R）。研究了吸附动力学，讨论了吸附机理。     

ADSORPTION OF 2,4-DICHLOROBENZOXYACETIC ACID ONTO HYPERCROSSLINKED RESIN MODIFIED BY PHENOLIC HYDROXYL GROUP (AM-1)

INTRODUCTIONAdsorption has been considered to be the best available technology for removing organics from water in the USSafe Drinking Water Act[1]. Due to many drawbacks of activated carbon[2-7], the most widely used adsorbent,hypercrosslinked polymeric adsorbents developed by Tsyurupa and Davankov[8] have been increasingly viewedas an alternative to activated carbon for selective removal of specific organic substances from contaminatedwater[9-12], and series of researches have been do…     

Solid-phase microextraction–capillary gas chromatography combined with microwave-induced plasma atomic-emission spectrometry for selenite determination

The use of solid-phase microextraction (SPME) with gas chromatography coupled to microwave-induced plasma atomic-emission detection (GC–MIP-AED) is described for selenite [Se(IV)] speciation. Aqueous standards were derivatised with sodium tetraethyl- or tetrapropylborate and extracted by SPME. Headspace extraction of the ethyl and propyl derivatives was studied. Relevant experimental conditions were optimised, including conditions for derivatisation and extraction and those of gas chromatographic analysis. The limits of detection achieved for headspace sampling of derivatised Se(IV) were in the low ng mL^–1 range for both ethylation and propylation. When the method was applied to analysis of selenite in selenised yeast reference material results were in good agreement with the indicated values.     

Solid-phase microextraction for qualitative and quantitative determination of migrated degradation products of antioxidants in an organic aqueous solution

Low molecular weight aromatic substances may migrate out from plastic packaging to their contents, especially if they consist of organic aqueous solutions or oils. It is, therefore, extremely important to be able to identify and quantify any migrated substances in such solutions, even at very low concentrations. We have in this work investigated and evaluated the use of solid-phase microextraction for the specific task of extraction from an organic aqueous solution such as a simulated pharmaceutical solution consisting of 10 vol.% ethanol in water. The goal was furthermore to investigate the possibility of simultaneously identifying and quantifying the substances in spite of differences in their chemical structures. Methods were developed and evaluated for extraction both with direct sampling and with headspace sampling. Difficulties appeared due to the ethanol in the solution and the minute amounts of substances present. We have shown that a simultaneous quantification of migrated low molecular weight degradation products of antioxidants using only one fibre is possible if the extraction method and temperature are adjusted in relation to the concentration levels of the analytes. Comparions were made with solid-phase extraction.     

Determination of L-Dopa and L-Dopamine in Aqueous Solutions Using In-Loop SPME Coupled with LC

A new in-loop solid-phase microextraction (in-loop-SPME) technique, based on an aluminum capillary tube coupled to HPLC, is described for on-line isolation, concentration, and analysis of analytes from aqueous samples. L-Dopa and L-dopamine, in aqueous solutions, were selected as model compounds. The main conditions affecting extraction of the analytes from aqueous samples, desorption, injection, and chromatographic separation were investigated. The method is simple and reproducible. Using the proposed method, reliable determination of L-dopa and L-dopamine at parts-per-billion concentrations was achieved. The calibration plots were linear in the range of 2.5–1500 ng mL⁻¹ with correlation coefficients of 0.999 and 0.998 for L-dopa and L-dopamine, respectively. The detection limits were 0.5–1 ng mL⁻¹ with a relative standard deviation less than 4.1%. Concentration factors more than 100-fold were obtained for these compounds.