环境样品前处理技术及其进展（二）

在前文中讨论了环境样品的制备、前处理的概况，以及超临界流体萃取法。本文将继续报导近年来环境样品制备与前处理领域中其他一些新技术和新方法，包括固相萃取（ＳＰＥ）、微波溶出（ＭＷＤ）和液膜萃取（ＳＬＭ）法，阐述了这些方法的基本原理、操作过程、各种实验参数的影响，及其在环境样品制备与前处理中的应用，并探讨了该领域的发展动向。     

赛默飞世尔色谱质谱戴安产品简介

戴安产品专注于色谱及样品前处理,色谱类仪器包含离子色谱、液相色谱、各类型检测器、色谱柱耗材、色谱管理软件;样品前处理产品则涵盖了色谱分析前所需的液体萃取至固体萃取自动化操作仪器.     

离子色谱(IC)前处理法测定土壤中的总有机碳含量

本文通过IC前处理法去除土壤中的无机碳干扰,使用岛津TOC-L总有机碳分析仪及SSM-5000A固体测量单元直接测量土壤样品中总有机碳的含量.实验结果表明,该方法线性系数r良好达到0.9999,精密度RSD小于5%,分析效率高,能够满足土壤样品的分析要求.     

应用活性炭纤维型固相微萃取器定量分析化妆品中的甲醇

固相微萃取技术（Solid—Phase Micro—Extraction,SPME）是二十世纪八十年代末发展起来的一项新型无溶剂化样品前处理技术,该方法解决了传统环境样品前处理技术中使用大量有机溶剂、处理时间长、操作步骤多等缺点,成为当今环境分析化学的研究热点之一．     

使用加速溶剂萃取仪萃取氯化除草剂

加速溶剂萃取技术(简称ASE)是一种全新的高效样品前处理方法.常用的有机溶剂由泵注入已填充样品的萃取池后,加温加压,数分钟后,萃取液由载气吹入收集瓶中供分析.萃取全过程实现自动化,并且可以多次萃取,快速省时,溶剂消耗量少.分析土壤、淤泥等固体样品中的除草剂,首先要将其从基体中提取出来.从前,这一工作需要大量有机溶剂.然而在近期环境法规将就世界范围内实验室的有机溶剂用量作出许多严格的规定.例如:在美国,最近颁布的行政法规减少了联邦实验室内50—90%的溶剂用量.因此,由美国DIONEX(戴安)公司推出的减少溶剂用量的固体样品前处理方法——加速溶剂萃取应运而生.     

面向人体暴露评价的植物中抗生素分析进展

抗生素通过动物粪便或生物固体的施用、再生水灌溉进入农业土壤后可以被蔬菜和粮食作物吸收，从而引起人体的被动暴露。为了评估抗生素对人体暴露的健康风险，需要基于植物样品，发展灵敏、稳定且针对性强的分析方法。本文综述了植物样品中抗生素残留分析的研究进展，重点介绍了样品提取、净化等前处理方法及其仪器分析方法，并对植物样品中抗生素分析的研究方向进行了展望。     

典型有机磷酸酯阻燃剂分析方法研究进展

有机磷酸酯(OPEs)是一类重要的有机磷阻燃剂,近些年逐渐取代了溴代阻燃剂,广泛应用于各行各业,也因此导致在多种环境介质中有较高的暴露量和潜在风险。已有研究表明,OPEs具有一定的毒理效应,对人体及其他生物均有潜在危害。本文综述了近年来国内外OPEs的检测技术,详述了不同环境介质OPEs的前处理方法。结果表明,目前固相萃取(SPE)和固相微萃取(SPME)仍是水样前处理的主要方法;对于固体样品,加速溶剂萃取/加压液相萃取(ASE/PLE)和微波辅助萃取(MAE)应用较多;虽然大气样品仍以固体吸附剂方式为主,但已向在线一体化方向发展;而生物样品的前处理方法多与水样和固体样品方法相似;但是对于复杂环境介质中OPEs样品的前处理较为困难,方法有待改善;气相色谱-质谱联用(GC-MS)和气相色谱-氮磷检测器(GC-NPD)对弱极性和易挥发的OPEs分析效果好,而强极性和难挥发的OPEs多用液相色谱-质谱联用(LCMS);气相色谱-质谱串联(GC-MS/MS)、液相色谱-质谱串联(LC-MS/MS)和高效液相色谱-质谱串联(UPLC-MS/MS)等对多种复杂的环境介质中的OPEs均有较好的检测分析效果,但并未普及。最后,对OPEs分析测试方法的发展趋势提出了展望。     

环境样品前处理技术及其进展（一）

本文讨论了环境分析化学中样品制备及前处理技术的现状及其进展。有关环境样品的特点、前处理的目的及其作用、选择前处理技术的依据等也做了阐述。重点评述了近年来在环境分析化学领域中发展最快、用得比较普遍的几种新方法，即超临界流体萃取、固定萃取、微波溶出和液膜萃取等。（一）介绍样品前处理的原则和有关的基础，以及超临界流体萃取法；（二）其它方法及今后的发展动向（将刊登在《环境化学》１９９４年第二期）。     

面向人体暴露评价的植物中抗生素分析进展

抗生素通过动物粪便或生物固体的施用、再生水灌溉进入农业土壤后可以被蔬菜和粮食作物吸收,从而造成人体的被动暴露。为了评估抗生素对人体暴露的健康风险,需要基于植物样品,发展灵敏、稳定且针对性强的分析方法。本文综述了植物样品中抗生素残留分析的研究进展,重点介绍了样品提取、净化等前处理方法及其仪器分析方法,并对植物样品中抗生素分析的研究方向进行了展望。     

加速溶剂萃取技术及萃取系统

加速溶剂萃取技术 (ＡｃｃｅｌｅｒａｔｅｄＳｏｌｖｅｎｔＥｘｔｒａｃｔｉｏｎ ,ＡＳＥ)是在较高的温度 (5 0℃— 2 0 0℃ )和压力(1 0 0 0— 3 0 0 0ｐｓｉ)下用溶剂萃取固体或半固体样品的新颖的样品前处理方法 .在高温条件下 ,待测物从基体上的解吸和溶解动力学过程加快 ,可大大缩短提取时间 .同时由于加热的溶剂具有较强的溶解能力 ,因此 ,可减少溶剂的用量 .在萃取的过程中保持一定的压力可提高溶剂的沸点 ,使其保持液体状态 ,从而保证萃取过程的安全性 .加速溶剂萃取原理图和常用的索氏提取、超声提取相比 ,采用加速溶剂萃取技术可…     

Determination of chlorothalonil residues in coffee

Coffee beans were treated with the fungicide chlorothalonil (2,4,5,6‐tetrachloro‐1,3‐benzene‐dicarbonitrile) and the residues were determined by high‐performance liquid Chromatograph (HPLC). Several techniques including Soxhlet extraction (SE), microwave‐assisted extraction (MAE) and accelerated solvent extraction (ASE) were compared for the extraction of residues. A column clean‐up procedure was developed to remove the co‐extractives in the extract before HPLC analysis. The overall mean recoveries from extracts obtained by SE, MAE and ASE were 89.2 ±3.9, 88.4 ±1.9 and 82.8 ±0.3, respectively. The results show that MAE followed by HPLC is a viable alternative to the commonly used SE and gas Chromatographic analysis for the determination of chlorothalonil in coffee.     

土壤和沉积物中的聚合有机质对多环芳烃分布和提取的影响

为了研究土壤和沉积物中凝聚型有机碳(碳黑、干酪根)的含量及其对多环芳烃(PAHs)分布和提取的影响,分别用三氟醋酸(TFA)和在375℃下通氧燃烧的方法从珠江三角洲2个污染土壤和5个河口沉积物样品中提取酸非水解有机碳(NHC)和碳黑(BC);用索氏抽提法和不同溶剂的加速溶剂萃取法(包括连续加速萃取法ASESum和标准溶剂萃取法ASESTD)抽提土壤和沉积物中的多环芳烃,并在不同温度梯度(25℃到150℃)下用水为溶剂加速溶剂萃取其水溶态.结果表明,1)NHC是珠江三角洲土壤和沉积物中总有机碳的重要组成部分,NHC碳明显高于BC碳,NHC和BC分别占土壤和沉积物中有机碳的25.6%￣73.8%和4.64%￣17.3%.2)3种有机溶剂(丙酮、甲苯1、甲苯2)连续抽提的PAHs含量是索氏抽提的2.11倍;5种ASE方法(丙酮、甲苯1、甲苯2、ASESum、ASESTD)提取的PAHs含量与NHC含量存在明显的相关性,而且比PAHs含量与BC或无定型有机碳(AOC)含量的相关性更明显.3)在不同温度梯度下水溶态PAHs浓度符合Van’tHoff方程.研究说明除了BC外,非水解有机碳对土壤和沉积物中PAHs的分布和提取具有重要影响.     

A new procedure combining GC-MS with accelerated solvent extraction for the analysis of phthalic acid esters in contaminated soils

An optimized procedure based on gas chromatography-mass spectrometry (GC-MS) combined with accelerated solvent extraction (ASE) is developed for the analysis of six phthalic acid esters (PAEs), which are priority soil pollutants nominated by United States Environmental Protection Agency (USEPA). Quantification of PAEs in soil employs ultrasonic extraction (UE) (USEPA 3550) and ASE (USEPA 3545), followed by clean up procedures involving three different chromatography columns and two combined elution methods. GC-MS conditions under selected ion monitoring (SIM) mode are described and quality assurance and quality control (QA/QC) criteria with high accuracy and sensitivity for target analytes were achieved. Method reliability is assured with the use of an isotopically labeled PAE, di-n-butyl phthalate-d4 (DnBP-D4), as a surrogate, and benzyl benzoate (BB) as an internal standard, and with the analysis of certified reference materials (CRM). QA/QC for the developed procedure was tested in four PAE-spiked soils and one PAE-contaminated soil. The four spiked soils were originated from typical Chinese agricultural fields and the contaminated soil was obtained from an electronic waste dismantling area. Instrument detection limits (IDLs) for the six PAEs ranged 0.10–0.31 μg·L^-1 and method detection limits (MDLs) of the four spiked soils varied from a range of 20–70 μg·kg^-1 to a range of 90– 290 μg·kg^-1. Linearity of response between 20 μg·L^-1 and 2 mg·L^-1 was also established and the correlation coefficients (R) were all>0.998. Spiked soil matrix showed relative recovery rates between 75 and 120% for the six target compounds and about 93% for the surrogate substance. The developed procedure is anticipated to be highly applicable for field surveys of soil PAE pollution in China.     

加速溶剂萃取/气相色谱质谱法测定鱼类样品中的多环麝香

建立了鱼类样品中5种多环麝香的分析方法.采用加速溶剂萃取(ASE)提取,经凝胶渗透色谱(GPC)以及中性氧化铝层析柱净化后,浓缩并定容洗脱液,用GC-SIM-MS进行检测.本方法对替代物标样荧蒽-d10.的回收率为92.7%-112.9%.以六氯苯(13C)为内标,5种合成麝香的线性范围为1.0-1000.0 ng·g...     

都江堰灵岩山3种人工林优势物种叶片的有机组分特征

叶片的有机组分特征不仅是植物光合产物分配策略和养分回收的重要参数,而且是衡量凋落叶分解难易程度的重要指标.为探究不同植物群落叶片间有机组分的差异,以华西雨屏区人工林的优势乔、灌、草植物作为对象,收集其成熟叶及凋落叶,研究其水溶性组分(water soluble component,WSC)、有机溶性组分(organic...     

加速溶剂萃取-固相萃取净化-超高效液相色谱串联质谱法测定土壤中11种全氟化合物

采用超高效液相色谱-串联质谱联用法（UPLC-ESI-MS/MS）,建立了分析土壤中11种全氟化合物（PFCs）的方法.以甲醇作为萃取剂,样品经加速溶剂萃取仪（ASE）萃取,固相萃取净化后,使用UPLC-ESI-MS/MS联用仪分析样品中11种PFCs.在6 min内就可快速稳定地将所选取的11种全氟化合物分离,且最低检测浓度为0.518—3.520 pg.g-1之间,这些化合物在土壤中的平均添加回收率在71.2%—119.2%之间.应用此方法测得宜兴市水稻土样品中所选取的PFCs含量为0.006—0.780 ng.g-1之间.     

Modelling the productivity of naturalised pasture in the North Island,New Zealand: a decision tree approach

Decision tree, one of the data mining methods, has been widely used as a modelling approach and has shown better predictive ability than traditional approaches (e.g. regression). However, very little is known from the literature about how the decision tree performs in predicting pasture productivity. In this study, decision tree models were developed to investigate and predict the annual and seasonal productivity of naturalised hill-pasture in the North Island, New Zealand, and were compared with regression models with respect to model fit, validation and predictive accuracy. The results indicated that the decision tree models for annual and seasonal pasture productivity all had a smaller average squared error (ASE) and a higher percentage of correctly predicted cases than the corresponding regression models. The decision tree model for annual pasture productivity had an ASE which was only half of that of the regression model, and correctly predicted 90% of the cases in the model validation which was 10.8 percentage points higher than that of the regression model. Furthermore, the decision tree models for annual and seasonal pasture productivity also clearly revealed the relative importance of environmental and management variables in influencing pasture productivity, and the interaction among these variables. Spring rainfall was the most significant factor influencing annual pasture productivity, while hill slope was the most significant factor influencing spring and winter pasture productivity, and annual P fertiliser input and autumn rainfall were the most significant factors influencing summer and autumn pasture productivity. One limitation of using the decision tree to predict pasture productivity was that it did not generate a continuous prediction, and thus could not detect the influence of small changes in environmental and management variables on pasture productivity.     

土壤宏蛋白质组学蛋白质提取方法及其应用

土壤宏蛋白质组学在揭示土壤微生物功能、代谢与环境相互作用方面具有广阔的应用前景,但由于土壤样品的特殊性,土壤蛋白质提取步骤是限制土壤宏蛋白质组学大规模应用的瓶颈之一.本文从样品制备、提取方法、影响因素等方面综述了土壤蛋白提取方面的研究进展.一般来说,根据实验目的、蛋白种类及后续研究方法设计相应的分组成收集策略才能取得较好的提取效果.土壤总蛋白、胞内蛋白与胞外蛋白分别有不同的提取方法.总蛋白提取一般采用直接提取法;胞外蛋白不需要裂解;胞内蛋白提取方法有直接提取法和间接提取法等.裂解、浓缩、去除腐殖质的方法以及提取液、pH值的选择等也会影响提取效果.此外,简单介绍了土壤宏蛋白质组学的应用,并对今后的研究工作提出展望.表1参36