Sample enrichment for determination of chlorinated pesticides in water and soil by chromatographic extraction
Sample enrichment for determination of chlorinated pesticides in water and soil by chromatographic extraction
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色谱萃取法测定水和土壤中氯化农药的样品富集
DOI：
10.1021/ac00234a019
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发表时间：
1981
影响因子：
7.4
通讯作者：
F. Bruner
中科院分区：
文献类型：
--
作者：
F. Mangani;G. Crescentini;F. Bruner
几份报告和论文（2-5）描述了在分析水样中的氯农药含量之前，使用Tenax GC和Carbopack B等吸附剂富集水样。还报告了使用适当的溶剂混合物洗脱从土壤样品中提取农药的方法（6）。这种方法显示了一些优点，无论是在通常的溶剂萃取使用分液漏斗的水和索氏提取土壤。本文详细研究了利用色谱技术从水和土壤样品中提取农药的可能性。必须指出的是，尽管在水分析中的吸附和萃取过程以及在土壤分析中的萃取过程的原理与液-固色谱法的原理相同，但色谱柱的主要特征，即分离效率，几乎完全不存在。因此，用于提取的“柱”应被视为提取装置而不是实际的色谱柱。对于水分析，短柱填充有Carbopack B，一种非常知名的石墨化炭黑。其主要应用是作为气-液-固色谱的固体载体（7）。这种材料也可用于空气污染分析中样品富集的捕集器（8）。水可以通过Carbopack B柱，感兴趣的化合物被吸附在石墨化表面上。然后，将适当的溶剂混合物引入柱中，以将农药从石墨化炭黑中除去。对于土壤分析，根据下文描述的程序用土壤填充柱。土壤就像一种吸附剂，将农药保留在其表面。这些通过溶剂混合物洗脱，所述溶剂混合物应针对适当的极性特征进行选择。这两种洗脱过程在吸附剂的性质以及吸附过程的故事方面不同。事实上，杀虫剂可能在分析前几年就已经在土壤中散布了。浇水的连续作用改变了原始的吸附能分布，使材料结构中更深、更强的吸附位点可用。已经测试了几种溶剂或溶剂混合物，以找到对最多数量的化合物具有最佳提取能力的溶剂。所研究的农药结构复杂。实验部分萃取柱的制备.对于水分析，Carbopack B（Supelco Inc.贝莱丰特，PA）用石油醚-甲苯2：1溶液通过索氏提取6小时，然后干燥并轻轻填充在1 cm内径× 15 cm的玻璃柱中。使用1克Carbopack B。两个玻璃棉塞将吸附剂保持在适当位置。柱的上部通过毛玻璃接头连接到含有待分析水的分液漏斗。一
The use of adsorbents such as Tenax GC and Carbopack B for the enrichment of water samples prior to the analysis of theirchloropesticide content has been described in several reports and papers (2-5). Pesticide extraction from soil samples usingelution with appropriate solvent mixtures has also been reported (6). Such methods show some advantages both on the usual solvent extraction using a separatory funnel for waterand on Soxhlet extraction for soil. In this paper a detailed investigation on the possibilities of using chromatographic techniques for the extraction of pesticides from water and soil samples is reported. It has to be noted that, although the principles governing the adsorption and extraction process in water analysis andthe extraction in soil analysis are the same as those that govern liquid-solid chromatography, the main feature of a chromatographic column, ie, separation efficiency, is almost completely absent. Thus, the “columns” used for the extraction should be regarded rather as an extraction apparatus than actual chromatographic columns. For water analysis, a short column is packed with Carbopack B, a very well-known graphitized carbon black. This has its main application as a solid support for gas-liquid-solid chromatography (7). This material is also used to make traps for sample enrichment in airpollution analysis (8).Water is allowed to pass through the Carbopack B column and the compounds of interest are adsorbed on the graphitized surface. Afterward, an appropriate solvent mixture is intro-duced into thecolumn, to elute the pesticides from the gra-phitized carbon black. For soil analysis, a column is packed with soil according to the procedure described later. The soil behaves as an adsorbent that retains pesticides on its surface. These are eluted by a solvent mixture, that should be chosen for appropriate polarity characteristics. The two elution processes differ in the nature of the ad-sorbents and also in the story of the adsorption process. In fact, pesticides might havebeen spread over the soil several years before the analysis. The successive action of watering modifies the original adsorption energy distribution, making available deeper and stronger adsorption sites in the structure of the material. Several solvents or solvent mixtures have been tested in order to find the one with the best extracting power for the highest number of compounds. The pesticides investigated are structurally complex. EXPERIMENTAL SECTION Preparation of Extraction Columns. For water analysis Carbopack B (Supelco Inc. Bellefonte, PA) previously sieved to 60-80 mesh was extracted by Soxhlet for 6 h with a petroleum ether-toluene 2: 1 solution and then dried and packed gently in a glass column of 1 cm id X 15 cm. One gram of Carbopack B was used. Two glass wool plugs kept the adsorbent in place. The upper part of the column was connected via a ground glass joint to a separatory funnel containing the water to be analyzed. A