液相色谱法测定土壤中四环素含量前处理方法的优化

Improvement of Pretreatment for Determination of Content of Tetracycline in Soil with Liquid Chromatography

为了准确测定土壤四环素含量,科学合理开展四环素污染土壤治理及利用,基于已有的液相色谱四环素测定方法,从浸提剂的选择、浸提液固相萃取的方法及溶解液的选择入手,比较了不同组合前处理下的土壤四环素提取率差异。结果显示最优的土壤四环素测定前处理方法为:选择草酸/乙醇作为萃取溶剂,2 mL甲醇、2 mL超纯水活化Oasis HLB固相萃取柱,浸提液以1 mL/min的速率通过Oasis HLB固相萃取柱进行富集,5 mL超纯水、5 mL甲醇-水(5∶95,V/V)淋洗,减压抽干10 min后用5 mL的甲醇溶液缓慢洗脱,石英蒸发皿中40℃下水浴蒸发至近干,2 mL色谱纯甲醇搅拌溶解,之后过0.22μm滤膜。该方法四环素提取率可达100%,可有效提高土壤中四环素含量测定的效率与准确性。

To accurately determine the content of tetracycline in soil and scientifically and rationally carry out the remediation and utilization of tetracycline-contaminated soil,the differences of extraction rate of tetracycline in soil under various combinations of pretreatment were analyzed on the basis of existing liquid chromatography method for tetracycline determination.The pretreatment includes three aspects,the choice of extractants,the approache of solid-phase extraction and the selection of solvents.The result shows that the optimal pretreatment method for the determination of tetracycline in soil is as follows:oxalic acid/ethanol is used as the extractant,and the extract is enriched when flowing through the Oasis HLB solidphase column,which is activated by 2 mL of methanol and 2 mL of ultrapure water at a flow rate of 1 mL/min,and then washed by 5 mL of ultrapure water and 5 mL of methanol water(5∶95,V/V);the extraction column is pumped and drained under reduced pressure for 10 min,and slowly eluted by 5 mL methanol,and then is evaporated to be nearly dry with hot water(40℃)in a quartz evaporating dish;finally,the product is stirred and dissolved in 2 mL of methanol(chromatographically pure),followed by being filtered with 0.22μm filter.With this method,the extraction rate of tetracycline is 100%,which can effectively improve the efficiency and accuracy of the determination of tetracycline in soil.