Tolcha Teshome, Gemechu Tura, Al-Hamimi Said, Megersa Negussie, Turner Charlotta
Addis Ababa University, Department of Chemistry, P. O. Box 1176, Addis Ababa, Ethiopia.
Lund University, Department of Chemistry, Centre for Analysis and Synthesis, P. O. Box 124, SE-22100 Lund, Sweden.
Molecules. 2020 Feb 24;25(4):1012. doi: 10.3390/molecules25041012.
The excessive use of pesticides is a serious health problem due to their toxicity and bioaccumulation through the food chain. Due to the complexity of foods, the analysis of pesticides is challenging often giving large matrix effects and co-extracted compounds. To overcome this problem, a selective and "green" supercritical fluid extraction method was developed, using neat carbon dioxide as a solvent at pressures of up to 800 bars. A Box-Behnken response surface experimental design was used, with the independent variables of density (0.70-1.0 g mL), temperature (40-70 C), and volume (10-40 mL) of solvent, and the dependent variable of extracted amount of pesticides. The optimum extraction condition was found at the use of 29 mL of supercritical CO at 0.90 g mL and 53C (corresponding to 372 bars of pressure). It was observed that increasing the density of CO significantly increased the extraction recovery of endrin and 24-dichlorodiphenyldichloroethane. Matrix-matched calibration curves showed satisfactory linearity ( ≥ 0.994), and LODs ranged from 0.2 to 2.0 ng g. Precision was lower than 11% and recoveries between 80%-103%. Thus, the developed method could efficiently be used for trace analysis of pesticides in complex food matrices without the use of organic solvents.
由于农药的毒性及其通过食物链的生物累积作用，过度使用农药成为一个严重的健康问题。由于食品的复杂性，农药分析具有挑战性，常常会产生较大的基质效应和共萃取化合物。为克服这一问题，开发了一种选择性“绿色”超临界流体萃取方法，该方法使用纯二氧化碳作为溶剂，压力高达800巴。采用Box-Behnken响应面实验设计，以溶剂的密度（0.70 - 1.0 g/mL）、温度（40 - 70℃）和体积（10 - 40 mL）作为自变量，农药萃取量作为因变量。在使用29 mL超临界CO₂、密度为0.90 g/mL、温度为53℃（对应372巴压力）的条件下找到了最佳萃取条件。观察到增加CO₂的密度显著提高了异狄氏剂和2,4-二氯二苯二氯乙烷的萃取回收率。基质匹配校准曲线显示出令人满意的线性（≥0.994），检测限范围为0.2至2.0 ng/g。精密度低于11%，回收率在80% - 103%之间。因此，所开发的方法可有效地用于复杂食品基质中农药的痕量分析，而无需使用有机溶剂。
