Development of an extraction method for the determination of avermectins in soil using supercritical CO2 modified with ethanol and liquid chromatography-tandem mass spectrometry

Authors


Correspondence: Jae-Han Shim, Natural Products Chemistry Laboratory, Biotechnology Research Institute, Chonnam National University, Yongbong-ro, Buk-gu, Gwangju, Republic of Korea

E-mail: jhshim@chonnam.ac.kr

Fax: +82-62-530-0219

Additional correspondence: Professor A. M. Abd El-Aty,

E-mail: abdelaty44@hotmail.com

Abstract

The aim of the present study was to develop a multiresidue analytical method for determination of avermectins (abamectin, ivermectin, moxidectin, and doramectin) in soil samples using supercritical fluid extraction and LC-MS/MS. The optimal extraction conditions for supercritical fluid extraction were 80°C for temperature, 300 kg/cm2 for pressure, 40 min as an extraction time, and 30% of a modifier ratio. The linearity of the calibration curves was excellent and yielded the correlation coefficients (r2 = 0.998–0.999, at a range of 1.5–500 ng/g). Soil samples were fortified with known quantities of the analytes at three different concentration levels (5, 10, and 50 ng/g) and the recoveries were in the range of 82.5–96.2% with relative standard deviation values ranging between 2.1 and 7.9%. The limits of detections and limits of quantitations were 1.5 and 5 ng/g, respectively. The developed method was successfully applied to analyze avermectin residues in soil samples collected from 13 sites in the Honam area, Republic of Korea. In sum, a combination of supercritical fluid extraction and LC-MS/MS has been proven to be highly efficient as an environmentally friendly technique for the simultaneous determination of avermectins in soil samples.

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