Search of components causing matrix effects on GC/MS for pesticide analysis in food

Abstract

A serious problem in analyzing pesticide residues in foods by gas chromatography/mass spectrometry (GC/MS) is the matrix enhancement effect. The matrix effect of pesticides in 5 types of representative samples preprocessed by the Positive List System was measured at 100 ppb. The mean matrix effect value of pesticides in potato, spinach, orange, brown rice, and soybean sample was 129%, 191%, 171%, 225%, and 146%, respectively. Continuing research showed that the sample solutions contained high amounts of some matrix components, such as tocopherols, sterols, and monoacylglycerols. In order to investigate which component causes the matrix effect, each matrix solution was prepared at 1–1000 ppm (monoacylglycerols: 1–500 ppm), and the pesticide mixture was fortified to 100 ppb. The matrix effect depended on the concentration of the matrix solution, and we concluded that monoacylglycerols were the most attributable components to the matrix effect.