Document Type : Research Paper
Slovak University of Technology in Bratislava, Faculty of Chemical and Food Technology, Institute of Analytical Chemistry, Radlinského 9, SK-812 37 Bratislava, Slovak Republic
The quantitative results in the pesticide residue analysis by gas chromatography-mass spectrometry are adversely affected by the phenomenon known as the matrix effects. A matrix effect may be noticed as an increase or decrease in the response of the detector signal compared with the response produced by solvent solutions of the analytes. The purpose of this research is to evaluate and compare the matrix effects in two nutraceutical samples (Alpa and Alpa Lesana), containing alcohol and herbal extracts. Samples were extracted by dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry analysis. Thirty-eight pesticides from different chemical classes were used to evaluate the matrix effects. Matrix effects were studied by calculating the matrix factor for each pesticide for the two herbal-based potions. The method was validated in terms of trueness (recoveries 70 % - 120 %), precision (below 20 %), linearity (correlation coefficients for Alpa higher than 0.98; for Alpa Lesana in the range of 0.83 to 0.99), and the limits of detection (0.001 µg/L - 0.780 µg/L (Alpa); 0.014 µg/L - 0.812 µg/L for Alpa Lesana). The present study revealed the strong dependence of matrix effects on the sample type and the complexity of the matrix. Most of the pesticides showed strong signal enhancement in the case of Alpa Lesana analysis. On the other hand, most of the pesticides were influenced only minimally in the case of Alpa analysis. To compensate the matrix effects, the utilization matrix match standard solutions for calibration is recommended for both samples.