1-Glyceryl Monooleate as an Effective Agent for Improving the Response Factor and Expanding the Linearity Range of the Analytical Signal in the Determination of Trace Pesticides by Gas Chromatography

Resumo

We studied the effect of 1-glyceryl monooleate additions on the response factor and linearity range of the analytical signal in the determination of trace amounts of 56 pesticides of various classes (amides, carbamates, imidazoles, morpholines, pyrazoles, pyrimidines, triazoles, etc.) by gas chromatography with mass spectrometric detection. An optimal concentration range of 1-glyceryl monooleate was found, which, simultaneously with improving the shape of the chromatographic peak (increasing height, decreasing broadening), ensures the expansion of the concentration limit of the signal linearity and lowers the limit of detection for pesticides in their determination in agricultural products. In contrast to the currently used sorbitol, D(+)-gluconic acid δ-lactone, and shikimic acid, 1-glyceryl monooleate exhibit better thermal stability under gas-chromatographic determination (in helium medium) and better solubility in organic solvents, especially, in nonpolar ones (hexane). The use of 1-glyceryl monooleate as an addition reduces the contamination of the liner of the chromatograph injector and column, eliminates the instability of substance concentrations in the solution and a possibility of their precipitation, and minimizes the likelihood of the syringe plunger rod getting stuck when the sample is injected. Thus, there is no need to flush the syringe thoroughly with water or an aqueous-organic mixture after each injection.