Relative Retention Time Diagram as a Useful Tool for Gas Chromatographic Analysis and Electron-Capture Detection of Pesticides

Abstract

Abstract To establish efficient operating conditions for gas chromatographic (GC) analysis of pesticides that are detected by electron-capture detector (ECD), separation degrees of 40 pesticides and their relative retention times (RRT) vs aldrin were determined. Eleven liquid phases, categorized according to the McReynolds constant (MC), were used: OV-1, OV- 3, DC-550, and OV-17 as non- or low polar liquid phases (MC ≦ 1000), OV-22, QF-1, and XE-60 as medium polar liquid phases (1000 < MC ≦ 2000), PEG-20M, DEGA, and DEGS as high polar liquid phases (2000 < MC), and a mixture of DC-200 and EPON1009. An RRT diagram was prepared by plotting the RRT of each pesticide on the horizontal axis and the MC values on the vertical axis. The RRT diagram could be used to describe the properties of pesticides—their behavior on each liquid phase and the precise operational conditions for qualitative GC analysis. The non- or low polar liquid phases were best suited for GC analysis of organochlorine pesticides having low polarity. Their detection limits ranged from 0.01 to 1.0 ng.