Comparison of amperometric and UV-spectrophotometric monitoring in the HPLC analysis of pesticides

Summary Studies have been carried out to compare different detection techniques including amperometric detection in the reductive and oxidative mode and UV detection following the HPLC separation of pesticides. By the example of 4,6-dinitro-o-cresol (DNOC), 2-sec-butyl-4,6-dinitrophenol (Dinoseb) and 2-tert-butyl-4,6-dinitrophenol (Dinoterb), it is shown that the electrochemical detection exhibits higher sensitivities than the UV-technique. The detection limits are in case of the oxidative amperometric technique 0.1 ng for all pesticides, in the reductive mode 0.3 ng for DNOC and 1 ng for Dinoseb and Dinoterb. By UV-monitoring the detection limits were found to be 2 ng for DNOC and 24 ng for Dinoseb and Dinoterb.