DEVELOPMENT OF A NEW HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY METHOD TOANALYZE N-METHYLCARBAMATE INSECTICIDES BY A SIMPLE POSTCOLUMN DERIVATIZATION SYSTEM AND FLUORESCENCE DETECTION

A simple chromatographic method is proposed to analyse N-methylcarbama te insecticides by post-column derivatization and fluorescence detecti on. The new method performs the post-column reaction without the neces sity of using any delivery pumps to introduce the reagents after the a nalytical column in the chromatographic system. The simplification is possible since the hydrolysis (at basic pH) and derivatization (with o -phthaldialdehyde and 2-mercaptoethanol) reagents are present in the m obile phase. Analytical columns (which tolerate basic conditions) and pH of the mobile phase were studied. Kromasil-100-C-18 column and bera te buffer were chosen. The length and the temperature of the tubular r eactor were also optimised. Results of the validation study with the p roposed chromatographic method are shown. The values demonstrated good performance of the complete system, including the post-column derivat ization reaction. The column showed constant efficacy for more than 20 0 injections. (C) 1997 Elsevier Science B.V.