SENSITIVE AND SELECTIVE METHOD FOR THE DETERMINATION OF SODIUM MONOFLUOROACETATE BY CAPILLARY ZONE ELECTROPHORESIS

Sodium monofluoroacetate (SMFA) is a highly toxic substance and its de termination is needed in several areas. Its chromatographic (GC or HPL C) determination is difficult because of its ionic and hydrophilic pro perties. A simple, sensitive and selective capillary zone electrophore tic method is described for the determination of SMFA. It is well sepa rated from structurally related compounds (formate, acetate, chloroace tate, bromoacetate, etc.) in an acidic electrolyte buffer containing 5 mmol/l phthalate (pH 4.61) and 0.3 mmol/l cetyltrimethylammonium brom ide (CTAB) or in a basic electrolyte solution containing 5 mmol/l 4-hy droxybenzoate, 0.3 mmol/l CTAB and 10 mmol/l ammonium (pH 9.49). Good resolution was achieved at relatively low electric field (200-250 kV/c m) and CTAB concentration (0.3 mmol/l). The separation selectivity was improved in acidic phthalate buffer. Using bromoacetate as internal s tandard, the calibration graph for SMFA was linear over the concentrat ion range 1-10 mu g/ml. The detection limit was 0.4 mu ug/ml. The meth od was applied to the determination of SMFA in rodenticide baits.