Trace analysis of 1,10-phenanthroline based herbicide in water and soil samples.

A sensitive analytical procedure for diquat herbicide viz. 5,6-dihydropyrazino[1,2,3,4-1mn]-1,10-phenanthrolinium dichlorides in drinking water and soil samples, using differential pulse adsorptive stripping voltammetry (DPAdSV) has been developed. This involved the adsorptive accumulation of a diquat herbicide onto a hanging mercury drop electrode [accumulation potential -0.8 V vs Ag/AgCl, accumulation time 60 s, pH 7.0, ionic strength 0.1 M] for DPAdSV measurement. The detection limit for diquat herbicide was as low as 0.034 pmol L -1 level (S/N 2, RSD 2.9%) at an accumulation time of 60 s.