[Spectrophotometric determination of trace amount of cadmium in marine products]

The colour reaction of Cd(II) on xylend orange in the presence of hexamethylenetetramine-KNO3-HNO3 has been studied. Cd(II) forms the complex at pH = 6.2-6.4 (lambda(max) = 578.4 nm) with an apparent molar absorptivity of 1.6 x 10(4) L x mol(-1) x cm(-1). Beer's law is obeyed for Cd(II) in the range of 0.5-6 microg x mL(-1). The detection limit is 0.007 microg x mL(-1) with the recovery of 90%-105%. The method is simple and highly sensitive, and has been applied to the analysis of sample with satisfactory results.