CATALYTIC ADSORPTIVE STRIPPING VOLTAMMETRIC DETERMINATION OF ULTRATRACE LEVELS OF MOLYBDENUM IN THE PRESENCE OF ORGANIC HYDROXY-ACIDS

The adsorptive collection of the molybdenum complex with 3-methoxy-4-hydroxymandelic acid was coupled with the catalytic current of the adsorbed complex to yield an ultrasensitive voltammetric procedure for measuring picomolar levels of molybdenum. Optimum solution conditions (particularly the solution composition) were established to give a detection limit of 4 ng dm-3 (4 x 10(-11) mol dm-1) of molybdenum (following a 2 min preconcentration). The relative standard deviation (at 0.5-mu-g dm-3) was 3.7%. Possible interferences were investigated and the applicability to assays of tap water is illustrated. Such coupling of catalytic and adsorptive collection processes holds great promise for the development of ultratrace voltammetric procedures for other analytes.