Zl. Jiang et Ah. Liang, CATALYTIC KINETIC DETERMINATION OF TRACE AMOUNTS OF ASCORBIC-ACID WITH SINGLE-SWEEP OSCILLOPOLAROGRAPHY, Analytica chimica acta, 278(1), 1993, pp. 53-58
A highly sensitive and selective catalytic method with single-sweep d.
c. oscillopolarographic detection is described for the determination o
f ascorbic acid, based on its activation effect on the slow vanadium(V
)-catalysed reaction of BrO3- and methyl orange in sulphuric acid medi
um at 60-degrees-C. The oxidation product of methyl orange exhibits a
polarographic wave at -0.40 V vs. SCE in the supporting electrolyte of
sodium hydroxide, and was chosen as the indicator component for the i
ndicator reaction. A calibration graph between 8 and 160 ng ml-1 ascor
bic acid was obtained by the fixed-time procedure. The detection limit
was 4 ng ml-1. Possible interferences by co-existing substances were
examined.