Using single-sweep oscillopolarograph, adsorptive wave of the complex of rhodium:2-(5-bromo-2-thiazolylazo)-5-dimethylaminobenzoic acid (stability constant 1.9 ?1012) can be obtained in pH 5.0 media of acetic acid-sodium acetate at -0.55 V (vs. SCE). By adding of cationic surfactant, cetylpyridinium chloride, the peak potential shifts about 50 mV toward neg. direction and the sensitivity increases 5 times. The peak height is linearly proportional to rhodium concentration in the ranges of 1.9 ?10-8 to 1.9 ?10-7 mol dm-3 and 1.9 ?10-7 to 1.6 ?10-6 mol dm-3; the limit of detection can reach 7.8 ?10-9 mol dm-3. The method has been used for the determination of rhodium in Rh-catalyst of mol. sieve, MgO and activated carbon with satisfactory results.

Key words: CATIONIC SURTACTANTS, PYRIDINE P, C16 COMPOUNDS, REACTION MECHANISM, CATALYST, CHLORIDE, BROMIDE, BENZENECARBOXYLIC ACID P, POLAROGRAPHIC ANALYSIS, TERNARY COMPLEX