APPLICATION OF STRIPPING VOLTAMMETRY TO TRACE LEAD ANALYSIS IN INTERMEDIATES AND FINAL PRODUCTS OF SYNTHESES OF PHARMACEUTICALS

Applications of differential pulse anodic stripping voltammetry using a new pen-type renewed hanging mercury electrode have been investigate d for trace analysis of lead in pharmaceutical substances and intermed iates of their syntheses, such as procaine hydrochloride, 3-aminobenzo ic acid, methyl 4-aminobenzoate, 2-(4-chlor-3-aminobenzoyl)benzoic aci d, benzyl 2-naphthyl ether, 5-aminoisophthalic acid, 3-aminobenzoic ac id, 5-hydroxyisophthalic acid and N,N'-dibenzylethylenediamine diaceta te. Samples were dissolved in 1 M HCl or 1 hi NaOH and the electrochem ical scan was carried out. No sample mineralization was necessary. The method showed a good linearity up to 50-100 ppm Pb with a detection l imit less than 10 ppb. The results agreed well, but were more precise than those obtained by atomic absorption spectrometry using air/acetyl ene flame atomisation.