Determination of traces of streptomycin and related antibiotics by adsorptive stripping voltammetry

Adsorptive stripping voltammetry provides sensitive determinations of trace amounts of the saccharide-related antibiotics, streptomycin, erythromycin and novobiocin. A static mercury drop electrode is immersed in a stirred alkaline solution of the drug for a fixed time (60–300 s) at a suitable potential, and the adsorbed species is then stripped in the linear-scan or differential-pulse mode. The preconcentration potentials and stripping peak potentials (vs. Ag/AgCl) are, respectively, ?1.0 V and ?1.58 V for streptomycin, ?0.9 V and ?1.2 V for erythromycin, and ?1.0 V and ?1.38 V for novobiocin. The interfacial behavior is discussed. Short preconcentration periods suffice to quantity streptomycin, novobiocin, and erythromycin down to the 7 × 10^?10 M, 2.5 × 10^?9 M, and 1.3 × 10^?8 M levels, respectively. Streptomycin added to urine can be quantified after simple dilution.