Polarographic determination of penicilloic acid in penicillin preparations with a flow-injection system

摘要: Abstract A flow-injection method for the determination of penicilloic acid content benzylpenicillin, phenoxymethylpenicillin, ampicillin, cloxacillin and carbenicillin is described. The penicilloate detected polarographically at a dropping mercury flow-through detector mounted on conventional polarographic capillary. constant potential + 0.04 V vs. SCE applied current measured in sampled direct mode. pH 9.2 borate buffer containing 0.05% Triton X-100 used. displaces reduction wave oxygen about 400 mV towards negative potentials so that deaeration not necessary. gives linear calibration graphs 2 × 10-6–1 10-4 M solutions. relative standard deviation 10 injections 5 10-5 solution 0.2%. Results presence large amounts penicillin (the latter 10–1000-fold excess) are compared with results obtained by two titrimetric procedures.