Direct chemiluminescence determination of penicillin G potassium and a chemometrical optimization approach

A highly selective and simple chemiluminescence (CL) method for determination of penicillin G potassium (PGK) was developed. In the proposed method, CL was elicited from PGK upon its oxidation with H 2 O 2 . The light emission was enhanced in the presence of N ‐cetyl‐ N , N , N ‐trimethylammonium bromide (CTMAB). An experimental design, central composite design (CCD), was used to realize the optimized variables, including pH, surfactant (CTMAB) and H 2 O 2 concentrations. Under optimum condition, the calibration graph was linear in the range 3.3 × 10 −3 –3.3 × 10 −1  mmol/L, with a detection limit of 8.8 × 10 −4  mmol/L for PGK. The precision was calculated by analysing samples containing 1.6 × 10 −1  mmol/L PGK ( n  = 5) and the relative standard deviation (RSD) was 1.40%. The utility of this method was demonstrated by determining PGK in pharmaceutical formulations for injection. The proposed method was validated by a reference method. Copyright © 2011 John Wiley & Sons, Ltd.