Simultaneous Assay for Ternary Mixtures of Antibiotics by a Kinetic Spectrophotometric Method Based on a Derivatization Reaction

A sensitive kinetic-spectrophotometic method for the simultaneous determination of antibiotics in a mixture, specifically of amikacin (AMK), gentamicin (GTM) and etimicin (ETM), has been researched and developed with the use of reaction kinetics. 1,2-naphthoquinone-4-sulphonate (NQS) was used as the derivative reagent to produce colored products in a medium of pH 9.02, and their spectra were collected in order to monitor the kinetics of the reaction (at 475 nm). Calibration models for quantitative analysis of these mixtures were developed with the use of the principal component regression (PCR), partial least squares (PLS) and radial basis function-artificial neural networks (RBF-ANN) methods. Verification of these models with the use of a separate set of laboratory prepared mixtures was successful with the RBFANN calibration performing best. This method was then applied for the prediction of the antibiotics in real samples - spiked injection solutions, water and serum samples, and the results were successfully verified with the use of an HPLC method. Therefore, this method is a convenient alternative to the commonly used HPLC approach for the determination of these three antibiotics in variety of samples; it also has relatively high selectivity and low-costs.