A portable optical colorimetric sensor for the determination of promethazine in lean cocktail and pharmaceutical doses

Abstract

A low-cost, easy-to-use and portable optical colorimetric sensor determined promethazine using the oxidation of promethazine by a potassium persulfate reagent entrapped within a sol-gel polymer network. The colored reaction product was detected with a portable spectrometer. The surface morphology of the optical colorimetric sensor was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Under optimized conditions, the calibration curve of promethazine was a concentration range from 50 to 500 mg L−1 with a coefficient of determination (r2 = 0.9948). The limit of detection (LOD) and limit of quantification (LOQ) were 16.5 and 48.9 mg L−1, respectively. The intra-day precisions of the proposed method for measurement of promethazine at the concentrations of 80, 250 and 350 mg L−1 were 0.8, 4.3 and 2.4%RSD, respectively while the inter-day precisions were 1.9, 2.9 and 0.2%RSD, respectively. Accuracy of promethazine analysis ranged from 87 to 105%. The proposed device was stable for at least 90 days. The method was applied for the determination of promethazine in lean cocktail samples and pharmaceutical promethazine. The amounts of promethazine determined by the proposed method and amounts determined by spectrophotometry were not significantly different at 95% confidence level. The developed method is portable, inexpensive, easy and safe to use, consumes low amounts of sample and reagent and enables qualitative and quantitative analysis of the target analyte.