Determination of Benzalkonium Chloride in a Disinfectant by UV Spectrophotometry and Gas and High-Performance Liquid Chromatography: Validation, Comparison of Characteristics, and Economic Feasibility.

Simple, fast, and validated UV-spectrophotometric, HPLC, and GC methods for the analysis of benzalkonium chloride in a disinfectant were developed. UV-spectrophotometric determination was based on measuring the amount of light absorption of aqueous solutions of benzalkonium chloride at 268 nm. HPLC determination was achieved with a 150 mm × 4.6 mm, 5.0 µm C18 column. The mobile phase consisted of a 0.01% water solution of triethylamine (with pH 2.5) and acetonitrile in the ratio of 40 : 60 v/v. The column temperature was kept at 30°C, and the injection volume was 10 µL. The flow rate was 1.0 mL/min, and the diode array detector was set at 215 nm. GC determination was performed using a flame ionization detector on a glass capillary column ZB-WAX plus 30 m × 0.25 mm with an inner coating thickness of 0.25 µm. It creates a gradient increase in the temperature of the furnace to the maximum of 200°C. The temperature of the injector was 250°C, 1 µl was injected, and the separation of the sample was 1 : 100. Helium was used as a carrier gas, and the gas flow rate was constant, equaling 1.6 ml/min. The temperature of the detector was 250°C, and a mixture of hydrogen, helium, and air in a ratio of 30 : 8.5 : 350 was used in the split of the detector. All proposed methods were validated according to ICH guidelines with respect to the accuracy, precision (interday, intraday, and reproducibility), linearity, the limit of detection, the limit of quantitation, and robustness. All three methods were linear (R 2 = 0.997-0.999) over a concentration range of 400-600 µg/ml for UV and 80-120 µg/ml for HPLC and GC, accurate (recovery was 98.4-101.7% for all methods), precise (RSD <2%), and robust. The cost of the analysis of one sample of the disinfectant for the content of benzalkonium chloride by three methods was calculated. The comparison of the obtained results facilitates a more efficient allocation of laboratory resources, depending on the goal.

Development and validation of the spectrophotometric method of butaphosphan determination in veterinary preparations.

A simple and sensitive method has been developed for the determination of butaphosphan in single- and multi-component veterinary preparations. The method is based on the combustion of organic matter prior to the formation of phosphate and the subsequent formation of the phosphoric­molybdenum complex in the presence of molybdate and ascorbic acid as a reducing agent in the sulfate acid medium. The intensity of light absorption of the colored analytical form of "molybdenum blue" is measured at a wavelength of 830 nm in the range of 0.3-9.0 µg/ml of butaphosphan, where Beer's law is obeyed, has been measured. The reaction conditions and other experimental parameters influencing the reaction transition and the stability of the colored complex have been thoroughly investigated and optimized for the quantitative determination of butaphosphan. Validation of the developed method according to the requirements has been carried out State Pharmacopoeia of Ukraine garmonised with European Pharmacopoeia and its suitability for the analysis of the selected veterinary preparations for the quantitative content of butaphosfan has been confirmed. The results of the determination of butaphosphan in six veterinary preparations of domestic and imported products have been obtained with the help of the developed method. The received results are in agreement with the results obtained by the method of potentiometric titration.