Determination of organic acids in disinfectants using ion-pair chromatography

The disinfection, pre-sterilisation cleaning and sterilisation of medical devices is aimed at preventing healthcare associated infections in patients and healthcare workers. Organic acid-based disinfectants are often used for pre-sterilisation cleaning and the product usually contains several active ingredients. Approximately 10?% of acid-based disinfectants contain three or more acids. Due to the similarity in chemical structure, the analysis of acids in disinfectants is difficult. This work demonstrates the possibility of using ion-pair chromatography for the determination of succinic, citric, salicylic, malic, malonic and ascorbic acids in disinfectants in the combined presence of succinic, citric, salicylic, malonic and ascorbic acids. The best separation of the mixture components was achieved using a Thermo Acclaim 120, C18, 5 ?m (4.6???150 mm) analytical column. Acetonitrile was used as eluent A and 5 mM dodecyldimethylammonium chloride solution as eluent B, adjusted to pH 2.7 with H3PO4. The analysis was performed under gradient elution conditions. Detection was performed at wavelengths of 210Р250 nm. Validation of the developed methodology was performed. The limit of detection of the proposed method is 26.76 mg/dm3 for citric acid, 20.09 mg/dm3 for malic acid, 0.66 mg/dm3 for ascorbic acid, 17.12 mg/dm3 for succinic acid, 5.89 mg/dm3 for malonic acid and 0.59 mg/dm3 for salicylic acid. Approval of the method on samples of disinfectants confirmed its high selectivity and the possibility of using it for simultaneous determination of a mixture of organic acids (malic, citric, ascorbic, malonic, succinic and salicylic acids) in disinfectants and working solutions. Keywords: organic acids, disinfectants, HPLC, ion-pair chromatography.