Determination of fungistatic quaternary ammonium compounds in beverages and water samples by high-performance liquid chromatography

Abstract

Fungistatic and fungicidal quaternary alkylammonium compounds are widely used in the prevention of staining of timber. They may also find application in the steeping of barley for restricting the growth of fungi. Although they show only low toxicity, sensitive methods are required for their trace determinations as contaminants in food products and water. Problems arise with their analysis because they are of low volatility, they do not carry any chromphore and they are difficult to derivatize. The traditional method for their determination has been based on ion-pair extraction followed by photometric detection. Naturally such a system has low selectivity and is therefore most suitable for quality control purposes. Ion-pair extraction has also been applied as a detection system after high-performance liquid chromatographic (HPLC) separation’, and the other method applied is so-called vacancy chromatography’. The former method requires specific equipment and the latter is susceptible to disturbances from the matrix. The use of a refractive index detector, although possible for various formulations3, is normally affected by other substances in more complicated matrices. The aim of this study was to develop a simple procedure for the determination of quaternary alkylamines at the pg/ml level.