Microbial Degradation of Disinfectants. III. Determination of Chlorhexidine in Waste Waters by High-Performance Liquid Chromatography after Pretreatment

The influence of materials contained in waste on the determined value of chlorhexidine was examined, and a pretreatment procedure, leading to an improved method for the determination of chlorhexidine in waste waters, was developed. It was proved that materials contained in hospital or domestic waste waters do affect the determined value of chlorhexidine. Pretreatment with acid and Celite eliminated this interference, and the recovery of chlorhexidine was satisfactory. The determined value of chlorhexidine in waste waters after pretreatment was about 5-10 times that before pretreatment, and is assumed to be closer to the true concentration of chlorhexidine in waste waters. Pretreatment of waste waters is necessary before the determination of chlorhexidine.