TRACE ANALYSIS OF DETERGENT RESIDUES BY CAPILLARY ELECTROPHORESIS

A capillary electrophoresis (CE) method is reported which allows both specific and sensitive detection of the surfactant sodium dodecylbenzenesulphonate (SDBS) at a trace level. The method employs a simple high pH electrolyte with detection at 200 nm. This method has been applied to the monitoring of detergent residues on pharmaceutical processing equipment left after cleaning. Successful validation of the method demonstrated acceptable levels of sensitivity, recovery, precision, repeatability, robustness, detector linearity and stability of standards, reagents and samples. The CE method for determination of detergent residue was demonstrated to be selective with no interference from dissolving water or from cotton wool extracts. The method is rapid and both simple and easy to perform, and is now routinely applied to monitor detergent residues following product manufacture.