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 dodecylbenze nesulphonate (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 dem onstrated acceptable levels of sensitivity, recovery, precision, repea tability, robustness, detector linearity and stability of standards, r eagents and samples. The CE method for determination of detergent resi due was demonstrated to be selective with no interference from dissolv ing water or from cotton wool extracts. The method is rapid and both s imple and easy to perform, and is now routinely applied to monitor det ergent residues following product manufacture.