Non-specific methods for detecting residues of cleaning agents during cleaning validation

Abstract

Cleaning validation procedures are carried out in order to assure that residues of cleaning agents are within acceptable limits after the cleaning process. Cleaning agents often consist of a mixture of various surfactants which are in a highly diluted state after the water rinsing procedure has been completed. This makes it difficult to find appropriate analytical methods that are sensitive enough to detect the cleaning agents. In addition, it is advantageous for the analytical methods to be simple to perform and to give results quickly. In this study, three different non-specific analytical methods are compared: visual detection of foam, pH and conductivity measurements. The analyses were performed on different dilutions of the cleaning agents Bactericidal Hydroclean and Tickopur R33. The results demonstrated that the most appropriate method for these detergents is conductivity measurements, by which it is possible to detect concentrations of cleaning agents down to 10 ?g/ml. In these case, pH is inadequate method (non-linear) and visual detection of foam is a semi-quantitative method. All these methods are easy to perform, gives a quick results, and requires no expensive instrumentation.