Development and Validation of Method for Determination of Chloride in Surfactant Sample Using Auto-Titrator

Abstract

The chloride content for the newly developed surfactant is critical to ensure reaction completion and to minimize irritation issues that may be associated with having high chloride content. There are several methods used to determine the chloride content such as UV-visible and ion chromatography; however, both are known to have low accuracy and are less precise. Considering other factors such as skill, expertise, cost and time required, titration is the most suitable method for chloride determination because it is a simple, fast and relatively cheap method as compared to other methods. However, the precision achieved by manual titration is very much dependent on the operator's skill and ability to detect the color change accurately. To increase the precision and accuracy of the results generated, an auto-titrator that employs potentiometric sensors to determine the endpoint has been used to determine the chloride content. An improved method to determine the presence of chloride in surfactant solution is hereby illustrated, in which a commercial surfactant has been analyzed using the auto-titrator. A commercial surfactant known as Cola Teric CBS with a sodium chloride content of 5.7% as stated in the Certificate of Assurance (COA) was analyzed using this method. Fifteen replicate titrations of the sample giving the average chloride content of 3.5%. The precision for both method and system was found to be 0.28% and 2.22% respectively, which is within the acceptable limit. The good precision achieved by this method concludes the intention of the work to develop a method that ensures the endpoint can be determined accurately with better reproducibility, reduced titrant, sample and not operator dependent.