QC in soap manufacturing – total fatty matter, iodine value, and more by Vis-NIR Spectroscopy

Combined Vis-NIR spectrometer with probe

Metrohm is pleased to present a time- and cost-saving solution for the simultaneous determination of total fatty matter, iodine value as well as C8-C14 content in soap noodles. A set of 46 soap noodle samples was tested providing good results for standard error and accuracy. The application was performed on a Metrohm NIRS XDS SmartProbe Analyzer using Vision Air Software.

Control of crucial QC parameters in soap manufacturing still often relies on a mix of wet-chemical methods, mostly titration (for iodine number total fatty matter) and chromatographic methods (fatty acids). Vis-NIR Spectroscopy, on the other hand, helps to consolidate this multi-method approach but also benefits users with the inherent advantages of spectroscopic methods: It does require neither sample preparation nor consumables, there’s no waste to be disposed of, the method provides quasi real-time results, and it can applied at the push of a button.

This application demonstrates that Vis-NIR Spectroscopy is excellently suited for high throughput quality control of soap production steps. Moreover, it should be mentioned that Vis-NIR Spectroscopy can be used for the determination of additional quality parameters in soap and soap noodles like moisture, acid value, or active detergents.