APPLICATION NOTE Molecular Spectroscopy Authors: Kenneth Way Chiang Poh PerkinElmer, Inc. Petaling Jaya, Malaysia Sample Preparation for Quality Control of Soap Noodle Parameters Using the PerkinElmer Frontier FT-MIR/NIR System Rapid FT-IR-ATR and FT-NIR Introduction Soaps are essential to personal and public health. They safely remove germs, soils and other contaminants and help us to stay healthy and make our surroundings more pleasant. Soaps are made from fats and oils or their fatty acids. Soaps are sodium or potassium salts of long chain fatty acids. When triglycerides in fat/oil react with aqueous NaOH or KOH, they are converted into soap and glycerol. This is called alkaline hydrolysis of esters. Since this reaction leads to the formation of soap, it is called the saponification process (Figure 1). The saponification reaction is exothermic in nature, because heat is liberated during the process. The soap formed remains in suspension form in the mixture. Soap is precipitated as a solid from the suspension by adding common salt to the suspension. This process is called Salting out of Soap. i> Perkin Elme ’ For the Better

If the saponification reaction is ineffective, free fatty acid (FFA) is presented. This would modify the alkalinity of the soap condition and affects its downstream applications. Figure 1. Saponification Process. Various wet chemistry methods are used in the quality control of soap noodle parameters such as Fatty Acid composition (FAC), Free Fatty acid (FFA), Total Fatty Matter (TFM), Glycine (Gly), Moisture (MI), Ethylene Diamine Tri-acetic Acid (EDTA), etc. The chemicals used in these wet chemistry methods in laboratories in the soap making industry runs into millions of dollars every year....

Figure 3. Calibration Models for Soap Noodle Parameters- FFA, TFM, Gly, H2O, EDTA and NaCl. Table 1. FT-NIR-NIRA and FT-IR-UATR Method Calibration Summaries for Soap Noodle Application.

Figure 4. Calibration Models for Fatty Acid Composition (FAC) for C12 C 14. Conclusion Both FT-NIR-NIRA and FT-IR-UATR methods worked well for the soap noodle application. The calibration models of these quality control parameters shown above depicted a high percent variance. It could be further improved with more samples to cover the gaps and with a wider composition range (Figure 3 and 4, Tables 1 and 2 ). PerkinElmer Frontier FT-MIR/NIR system with an UATR accessory provides an alternative rapid analytical tool to the wet chemistry reference methods for quality control soap noodles parameters....