Analysis and Identification of A Semi-White Soap Bar by Infrared Absorption Spectra and a Reflectance Graph

Abstract

 A semi-white colored soap bar was analyzed, and its total fatty matter content, unsaponifiable, unsaponified and unsaponified saponifiable matter content, ethanol-insoluble matter, and free caustic alkali content were determined to be 80.2%w/w, 2.5%w/w, and 0.42%w/w, and 0.096%w/w respectively. The infrared spectra of total lipids, and unsaponifiable fats, were recorded. The Kubelka-Munk K/S value was calculated using the expression depended on reflectivity R͚ of the observed soap’s surface to be K/S=7.8683. The CIE L*a*b* value for the soap bar was found L*(C/2)=63.98, a*(C/2)=+6.30 and b*(C/2)=+26.11. From the diffuse reflectance spectra of the soap bar the band gap energy (Eg) of the material has been calculated to be 1.87409 × 10-19J for permitted indirect transitions