Abstract

Analysis of a commercial liquid detergent handwashing product ROL Classic New 750mle from ROLCOVIANYL S.A., was performed and its soluble matter ethanolic 95^˚, 15.74%w/w of yield, was characterized by FT-IR, as well as its insoluble matter ethanolic 95^˚ 0.23w/w of yield. The anionic active matter content present in the detergent product was specified to be 11.21%w/w. The pH of the liquid detergent was determined to be 8.99 at 25 ^˚C (298K) and this alkaline pH value may have altered the optical band gap to higher values. Absorptions in IR characterizing the anionic surfactant at 1193cm^-1 and the non-ionic surfactant at 1128cm^-1 appeared in the FT-IR spectrum of soluble matter ethanolic of the detergent. Sulfonic acid appeared hydrated at 1122cm^-1 in the FT-IR spectrum of the insoluble matter ethanolic of the detergent. The reflectance ISO brightness of the detergent product was measured 8.01%. The Delta E (ΔΕ^*) value for the detergent and white standard used for calibration was calculated to be 62.9units. The optical band gap of the commercial detergent sample was calculated to be 1.174117281562370eV, using the Kubelka-Munk theory. The optical band gap value was associated to the number of carbon atoms per molecule involved in the chromophore, in the detergent sample ROL Classic, calculated to be approximately 44. Finally, a periodogram of hv eV by frequency, and a periodogram of (K/S hv)^2 by frequency were used as part of a univariate analysis, and no significant peaks in the frequency band were found.

Keywords: Diffuse reflectance spectroscopy; Surfactants; Direct two-phase titration method; Kubelka Munk equation; Optical band gap; Urea; pH