Fourier-Transform Infrared Spectroscopy and Gas Chromatography-Mass Spectrometry Characterization of Arachis Oil for Production of Laundry Soap

Abstract

The study aimed to extract oil from Arachis seeds (Arachis hypogaea), characterize the oil with FTIR and GC-MS, and use it to produce laundry soap. Arachis oil was extracted via the Soxhlet method in nhexane. Standard methods were adopted to examine the properties of the extracted oil, and the produced laundry soap. Fourier-Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectrometry (GC-MS) were used to analyze the chemical composition of the oil. The results showed that 70.0 g of the Arachis seed gave 49.56±1.24 % oil yield. The physicochemical characterization of the oil showed that the relative density, saponification value, acid value, and iodine value were 0.65±0.15 g/mL, 190.74±2.17 mgKOH/g, 2.08±0.15 mgKOH/g, and 91.88±0.25 gI2/100g, respectively. Functional groups analysis from FTIR data revealed unique absorption peaks of methyl group at 1379 cm–1, methylene group at 723, 1461, 2847, 2922 cm–1, carbonyl group at 1744 cm–1, and olefin group at 1654 cm–1, which are attributed to the fatty acids present in the Arachis oil. The GC-MS analysis confirmed the following fatty acids: Oleic acid, Elaidic acid, and Vaccenic acid in the oil. The soap’s quality parameters determination offered 99.75±0.26 cm, 4.63±0.37 cm, 7.10±0.78 % and 59.25±2.65 % for pH, foam height, moisture content and total fatty matter, respectively. Besides, the soap was slightly pinkish and moderately hard. The findings of the study proved that Arachis seeds oil is a rich
source of fatty acids with the required functional groups for efficient saponification reaction, and has a huge potential for large-scale production of quality laundry soap.