Comparative chemical analysis of Indigenous Nigerian soaps with conventional ones

This study compared the chemical properties of the indigenous Nigerian soaps with the conventional soaps in order to determine whether or not they met acceptable standards. The locally made soaps were obtained from markets in Ile-Ife, Osun State and Okitipupa, Ondo State, Nigeria. The soap samples were acid digested and trace metals (Cd, Pb, Cu, Zn, and Hg) in the digested samples were profiled using Atomic Absorption Spectrometry. Documented techniques were adopted to analyze the soaps for pH, moisture content, free fatty acid, chloride content, free caustic alkali, matters insoluble in water and ethanol. The margin of safety (MoS) and hazard index (HI) associated with the use of the soaps were also evaluated. The locally made soaps had higher physicochemical properties than the conventional soaps. Mercury (Hg) had the highest concentration in the locally made soaps ranging from 106.50 ± 0.23–273.58 ± 0.49 μg/g and 46.35 ± 0.22–55.12 ± 0.65 μg/g in the conventional soaps, while Cd had the least concentration in the locally made soaps ranging from 2.95 ± 0.45–6.05 ± 0.60 μg/g and 2.88 ± 0.11–5.20 ± 0.60 μg/g in the conventional soaps. Although highly mercuric soaps are known to kill bacteria and fungi, the observed MoS (<100) and HI (>1) indicated that the soaps might be safe if only restricted to occasional use by adults and children. A careful preliminary investigation and selection of the raw materials used in the production of indigenous soaps should be considered a necessary step.