The characterization of cosmetic ingredients by NMR

Abstract

NMR spectroscopic methods are presented for the routine analysis of cosmetic raw materials. The methods for the characterization of (A) paraffin hydrocarbon, (B) higher alcohol and higher fatty acid, (C) polyethylene glycol, (D) nonionic surfactant (polyethylene oxide condensate), (E) other surfactant, and (F) silicone oil are described in detail. In particular, accurate results are obtained by forming trimethylsilyl derivatives in the determination of the average chain length of (B) and (D) together with the determination of the average moles of ethoxylation of (C) and (D). In addition to the above, the application of NMR to the determination of the water content of sorbitol solution and of the composition of resorcinol monoacetate are presented.