Analytical applications of emulsions in atomic-absorption spectrophotometry: determination of zinc in undecenoate ointments using aqueous inorganic standards

Abstract

An atomic-absorption spectrophotometric method for the determination of zinc in zinc undecenoate ointments has been developed, based on solubilisation of the sample in benzene, the formation of a stable oil-in-water emulsion using a suitable emulsifier and aspiration into the flame. Aqueous inorganic standards are used for calibration, which for emulsions might often be possible by suitable choices of both the nature and the percentage of the emulsifier. The accuracy and precision of the method are similar to those of the complexometric standard method involving mineralisation of the ointment. The proposed method has the advantages of simplicity and speed.