The determination of sodium,potassium and magnesium in surfactants by flame spectrophotometry

A method for determining sodium, potassium, and magnesium in soaps and detergents by means of flame spectrophotometry is described in detail. Sodium and/or potassium are normally present in high percentages; magnesium is usually found in relatively low concentrations as part of the antioxidant system of bar soaps. The spectrophotometric procedure has the following advantages over commonly used wet methods: 1) rapidity, 2) simplicity, and 3) the cations are determined directly and independently of each other. Soap additives, such as perfumes, colors, super-fatting agents or germicides do not interfere with this method. Possible interferences between sodium, potassium, and magnesium cations were evaluated and eliminated. Typical examples, including toilet soaps, combination soap-detergent bars, and sprayed detergents are described. Presented at the AOCS meeting in Toronto, Canada, 1962.