Determination and Identification of Anions and Cations in Cosmetics
化妆品中阴阳离子的快速测定及其用于化妆品鉴别的研究

A method was developed for the determination of anions and cations (Na~ , NH~ _4, K~ , Mg~(2 ), Ca~(2 ), Cl~-, Br~-, NO~-_2, NO~-_3 and SO~2-_4) in cosmetics by using ion chromatography with conductometric detection. The eluent for determining anions was 1,2,4,5-benzenetetracarboxylic acid (2.0 mmol/L) with 1.0 mL/min flow rate on anion exchange column (ICS-C25), while that for cations was o-phthalic acid (2.5 mmol/L) and trihydroxyaminomethane (2.4 mmol/L ) with 0.6 mL/min flow rate on cation exchange column (Shim-pack IC-A1). The ions had good linear relations in wide range, and the recoveries were from 93% to 102%.