[Simultaneous determination of 3 benzalkonium chloride homologs in cosmetics by high performance liquid...

An analytical method based on high performance liquid chromatography with a diode array detector (HPLC-DAD) has been established for the simultaneous determination of 3 benzalkonium chloride homologs (n-C12H25-C9H13NCl, n-C14H29-C9H13NCl, n-C16,H33-C9H13NCl) in cosmetics. The sample was extracted with methanol (including 0.5% formic acid) under ultrasonic operation, the HPLC separation was carried out on a CAPCELL PAK SCX column (250 mm x 4.6 mm, 5 microm), the mobile phases were 40 mmol/L ammonium acetate solution (including 0.1% triethylamine) and acetonitrile with gradient elution, the flow rate was 1.0 mL/min, the detection wavelength was 260 nm, the column temperature was 25 degrees C, and the injection volume was 20 microL. The limit of detection was 50.0 mg/kg and the quantitation limit was 200.0 mg/kg for 3 benzalkonium chloride homologs in cosmetics. The linear plots were obtained between 5.0 mg/L and 3000.0 mg/L. Overall recoveries were between 92.5% and 102.1% with the relative standard deviations (RSDs) between 3.81% and 6.66%. The method is simple, rapid, accurate and suitable for the determination of 3 benzalkonium chloride homologs in cosmetics.