This article describes the development and validation of a selective high-performance liquid chromatography method that allows, after liquid-liquid extraction and pre-column derivatization reaction with quercetin, the quantification of aluminium chlorohydrate in antiperspirant creams. Chromatographic separation was achieved on an XTerra MS C18 analytical column (150 × 3.0 mm i.d., particle size 5 μm) using a mobile phase of acetonitrile:water (15:85, v/v) containing 0.08 % trifluoroacetic acid at a flow rate of 0.30 mL min-1. Ultraviolet spectrophotometric detection at 415 nm was used. The assay was linear over a concentration range of 3.7-30.6 μg mL-1 for aluminium with a limit of quantitation of 3.74 μg mL-1. Quality control samples (4.4, 17.1 and 30.6 μg mL-1) in five replicates from five different runs of analysis demonstrated intra-assay precision (% coefficient of variation <3.8 %), inter-assay precision (% coefficient of variation <5.4 %) and an overall accuracy (% recovery) between 96 and 101 %. The method was used to quantify aluminium in antiperspirant creams containing 11.0, 13.0 and 16.0 % (w/w) aluminium chlorohydrate, respectively.
Keywords: Aluminium chlorohydrate; Method development; Pre-column derivatization; Quercetin; RP-HPLC; Validation.