High-performance liquid chromatographic method for determination of dehydroabietic and abietic acids, the skin sensitizers in bindi adhesive

Abstract

A sensitive and selective high-performance liquid chromatographic (HPLC) method was developed for simultaneous determination of two common allergens, dehydroabietic (DHAA) and abietic acid in bindi adhesive with fluorimetric and ultraviolet (UV) absorbance detection. Bindi is a cosmetic item used by Indian women on their foreheads. The sample was ultrasonicated with 1 ml of acetonitrile for 30 min. A 0.6-ml aliquot of the extract was mixed with an equal volume of deionized water. After centrifugation, 1 ml of the supernatant was percolated through a preconditioned C18 solid-phase extraction column. After rinsing the column with 1 ml of acetonitrile-water (60:40, v/v), the analytes were eluted with 1 ml of mobile phase A and 50 μl of the eluent was used for HPLC analysis. The two mobile phases used for gradient elution were: (A) methanol-water (90:10, v/v) containing 0.06% (v/v) formic acid and (B) methanol-water (75:25, v/v) with 0.1% (v/v) formic acid. The flow-rate was set at 1.0 ml/min. DHAA was detected with fluorescence (excitation 225 nm and emission 285 nm) at 3.6 min. Abietic acid was detected at 6.1 min with UV at 238 nm. The lowest detection limits (signal-to-noise ratio 3) were 0.5 and 1.25 ng for DHAA and abietic acid, respectively. Analytical recovery and reproducibility generally exceeded 95 and 90%, respectively. DHAA and abietic acid were present in most of the bindi samples tested, with mean values 0.36 μg of DHAA (n = 26) and 0.31 μg of abietic acid (n = 24) per sample.