Abstract: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established to determine abietic acid and dehydrogenated abietic acid in livestock and poultry skin. Samples were extracted with acetonitrile, and the extract was purified with an HLB solid-phase extraction (SPE) cartridge before analysis by LC-MS/MS. The chromatographic separation was accomplished on a C18 column (100 mm × 2.1 mm, 2 μm) with a mobile phase consisting of 0.1% formic acid solution and 0.1% formic acid-methanol solution (10:90, V/V) at a flow rate of 0.3 mL/min. The analysis was achieved by using an electrospray ionization (ESI) source in the positive ion mode with multiple reaction monitoring. The linear range, detection limit and quantification limit were 2.0–100 μg/L, 1.1 μg/kg, and 3.6 μg/kg for abietic acid; and 5.0–250 μg/L, 3.9 μg/kg, and 13 μg/kg for dehydrogenated abietic acid, respectively. The recovery rates of spiked samples at three different concentration levels of 5.0, 10 and 50 μg/kg for abietic acid and of 20, 40 and 200 μg/kg for dehydrogenated abietic acid were in the range of 81.7%–93.7%, with relative standard deviations (RSDs) within 12%. The developed method was successfully applied for the analysis of several real samples. Both abietic acid and dehydrogenated abietic acid were detected in some samples including duck skin dehaired with rosin glyceride. This analytical method proved to be simple, fast, sensitive and reliable, and could be used for confirmatory and quantitative analysis of abietic acid and dehydrogenated abietic acid in livestock and poultry skin.

Key words: liquid chromatography-tandem mass spectrometry; livestock; abietic acid; dehydrogenated abietic acid