[Determination of donkey skin ingredients in Asini Corii Colla by ultra-high performance liquid chromatography-tandem mass spectrometry].

In recent years, due to the shortage of donkey skin resources, the price of Asini Corii Colla has seen a rapid increase. Consequently, fake gelatin prepared from horse, mules, pig, and cow skin has appeared in the market, resulting in unreliable quality of Asini Corii Colla. Therefore, there is an urgent need to develop an efficient and accurate method for improving the quality of Asini Corii Colla. Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to determine the donkey skin components in Asini Corii Colla. Accordingly, 0. l g of the evenly mixed sample was weighed and placed in a 50 mL volumetric flask; then, 1% ammonium bicarbonate solution was added to dissolve the sample, and the solution was diluted to the scale. Precisely 1.00 mL of the solution was extracted into a 5 mL volumetric flask, followed by the addition of 1.0 mL trypsin solution and 100 μL mixed internal standard working solution. This mixture was diluted to the scale using 1% ammonium bicarbonate solution, shaken, and placed in an incubator for 16 h to induce enzymolysis at a constant temperature of 37 ℃. The mixture was subsequently removed from the incubator, cooled to ambient temperature, filtered through a 0.22 μm membrane, and analyzed by LC-MS. Separation was performed on an UPLC system with a BEH C18 column (100 mm×2.1 mm, 2.5 μm) under gradient elution using acetonitrile containing 0.1% (v/v) formic acid (B) and water containing 0.1% (v/v) formic acid (A) as the mobile phases at a flow rate of 0.3 mL/min. The column temperature was 30 ℃, and the sample size was 2 μL. The gradient elution conditions are: 0-1 min, 10%B; 1-5 min, 10%B-30%B; 5-5.1 min, 30%B-70%B; 5.1-7 min, 70%B; 7-7.1 min, 70%B-10%B; 7.1-10 min, 10%B. The marker peptides were determined in positive electrospray ionization (ESI