关键词: 超高效液相色谱-串联质谱, 特征性多肽, 阿胶, 胶原蛋白

Abstract:

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 ⁺) and multiple reaction monitoring (MRM) modes using the isotopic internal standard method. The optimized enzymolysis conditions were as follows: enzymolysis temperature, 37 ℃; enzymolysis time, 16 h; and amount of enzyme, 1 mL. The two marker peptides showed good linearities in the range of 50 to 1250 mg/L; the correlation coefficients (r) were greater than 0.996, and the limits of quantitation (S/N=10) were 20 mg/kg. At spiked levels of 300 mg/kg, 600 mg/kg, and 900 mg/kg, the average recovery ratios of the two marker peptides were 103.2% to 108.3%, while the relative standard deviations (RSDs) of 1.0%-3.0%. This method was favorable for testing actual samples. Asini Corii Colla from 29 production companies was detected by this method, and the sum contents of the two marker peptides was different because the production process and raw materials were different. The sum contents of the samples were 0.096% to 0.180% with an average of 0.151%. The developed method is simple, reliable, and reproducible, and it is suitable for detecting the donkey hide components Asini Corii Colla.

Key words: ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), marker peptide, Asini Corii Colla, collagen