Simultaneous Determination of 41 Anti-Inflammatory and Analgesic Compounds in Kangguzengsheng Tablets by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

The 20 Kangguzengsheng tablet samples were taken, removed of the coating and ground finely. An aliquot (1 g) of powder was taken, and 25 mL of 50% (volume fraction) methanol solution was added. The mixture was ultrasonicated for 30 min at a water temperature not exceeding 60 ℃, shaken well and passed through a 0.22 μm filter membrane. The filtrate was determined by ultra-high performance liquid chromatography-tandem mass spectrometry. In chromatographic analysis, a Welch Ultimate UHPLC XB-C₁₈ column (100 mm×2.1 mm, 1.8 μm) was used as the stationary phase, and a mixture of acetonitrile and 0.1% (volume fraction) formic acid solution containing 5 mmol·L⁻¹ ammonium acetate at different volume ratios was used as the mobile phase for gradient elution. In mass spectrometry, positive and negative ion modes of electrospray ion source were used for ionization, multiple reaction monitoring mode was used for detection, and external standard method was used for quantification. It was shown that linear relationships between the peak areas of the corresponding quantitative ions and mass concentrations of 41 anti-inflammatory and analgesic compounds were kept in definite ranges, with correlation coefficients greater than 0.991 0 and detection limits (3S/N) of 0.1−2 μg·L⁻¹. Test for recovery was made according to the standard addition method, giving recoveries in the range of 64.0%−114%, and RSDs (n=6) of the determined values were less than 11%. The proposed method was used for the analysis of 57 batches of samples from 33 production enterprises, and aspirin was detected in all samples. The source of aspirin needed further experimental exploration. Acetaminophen was detected in 3 samples, presumable due to cross contamination during the production process. The detected levels of aspirin and acetaminophen were much lower than the minimum daily dose of the corresponding drugs.