由于原料药2，3-吡嗪二羧酸酐易水解为有关物质2，3-吡嗪二羧酸，不能直接用高效液相色谱法测定。基于此，以甲醇衍生化2，3-吡嗪二羧酸酐后再采用高效液相色谱法测定2，3-吡嗪二羧酸酐中主成分和杂质2，3-吡嗪二羧酸、2-吡嗪甲酸的含量。按照质量体积比（mg：mL）10：7加入供试品和甲醇，超声衍生20 min，稀释后用高效液相色谱法分析。以YMC Triart C₁₈色谱柱为固定相，以不同体积比的0.5%（体积分数）三氟乙酸溶液和甲醇的混合溶液进行梯度洗脱，在270 nm处检测。结果显示：2，3-吡嗪二羧酸、2-吡嗪甲酸、2，3-吡嗪二羧酸酐之间的分离度均大于1.5，其质量浓度均在一定范围内与其对应的峰面积呈线性关系，检出限分别为0.057 5，0.054 8，0.010 2 mg·L^-1；对混合对照品溶液和供试品溶液连续分析6次，测定值的相对标准偏差均小于2.0%；2，3-吡嗪二羧酸、2-吡嗪甲酸的加标回收率分别为95.2%，98.3%；方法用于3批实际样品的分析，检出的2，3-吡嗪二羧酸酐的质量分数为97.83%~97.93%，2，3-吡嗪二羧酸的质量分数为2.07%~2.17%，而2-吡嗪甲酸未检出。

2,3-Pyrizine dicarboxylic anhydride of active pharmaceutical ingredient (API) was easily hydrolyzed to 2,3-pyrazine dicarboxylic acid of related substance, and it could not be directly determined by high performance liquid chromatography (HPLC). Based on this, after derivatizing 2,3-pyrazine dicarboxylic anhydride with methanol, the main component and impurities of 2,3-pyrazine dicarboxylic acid and 2-pyrazine formic acid in API of 2,3-pyrazine dicarboxylic anhydride were determined by HPLC. The sample and methanol were added in the mass to volume ratio (mg:mL) of 10:7, followed by ultrasonic derivatization for 20 min, and then analyzed by HPLC after dilution. YMC Triart C₁₈ column was used as the stationary phase, and a mixed solution of 0.5% (φ) trifluoroacetic acid solution and methanol at different volume ratios was used as the mobile phase for gradient elution, with detection wavelength of 270 nm. As shown by the results, the resolutions among 2,3-pyrazine dicarboxylic acid, 2-pyrazine formic acid and 2,3-pyrazine dicarboxylic anhydride were both greater than 1.5. Linear relationships between values of peak area and mass concentration of them were found in definite ranges, with detection limits of 0.057 5, 0.054 8, 0.010 2 mg·L^-1, respectively. The mixed control solution and test solution were analyzed 6 times, and RSDs of the determined values were less than 2.0%. The spiked recoveries of 2,3-pyrazine dicarboxylic acid and 2-pyrazine formic acid were 95.2% and 98.3%, respectively. This proposed method was applied for the analysis of three batches of actual samples, and the mass fraction of 2,3-pyrazine dicarboxylic anhydride and 2,3-pyrazine dicarboxylic acid were 97.83%-97.93% and 2.07%-2.17%, respectively, while 2-pyrazine formic acid was not detected.