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目的建立了离子色谱-质谱联用技术测定葡萄酒样品中柠檬酸的分析方法。方法以高容量、强亲水性的IonPac AS20型阴离子交换柱为分析柱,EGC在线产生梯度浓度KOH为淋洗液,淋洗液经捕获柱、抑制器成水后将样品带入质谱检测器。ESI-SIM监测模式监控柠檬酸根离子(m/z=191),并以峰面积进行定量。结果该方法对柠檬酸的检出限(S/N=3)为17.6μg/L,且柠檬酸浓度在50~1000μg/L范围内具有良好的线性,线性相关系数r=0.9992。200μg/L标准溶液重复进样8次,柠檬酸峰面积的相对标准偏差即精密度为0.77%。运用该方法测定市售5种不同品牌葡萄酒样品中柠檬酸的含量,并对样品加标回收,得回收率大于95%。结论该方法可以满足葡萄酒中柠檬酸定量分析的要求,且有效改善了分析的灵敏度和准确性。
Objective To establish a method for the determination of citric acid in wine samples by ion chromatography-mass spectrometry. Methods IonPac AS20 anion exchange column with high capacity and strong hydrophilicity was used as analytical column. EGC was used to generate gradient KOH as eluent. The eluent was passed through the capture column. After the inhibitor was made into water, the sample was taken to mass spectrometer . The citric acid ions (m / z = 191) were monitored by ESI-SIM monitoring mode and quantified as peak area. Results The limit of detection (S / N = 3) of citric acid was 17.6 μg / L and citric acid was linear in the range of 50-1000 μg / L. The linear correlation coefficient was 0.9992.200 μg / L The standard solution was injected 8 times repeatedly, the relative standard deviation of citric acid peak area, that is, the precision was 0.77%. This method was used to determine the citric acid content of 5 different brands of commercially available wine samples. The recovery rate was more than 95%. Conclusion This method can meet the requirements of quantitative analysis of citric acid in wine and effectively improve the sensitivity and accuracy of the analysis.