在线捕集分离联用技术对食品调料中砷形态分析方法研究

成功建立了冷捕集-气相色谱-氢化物发生-原子荧光光谱分析测定食品调料(酱油和醋)中砷形态的方法。以脱脂棉为分离介质，用液氮对样品中生成的气态砷化合物进行冷捕集，常温下不同砷形态化合物即可以实现基线分离，随后被原子荧光光谱检测。实验考查了酸介质的种类和酸度、KBH₄溶液的浓度、反应时间以及载气(He)的流量等实验条件对测定结果的影响。结果表明，在优化后的实验条件下，方法对As(Ⅲ)，As(Ⅴ)，MMA(Ⅴ)和DMA(Ⅴ)的检出限分别为0.2，0.2，0.3，0.8 ng·mL-1，对酱油和醋As(Ⅲ)，As(Ⅴ)，MMA(Ⅴ)和DMA(Ⅴ)的回收率为93.07%～103.54%。与传统的液相色谱分离方法相比，该方法不用对样品进行特殊前处理，分析速度快，灵敏度高，适合于对食品调料中砷形态尤其是无机砷形态的准确、快速分析测定。

Analysis of Arsenic Speciation in Food Condiments Based on the Online Trapping/Separation Coupling System

An online coupling system based on gas chromatography-hydride generation with atomic fluorescence spectrometry (GC-HG-AFS) for the analysis of arsenic species in food seasoning(soy sauce and vinegar) was developed. With absorbent cotton as separation medium, the volatile arsenic species released from the samples were cold trapped online by liquid nitrogen. Then, the baseline separation of the volatile arsenic species was achieved at the room temperature and the arsenic species were sensitively detected by atomic fluorescence spectrophotometer. The experimental conditions such as flow rates of carrier gas (He), acid type and concentration, reducing reagent concentration and reaction time were discussed. Under the optimum conditions, the limit of detection for As(Ⅲ), As(Ⅴ), MMA(Ⅴ) and DMA(Ⅴ) was 0.2, 0.2, 0.3 and 0.8 ng·mL-1, respectively. The recoveries of As(Ⅲ), As(Ⅴ), MMA(Ⅴ) and DMA(Ⅴ) in soy sauce and vinegar were 93.07%～103.54%. Compared with the traditional liquid chromatography separation algorithm, the method was rapid, sensitive without any complex sample pretreatment. It was suitable and practical for detection of arsenic especially inorganic arsenic in food seasoning.