基质加标法在水产动物不同价态无机砷定量分析中的应用

通过对流动相种类、浓度、p H和泵速等参数进行优化,确立了分析水产动物中不同价态无机砷的基质加标-液相色谱-原子荧光光谱联用测定方法,并应用该法测定了鱼类、虾类、贝类和蟹类等样品中的砷(Ⅲ)和砷(Ⅴ)含量。结果表明,在以p H 5.5、25 mmol·L-1磷酸氢二铵溶液为流动相,泵速为60 r·min-1的检测条件下,砷(Ⅲ)和砷(Ⅴ)的回收率在94.2%~101%之间;鱼、虾、蟹类中的砷(Ⅲ)和砷(Ⅴ)检出率较低,而贝类样品的检出率较高,且不同贝类样品的砷(Ⅲ)和砷(Ⅴ)含量差异较大。通过与外标法在标准曲线、精密度和回收率等方面的比较发现,该法能够较大限度的消除基质效应的影响,校正前处理过程中的误差,对砷(Ⅲ)和砷(Ⅴ)进行准确定量。

Application of standard addition method in the quantitation of different inorganic arsenic speciation in animal-origin seafood

Arsenic has long been considered as a harmful element for people' s health.Excessive consumption or long-term intake of arsenic-rich food would damage the organs including the heart,liver,kidney,as well as the nervous system and digestive system severely.Animal-origin seafood is one of the main sources of arsenic exposure for human beings.In recent years,news on the high level of arsenic in seafood has been existing in the press from time to time due to the water pollution.As the growing acknowledgement of the toxicity of arsenic research,it has been found that the toxicity of arsenic varies with different speciations.Among numerous speciations of arsenic,most of organic arsenic are non-toxic,while the inorganic arsenic which is primarily composed of arsenic (Ⅲ) and arsenic (V) has the strongest toxicity.So it has been recognized as a carcinogen by the International Agency for Research on Cancer (IARC).Therefore,it is of great importance for the quantitative analysis of different speciations of inorganic arsenic in animal-origin seafood.Nowadays,the Liquid Chromatography-Atomic Fluorescence Spectrometry (LC-AFS) has been extensively used in the analysis of arsenic speciation in aquatic products.However,the external standard method is likely to cause the significant deviation in quantitative detection results because of the complex interfering substances in the samples and the complicated pretreatment in the practical application process for using LC-AFS to analyze the speciation of inorganic arsenic.This study creatively used the standard addition method for the quantitative analysis of different inorganic arsenic speciation in animal-origin aquatic products.A standard addition method of Liquid Chromatography coupled with Atomic Fluorescence Spectrometry was identified after the optimization of several parameters including the type,concentration,pH of the mobile phase and the pump rate.Then the content of arsenic (Ⅲ) and arsenic (V) of samples in fishes,shrimps,shells and crabs was determined by this method.The results showed that arsenic (Ⅲ) and arsenic (V) were separated optimally under the conditions of the 60 r · min-1 of the pump rate,pH 5.5 and 25 mmol · L-1 ammonium dibasic phosphate as the mobile phase.The average recovery ranged from 94.2％ to 101％.The detection rates of arsenic (Ⅲ) and arsenic (V) in shells were significantly higher than the other species.Owing to the different arsenic levels of water and sediment,different shells have different concentration of arsenic (Ⅲ) and arsenic (V).Comparing with the external standard method,this method was proved to be useful for eliminating matrix effects and correcting the errors during the process of pretreatment.