Comparison of a chemical and enzymatic extraction of arsenic from rice and an assessment of the arsenic absorption from contaminated water by cooked rice
Comparison of a chemical and enzymatic extraction of arsenic from rice and an assessment of the arsenic absorption from contaminated water by cooked rice
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DOI：
10.1021/es048150n
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发表时间：
2005-07-15
影响因子：
11.4
通讯作者：
Vela, NP
中科院分区：
文献类型：
--
作者：
Ackerman, AH;Creed, PA;Vela, NP
大米是砷形态分析的目标食物，因为其相对较高的砷浓度和人均消费率。改进的水稻形态数据有助于估计美国和地方病人群的无机砷暴露量。米饭无机砷暴露量应包括生米中的砷和从制备米饭的水中吸收的砷，以5种不同类型的米饭为材料，分别用受污染的饮用水和无砷试剂水烹饪，评价米饭在制备过程中从水中吸收的砷量。大米样品用三氟乙酸（TFA）提取，并使用IC-ICP-MS进行形态分析。TFA程序能够从五种不同的煮熟的大米样品中提取84-104%的砷（As）。色谱回收率范围为99%至116%。二甲基胂酸（DMA）和无机砷的浓度范围为22至270纳克砷/克大米和31至108纳克砷/克大米，分别为试剂水中煮熟的样品。总回收率（色谱物质总和与总消化浓度相关）范围为89%至117%。对于两种不同的受污染饮用水样品，大米对烹饪用水总量[1：1至4：1（水：大米）]中砷的吸收率在89%至105%之间。使用五种大米样品和NIST 1568 a米粉进行TFA提取与酶提取的比较。这两种提取程序产生了良好的协议无机砷DMAI和总回收率。通过使用IC-ESI-MS/ MS，母离子为m/z 153，碎片离子为m/z 138、123和105，在使用酶提取的两个大米样品中初步鉴定了二甲基硫代胂酸的结构。
Rice is a target food for arsenic speciation based analyses because of its relatively high arsenic concentration and per capita consumption rates. Improved speciation data for rice can be helpful in estimating inorganic arsenic exposures in the U.S. and in endemic populations. The inorganic arsenic exposure for cooked rice should include both the arsenic in raw rice plus the arsenic absorbed from the water used to prepare it. The amount of arsenic absorbed from water by rice during preparation was assessed using five different types of rice cooked in both contaminated drinking water and arsenic-free reagent water. The rice samples were extracted using trifluoroacetic acid (TFA) and speciated using IC-ICP-MS. The TFA procedure was able to extract 84-104% of the arsenic (As) from the five different cooked rice samples. Chromatographic recoveries ranged from 99% to 116%. The dimethylarsinic acid (DMA) and inorganic arsenic concentration ranged from 22 to 270 ng of As/g of rice and from 31 to 108 ng of As/g of rice, respectively, for samples cooked in reagent water. The overall recoveries, which relate the sum of the chromatographic species back to the total digested concentration, ranged from 89% to 117%. The absorption of arsenic by rice from the total volume of water [1:1 to 4:1 (water:rice)] used in cooking was between 89% and 105% for two different contaminated drinking water samples. A comparison of the TFA extraction to an enzymatic extraction was made using the five rice samples and NIST 1568a rice flour. The two extraction procedures produced good agreement for inorganic arsenic DMAI and the overall recovery. Through the use of IC - ESI-MS/ MS with a parent ion of m/z 153 and fragment ions of m/z 138, 123, and 105, the structure dimethylthioarsinic acid was tentatively identified in two of the rice samples using the enzymatic extraction.