【摘要】 采用干法、湿法和微波消解法处理紫苏样品,以原子吸收分光光度法检测钙、镁、铜、铁、锌和锰6种微量元素的精密度和加标回收率,证实三种预处理方法会显著影响紫苏中微量元素含量的测定结果。与其它两种方法相比,用混酸HNO3-H2O2(6∶2)处理紫苏并采用微波消解样品后,各微量元素测定结果的加标回收率较高,加标回收率在99.00%～102.00%之间,相对标准偏差(RSD)低于5%。采用微波消解法对水白菜和山莴苣2种野菜样品以及油麦菜、油菜、韭菜和生菜4种绿叶蔬菜样品进行预处理表明,各微量元素的加标回收率在96.51%～99.87%之间,相对标准偏差(RSD)低于5%,这意味着对可食性植物中的微量元素检测而言,微波消解法预处理样品能够提高测定结果的准确性和重复性。更多还原

【Abstract】 Three pretreatments of vegetable samples,i.e.dry ashing,wet ashing and microwave digestion procedures,were investigated to evaluate their effects on the concentrations of trace elements including Ca,Mg,Cu,Zn,Fe and Mn by flame atomic absorption spectrometry(FAAS). Perilla frutescens,a vegetable consumed in Tianjin of China,was chosen as a case to deal with the differences occurring in the detected contents of the trace elements due to different pretreatments of samples. A higher recovery ranging from 99.00% to 102% and relative standard deviations below 5% in the detection of these trace elements were obtained when Perilla frutescens samples were pretreated with microwave digestion procedure instead of dry-ashing or wet-ashing method. Moreover,more vegetable samples including Brassica juncea var. multisecta,Lactuca indica,Lactuca sativa,Brassica napus,Allium tuberosum and Lactuca sativa var. capitata were chosen to confirm the accuracy and repeatability of microwave digestion treatment in the detection of these trace elements. It was seen that RSDs were below 5% and the ranges of the recoveries related to the assay of these trace elements varied from 96.51% to 99.87%. Obviously,using microwave digestion to pretreat edible vegetable samples can improve the determination accuracy of trace elements in food nutrition assay.更多还原