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目的测定14种海藻样品中总砷和无机砷的含量,同时分析样品中6种砷形态。方法将海藻样品经过微波消解的前处理方法,通过电感耦合等离子体质谱(inductively coupled plasma mass spectrometry,ICP-MS)测定总砷含量;根据国标方法中无机砷检测的前处理方法,通过原子荧光光谱(atomic fluorescence spectrometry,AFS)测定无机砷含量;最后通过酸提的前处理方法,利用高效液相色谱-氢化物发生-原子荧光光谱法(high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation-atomic fluorescence spectrometry,HPLC-(UV)-HG-AFS)测定海藻样品中6种形态砷含量并与国标无机砷方法比较。结果 14种海藻样品中总砷含量为0.038~46.2 mg/kg;无机砷含量为0.006~19.3 mg/kg;对HPLC-(UV)-HG-AFS仪器的优化和方法的摸索后,从海藻样品中主要测得的砷形态为As(III)、As(V)和DMA,MMA含量较少,没有测出As B和As C。结论在砷形态较为复杂的海藻样品检测中,通过HPLC-(UV)-HG-AFS检测方法可以有效避免无机砷前处理中可能出现的有机砷向无机砷转变的现象,降低干扰,增加测试的准确性,更为具体地表现海藻样品中主要的砷形态含量。
Objective To determine the contents of total arsenic and inorganic arsenic in 14 kinds of seaweed samples and analyze the six kinds of arsenic speciation in the samples. Methods The total arsenic content of seaweed samples was determined by inductively coupled plasma mass spectrometry (ICP-MS) after pretreatment by microwave digestion. According to the pretreatment method of inorganic arsenic detection in the national standard method, atomic fluorescence spectrometry (AFS) was used to determine the content of inorganic arsenic. At the end of the experiment, the samples were extracted by high performance liquid chromatography-atomic photo-oxidation-hydride generation-atomic spectrometry fluorescence spectrometry, HPLC- (UV) -HG-AFS) were used to determine the contents of six forms of arsenic in seaweed samples and compared with the national standard inorganic arsenic method. Results The total arsenic contents in 14 seaweeds samples ranged from 0.038 to 46.2 mg / kg and the inorganic arsenic contents ranged from 0.006 to 19.3 mg / kg. After optimization of the HPLC- (UV) -HG-AFS instrument and determination of the method, The main arsenic species were As (III), As (V) and DMA, with low levels of MMA and no As and As. Conclusions In the detection of seaweed samples with complicated arsenic speciation, the possible conversion of organic arsenic to inorganic arsenic in inorganic arsenic pretreatment can be effectively avoided by HPLC- (UV) -HG-AFS, reducing the interference and increasing Accuracy, more specific representation of the main arsenic samples in the form of arsenic content.