| Edible fungi has the capacity of heavy metal-enrichment.In recent years,more atten-tion has been mainly focused on the determination of heavy metals and arsenic content in edible fungi,however the research on chemical speciation of heavy metals and arsenic is relatively lacking.Therefore,it is very essential to research the chemical speciation of heavy metals and arsenic in edible fungi,which is of great siginificance to ensure food se-curity of edible fungi.The main results are concluded as follows:1.The content of Pb,Cd,Cr,Cu in four kinds of edible fungi(Auricularia auricular,Lentinus edodes,Flammulina velutipes and Grifola frondosa)samples in this study was de-termined by inductively coupled plasma optical emission spectrometry(ICP-OES).It was shown that the content was within the national standards except Cd.2.Chemical speciations of heavy metals in four kinds of edible fungi(Auricularia auricular,Lentinus edodes,Flammulina velutipes and Grifola frondosa)samples in this study were carried out by Tessier sequential extraction procedure.The results showed that in the four kinds of edible fungi samples,Pb was mainly in forms of carbonates,Fe-Mn oxides and organic matter etc;Cd was mainly in forms of water soluble,Fe-Mn oxides,or-ganic matter and residual in Flammulina velutipes,while it was mainly in forms of water soluble and exchangeable in other three kinds of edible fungi;Cr was mainly in forms of organic matter and residual etc;Cu was mainly in form of organic matter in Auricularia auricular,while it was mainly in forms of water soluble in other three kinds of edible fungi.3.The article established an analysis method of five arsenic speciations including As(III),As(V),MMA,DMA and AsB in edible fungi by high-performance liquid chroma-tography-inductively coupled plasma mass spectrometry(HPLC-ICP-MS).It was shown that the five arsenic speciations were completely separated by using 5mM phosphate solu-tion(the pH was 6.0)as mobile phase,based on the flow rate of 0.7mL/min.The method showed a good linearity in the concentration range of 1?40?g/L with accepted accuracy and precision.Calculated recoveries were 93.58%?104.75%,it could satisfy the requirement of analysis.4.The content of arsenic in four kinds of edible fungi(Auricularia auricular,Len-tinus edodes,Flammulina velutipes and Grifola frondosa)was determined by inductively coupled plasma optical emission spectrometry(ICP-OES),compared the arsenic extract efficiency of water,acetic acid,phosphoric acid and methanol,and used high-performance liquid chromatography-inductively coupled plasma mass spectrometry(HPLC-ICP-MS)to analyze the chemical speciation of arsenic in edible fungi.The results showed that the order from high to low of arsenic content was Auricularia auricular>Grifola frondosa>Flammulina velutipes>Lentinus edodes;the extract efficiency of acetic acid was superior to the other extracting agents.The main arsenic speciations in Auricularia auricular and Grifola frondosa were As(?),MMA,DMA and AsB,while the main arsenic speciations in Lentinus edodes and Flammmulina velutipes were As(?),MMA and DMA,the proportion of inorganic arsenic in edible fungi was only 16.79%-27.51%,existing by organic arsenic with low toxicity mostly.5.Studied the effect on the content,chemical speciation of heavy metals and arsenic in Lentinus edodes by drying(hot air drying,vacuum freeze drying)and soaking treatments.It was shown that the effect of two drying methods on the content of heavy metals(Pb,Cd,Cr and Cu)was not significant(p>0.05),hot air drying could decrease the arsenic content by 3.08%(p<0.05),while the effect of vacuum freeze drying was not significant(p>0.05);after hot air drying,the lively speciations of Pb,Cd,and Cu were decreased,the stable spe-ciations were increased,it could make the content of As(?)increased significantly(p<0.05),MMA and DMA decreased significantly(p<0.05);after vacuum freeze drying,the lively speciations of Pb,Cd,and Cu were increased,the stable speciations were decreased,its effect on various speciations of arsenic was not significant(p>0.05),the effect on chemical speciation of Cr by two drying methods was opposite to Pb,Cd,and Cu.Soaking treatment could reduce the content and every speciation of heavy metals and arsenic in Lentinus edodes,especially the speciation with lively nature and high toxicity. |
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