Analysis And Risk Assessment Of The Contents Of The Components Of Arsenic Speciation In Auricularia Auricula Sold In Chongqing

Auricularia auricula[Auricularia auricula(L.ex Hook.)Underw],Auricularia auricula,is an edible glial fungus with a history of thousands of years in China.At present,the industry of Auricularia auricula in China is developing rapidly.Since 2014,the cultivation scale of Auricularia auricula has been second only to mushroom,and it is the second largest variety in edible fungus cultivation in China.Auricularia auricula has a rich content of crude protein,amino acid,sugar and calcium,phosphorus,iron and other nutrients needed by the human body;meanwhile,there are many pharmacological activities such as tonifying blood,lowering blood sugar,regulating blood lipids,enhancing immune function,thus it is a popular product used as both medicine and food.However,Auricularia auricula,as a fungus,has an enrichment effect on heavy metals,so it has an abundant content of heavy metals,especially arsenic.The toxicity of arsenic in different forms is different.It is generally believed that only two inorganic arsenic forms,arsenite(As?)and arsenate(As?),have high toxicity,and the rest are low toxicity or nontoxic.There are few studies on arsenic in Auricularia auricula,but many different forms of arsenic,such as arsenite(As?),arsenate(As?),monomethyl arsenic(MMA),dimethyl arsenic(DMA),arsenic betaine(AsB),arsenic choline(AsC)and so on,are found in edible fungi such as mushroom,matsutake,truffle,boletus and green fungus.At present,GB 2762-2017 only requires the total content arsenic of edible fungi,and does not stipulate the inorganic arseniccontent in edible fungi,so it is easy to misjudge.Based on this,this experiment uses HPLC-UV-AFS to explore the arsenic speciation detection method suitable for Auricularia auricula matrix,and detects 200 groups of commercially sold Auricularia auricula samples in Chongqing.To explore the distribution of arsenic in Auricularia auricula and the risk assessment of arsenic pollution in Auricularia auricula,and to provide methods and data support for the detection and risk study of arsenic in Auricularia auricula.The main results of this experiment are as follows:1.Study on arsenic speciation in Auricularia auricula.The result shows that,taking 1 g of Auricularia auricula sample,using 15 m L of 80%methanol solution as extractant,with the condition of 640 W power and 40?,through the ultrasonic wave for 15 minutes,taking 10 m L of the liquid supernatant,repeating the above operation one more time,combine the extract,and concentrate it in a vacuum until it almost dries.HPLC-UV-AFS is used to determine the volume.The instrument conditions are as follows:0.05 mmol/L(10%ammonia to p H=9.0)and 25mmol/L(ammonia to p H=8.0)ammonium dihydrogen phosphate solution as mobile phase,with gradient elution,the current of hollow cathode lamp is 80 m A,negative pressure is 330 V,carrier gas flow rate is 300 m L/min,block gas flow rate is 900 m L/min.The HCL concentration is 8%,the KBH₄concentration is 2%and the K₂S₂O₄concentration is 1%.By this method,all the linear R²values of five arsenic forms are above 0.998,The recovery rate is above 89%.2.The analysis on arsenic speciation of 200 groups of samples.The result showed that five arsenic species were detected in Auricularia auricula.The detection rate of AsB was 87.5%,the content mean was 0.038 mg/kg.The distribution of arsenic in Auricularia auricula is more extensive than the other four species;the detection rate of organic arsenic was 93.5%,which was more than inorganic arsenic's data 87.0%;the content mean was 0.076 mg/kg,close to inorganic arsenic.Its distribution is larger than that of inorganic arsenic,while the extent is the same.And it is found that there may be other arsenic forms in Auricularia auricula that cannot be detected by HPLC-UV-AFS.In the morphological correlation analysis of five arsenic species in Auricularia auricula,There was a significant correlation between As??AsV?DMA and MMA distribution of arsenic in Auricularia auricula(p<0.05),It is assumed that during the growth of Auricularia auricula,Its internal arsenic forms may be involved in metabolism,The DMA?MMA?As?and AsV are relatively stable arsenic forms in the transformation process.In the analysis of the results of the influence of the origin on the form of arsenic in five species of Auricularia auricula,it was found that arsenic forms in Auricularia auricula may vary according to different origins.Hence it is inferred that different origins,their culture methods as well as the different sources of culture matrix will cause differences among the distribution of arsenic.3.The pollution index of inorganic arsenic of 200 batches of Auricularia auricula samples collected in this study is less than 0.6,which belongs to the first-class product,and the unqualified rate is 0.There are 2 batches of samples whose total arsenic pollution index is more than 1;8batches show between 0.6-1 and the unqualified rate is 1%.When the total arsenic content is used to determine the Auricularia auricula sample,the misjudgment will be caused in the practical test.The dietary exposure risk of 200 batches of Auricularia auricula was evaluated.The results showed that the THQ value of inorganic arsenic was 0.078,and the THQ value was much less than 1.It can be seen that the arsenic pollution of Auricularia auricula in Chongqing is not serious,and the overall edible risk grade is on the low side.According to the inorganic arsenic pollution index of Auricularia auricula in Chongqing,the risk of inorganic arsenic pollution in bulk Auricularia auricula is the same as that in prepackaged one.The risk level of the western areas in Chongqing is higher than the others,and supermarket is more risky than that of wholesale market and farmers'market.Results:With the HPLC-UV-AFS instrument,the arsenic speciation detection method suitable for Auricularia auricula matrix was found.Five arsenic speciation distributions were detected in it,and it was found that other arsenic speciation might be existing there;further research data showed that there was significant correlation between DMA?MMA?As?and AsV in Auricularia auricula,and arsenic speciation in different origins was different.Finally,the risk assessment of arsenic content in Auricularia auricula samples sold in Chongqing was implemented,and the overall edible risk grade of arsenic pollution in Auricularia auricula was low.The risk of inorganic arsenic pollution in bulk Auricularia auricula is consistent with that in prepackaged one.The risk in western Chongqing is higher than that in other areas regionally,and the risk level in supermarkets is higher than that in wholesale markets and farmers'markets.The standard of arsenic in Auricularia auricula is also discussed.