Study On Content Detection Of Rare Earth Elements In Tea Substitute

Tea substitute is substitute for tea.At present,research on Rare Earth(RE)in tea substitute and testing is rare.This article aimed to comprehend the content of RE elements in tea substitute,provide testing data for the quality and safety risk assessment of tea substitute.This paper adopted ICP-MS to measure 16 kinds of RE elements content in selected main tea substitute product samples in the market.Meanwhile,the test data and sources of RE elements were analyzed.The main research findings are as follows:1.ICP-MS has many characteristics,such as high sensitivity,little interference,ultra-trace detection limit,good stability and rapid measurement of multi-element synchronization.The measurement results are accurate and reliable which is suitable for RE elements content detection in tea substitute.2.In 55 tea substitute samples,there are 39 samples of RE oxide less than 2mg/kg,accounting for 70.9%of the total amount of the sample.16 samples more than 2mg/kg,accounting for 29.1%;5 samples more than 5mg/kg in 16 samples,accounting for 9.09%.3.Among the 4 types of tea substitute,the leaves type gets the highest average RE oxide content,followed by flowers type,the last is fruits type,and mixed type between flowers and fruits.And as we can see from the results,the highest average RE elements content in flowers type is Herbaceous plant,woody plant takes the second place,and Vine plant is the lowest;Vine is slightly higher than Woody in fruits type;Woody is 1.8 times higher than Herbaceous in leaves type.RE oxide content in fruits type is lower overall,12 of the 13 samples of it are less than 2mg/kg.4.The same kind tea substitute with different origins has a certain different content of RE oxide.The varieties with smaller differences are:Florists Chrysanthemum,Chinese Wolfberry,Kuding Tea,Hawthorn and Mulberry Leaf.The varieties with difference about 2-3 times are:Dried Lemon,Slimming Fruit,Sweet Fruit,Ginkgo Leaf and Honeysuckle.The varieties with huge differences are:Snow Chrysanthemum,Fairy Fruit and Gynostemma.The above data shows that total amount of RE in tea substitute is greatly influenced by the environment of different origins.5.The content of RE elements in tea substitute has low food safety risk.The National Food Safety Standards of the current implementation canceled the content of RE elements in tea substitute requirements.At the same time,based on the method of risk assessment on human food safety,the percentages of RE(Exposures)consumed by human body through drinking different tea substitute are 0.57%,0.26%,0.97%,0.37%respectively,which accounts for ADI value of RE.According to the provisions of the CAC program manual of Food and Agriculture Organization of the United Nations on the formulation of pollutant limits,there is no limit standard if the exposures amount of tea substitute pollutants is less than 5%of ADI.6.From statistical correlation of test results,the correlation coefficient of flowers type and fruits type,flowers type and leaves type,fruits type and leaves type are 0.97,0.93 and 0.96 respectively,shows that the RE elements content ratio between these types of tea substitute is similar to each other.7.From the analysis of the test data shows that the average content of 3 kinds of RE in tea substitute are Ce(0.94 mg/kg),La(0.52 mg/kg)and Y(0.27mg/kg),the 3 kinds of RE elements in tea substitute exceeds the other RE elements,which is in accordance with the data of the content of the RE elements in the soil of our country.