Study On Detection Method Of Cd In Rice Based On EDXRF Technology

In the food structure of our country,the main food crops for urban and rural residents are rice.At the same time,the heavy metal content in rice is not only closely related to the quality of rice,but also closely related to human health.The Ministry of Land and Resources has also publicly stated that heavy metal pollution in China has resulted in annual grain production reduction of more than 10 million tons,annual heavy metal pollution of more than 1,200 tons of grain,and cumulative economic losses of 20 billion yuan[1].At present,the most common techniques for detecting heavy metals in food products are graphite furnace atomic absorption spectrometry,atomic fluorescence spectrometry,electrochemical analysis,etc.,but these are complicated and time-consuming methods.However,the acquisition and storage of rice is generally in the summer,and it is necessary to complete such a large workload in a short time[2],so it is very urgent to find an efficient and fast on-site rapid screening method for rice.Monitoring of heavy metals.Therefore,this study established a method for detecting cadmium in rice based on EDXRF technology,aiming to provide a reference for ensuring rapid and accurate detection and ensuring the safety of rice.The main work and progress are as follows:Firstly,the rice is pretreated,and the various parameters in the EDXRF rapid detection method for heavy metals in rice are optimized,including five indexes of rice particle size,detection time,tableting pressure,water content and rice thickness.The optimization results are: The rice has a particle size of140 mesh,a detection time of 180 s,a tableting pressure of 40 MPa,a water content of <5%,and a rice mass of 5g.This is the best experimental condition for the rapid detection of Cd in rice based on EDXRF.Secondly,the detection method of Cd in rice was established by optimized conditions,and the method was evaluated by four methods:precision,repeatability,stability and spike recovery.The EDXRF method has a relative standard deviation(RSD)of 0.11%,a reproducible RSD value of0.05%,a stable RSD value of 0.45%,and a spiked recovery of 114.8%.The newly established EDXRF method has good accuracy,repeatability and stability,and the recovery rate of the standard addition is high,which can meet the requirements of laboratory and rapid detection as a whole.Finally,a correlation analysis was performed on the two detection methods.The cadmium content of rice measured by the two methods was0.017 mg/kg and 0.014 mg/kg,respectively,and the results showed that the correlation between the EDXRF method and the graphite furnace atomic absorption spectrometry was good,which proved that the EDXRF method was accurate and credible.The rapid detection method for heavy metals used in this experiment can be applied to rapid screening,which can meet the requirements of rapid detection in the laboratory and on-site.It is expected to have a good application prospect in the detection of heavy metals in grain.