Abstract:
Cadmium is a heavy metal environmental pollutant, and excessive intake of cadmium will endanger human health. National standard detection method for cadmium in wheat is stable, reliable and sensitive, but the sample pretreatment operation is complicated, the cycle is long, and it is restricted by equipment, personnel and environment, so it is not suitable for grass-roots personnel to master and promote. Therefore, in order to meet the needs of daily food risk monitoring and on-site grain collection detection in basic grain depots, a simple, fast, accurate and reliable analysis method for the determination of cadmium content in wheat (flour) was established. The limits of detection and quantification of cadmium in blank samples were determined by six different types of X-ray fluorescent spectrometer. In order to verify and evaluate the accuracy and precision of the method, AAS and XRF were used to detect 4 groups of positive wheat (flour) samples from 12 laboratories. The results showed that the limits of detection and quantification were 0.0219-0.0340 mg/kg and 0.0303-0.0686 mg/kg, which could meet the standard requirements of the method. Paired
t-test was used for this method and GFAAS, and there was no significant difference between the two methods. Through verification and analysis among 12 laboratories, when the cadmium content of wheat (flour) was 0.054-0.414 mg/kg, the relationship between the method repeatability standard deviation
Sr and reproducibility standard deviation
SR and cadmium content
m was established, and the final value of the precision of the measurement method (expressed in mg/kg) was: standard deviation of repeatability
Sr = 0.031
m+ 0.002 and the standard deviation of reproducibility
SR = 0.026
m+ 0.003, all in line with relevant mathematical statistics requirements. Therefore, the process and parameters of this method are reasonable, the detection time is short, the detection efficiency is high, the sample pretreatment is simple, no reagent consumption, the detection cost is low, and the method is green and environmentally friendly, which can meet the current detection application requirements and can be widely promoted for the rapid detection of cadmium content in wheat (flour).