Research on the Determination of Cadmium in Grain by Rapid Digestion-Standard Addition

Abstract

Rapid digestion-standard addition based on graphite furnace atomic absorption spectrometry(GFAAS) for determining cadmium in grain of four kinds of matrix (brown rice, corn, wheat and rice) is established, by studying on digestion conditions, optimizing the proportion of sample and nitric acid, and using digested sample to prepare standard solution. The results show that the correlation coefficients are 0.995 to 0.999. The detection limit of method is 0.003 mg/kg. The relative error between the test result and the standard value is –3.8% to –1.1%. The standard recoveries of cadmium in low, medium and high gradient are 99.1% to 103.4%, and the RSD values of the standard substances and real samples are 1.2% to 2.7%.Compared with the results of microwave digestion method, the detection values of cadmium have no significant difference (P>0.05). The method have shown advantages in terms of accuracy and precision, and it is a rapid and accurate method to calculate cadmium in large quantities of grain samples.

Keywords

• gfaas
• rapid digestion
• standard addition
• grain
• cadmium