title: Assessment of homogeneity and minimum sample mass for cadmium analysis in powdered certified reference materials and real rice samples by solid sampling electrothermal vaporization atomic fluorescence spectrometry.
abstract: To optimize analytical quality controls of solid sampling electrothermal vaporization atomic fluorescence spectrometry (SS-ETV-AFS), the homogeneity (H(E)) of rice samples and their minimum sample mass (M) for cadmium analysis were evaluated using three certified reference materials (CRMs) and real rice samples. The effects of different grinding degrees (particle sizes <0.85, <0.25, <0.15, and >1 mm) on H(E) and M of real rice samples were also investigated. The calculated M values of three CRMs by the Pauwels equation were 2.19, 19.76, and 3.79 mg. The well-ground real rice samples (particle size <0.25 mm) demonstrated good homogeneity, and the M values were 3.48-4.27 mg. On the basis of these results, the Cd concentrations measured by the proposed method were compared with the results by microwave digestion graphite furnace atomic absorption spectrometry with a 0.5 g sample mass. There was no significant difference between these two methods, which meant that SS-ETV-AFS could be used to accurately detect Cd in rice with several milligrams of samples instead of the certified value (200 mg) or the recommended mass (200-500 mg) of the methods of the Association of Official Analytical Chemists.
authors.affiliation: Institute of Quality Standard and Testing Technology for Agri-products, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Xuefei
authors.initials: X
authors.lastname: Mao
authors.forename: Jixin
authors.initials: J
authors.lastname: Liu
authors.forename: Yatao
authors.initials: Y
authors.lastname: Huang
authors.forename: Li
authors.initials: L
authors.lastname: Feng
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhang
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Tang
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Qian
authors.forename: Min
authors.initials: M
authors.lastname: Wang
mesh_terms: D002104:Cadmium / Q000032:analysis* / Q000592:standards*; D012275:Oryza / Q000737:chemistry*; D012015:Reference Standards; D012639:Seeds / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013054:Spectrophotometry, Atomic / Q000379:methods*
chemical_list: D002104:Cadmium