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Development of a chemiluminescent enzyme immunoassay to detect cadmium in cereal samples
- Xiao, Zhi-Li, Tian, Wei, Xu, Zhen-Lin, Sun, Yuan-Ming
- Food and agricultural immunology 2018 v.29 no.1 pp. 1184-1196
- brown rice, cadmium, calcium, chemiluminescence, copper, corn, enzyme immunoassays, glutinous rice, gold, inhibitory concentration 50, iron, lead, magnesium, manganese, mercury, metal ions, peroxidase, silver, wheat, zinc
- In this study, we develop a sensitive indirect competitive chemiluminescent enzyme immunoassay (ic-CLEIA) to detect cadmium (Cd) in cereals. A luminol-hydrogen peroxide chemiluminescence system catalysed by horseradish peroxidase (HRP) was used as the signal detecting system. The method showed a half-maximal inhibition concentration (IC₅₀) of 0.5 ng/mL and a limit of determination (LOD) of 0.06 ng/mL. The assay indicated an effective linear range from 0.16 to 1.56 ng/mL. There were no obvious cross-reactivities with other metal ions, including Hg²⁺, Pb²⁺, As²⁺, Ag⁺, Fe³⁺, Cu²⁺, Cr²⁺, Au³⁺, Ca²⁺, Mg²⁺, Mn²⁺ and Zn²⁺. Recovery rates ranged from 79.2% to 120.0% for rice, maize, wheat, brown rice and glutinous rice samples. Twenty-five practical cereal samples were analysed, and the comparative analysis of the results showed a strong correlation (r = 0.984) between the CLEIA and the GFAAS methods. The results indicated that the ic-CLEIA developed was acceptable to screen for cadmium in cereal samples.