Nassar et al. (2025) develop and validate a spectrophotometric method for the determination of cadmium(II) (Cd2+) using a chromogenic reagent. The method provides LOD and LOQ data for Cd in reagent-grade and potentially environmental matrices.
Key numbers
LOD: 0.245 µg/mL (245 µg/L = 245 ppb) in the measured solution.
LOQ: 0.817 µg/mL (817 µg/L = 817 ppb) in the measured solution.
These values are high relative to food matrix requirements: EU maximum levels for Cd in most foods range from 0.05 to 1 mg/kg (50 to 1000 ppb wet weight), and analytical methods for regulatory compliance need LODs well below the lowest maximum level. The spectrophotometric LOD of 245 ppb (in solution after extraction/dilution) is at the borderline of food compliance applications and would be adequate only for the highest-Cd food matrices (kidneys, cocoa, offal) not for infant formula or cereals where Cd MRLs are 0.05–0.10 mg/kg.
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Methods (brief)
UV-vis spectrophotometry with chromogenic complexation reagent for Cd2+. Method validation per standard protocols (linearity, accuracy, precision, LOD, LOQ). Spectrophotometric methods for Cd are generally less sensitive than ICP-MS (LOD typically 0.001–0.01 µg/L) but offer lower instrument cost and simpler operation.
Implications
Testing: The LOD of 245 ppb in solution is adequate for industrial process water or heavily contaminated environmental samples but would require significant preconcentration (e.g., solid-phase extraction) before it could be applied to food matrices near regulatory limits. ICP-MS remains the preferred method for food Cd analysis at sub-50 ppb levels.