Rapid and simultaneous detection of lead and cadmium in foods using solid sampling electrothermal vaporization...

This work constructed an innovative rapid multi-elemental analyzer of Pb and Cd using solid sampling electrothermal vaporization (ETV) with a composite trap based on the principle of gas phase enrichment (GPE). A SiO₂-MgO-SiO₂ sandwich-structured GPE unit was first fabricated to enable simultaneous capture and rapid thermal release of Pb and Cd. Mechanism studies demonstrated that temperature drives the distribution of Pb and Cd in GPE unit; lower temperature favors accumulation at the lower layer, while higher temperature promotes upper migration and may thus reduce trapping efficiency. Under optimized conditions, limits of detection (LODs) of 0.4-0.5 ng/g were achieved in 100 mg sample size. The linearity (R²>0.999) and the recoveries (82-117 %) indicate excellent analytical precision and accuracy without requiring sample digestion. Rapid detection of Pb and Cd in various food matrices was accomplished with ∼3 min. Thus, the proposed method is simple, green and robust, making it suitable for rapid monitoring of heavy metals in food.