Multi-Response Optimization and Validation of an Eco-Efficient Microwave-Assisted Digestion Method for Determination of Pb, As, Cd, and Hg in Rice by ICP-MS

Rice is a significant dietary source of toxic elements like Pb, Cd, As, and Hg, which accumulate in grains from contaminated soil and water. Conventional microwave-assisted digestion methods commonly employ concentrated acids, resulting in higher reagent consumption, hazardous waste generation, and environmental impact, whereas several reported dilute-acid methods require expensive specialized hardware and lack systematic optimization. To meet modern regulatory standards, an eco-efficient microwave-assisted digestion method using dilute HNO۳ and H۲O۲ was developed via multi-response optimization coupled with response surface methodology, and validated against strict EU regulatory standards, with its environmental sustainability assessment. The proposed method achieved high digestion efficiency (>۹۵%) with low RCC (۲%) using ۳.۶ mol L⁻¹ HNO۳ and ۱ mL ۳۰% H۲O۲. It demonstrated excellent analytical performance with good recoveries (۹۸.۵–۱۰۵.۱%), robust precision (HorRat<۲), and low detection and quantification limits, confirming suitability for official control. Applicability to rice samples from Delhi-NCR revealed contamination levels in the order Hg>As>Pb>Cd. The developed sustainable, regulatory-compliant approach provides good analytical performance while reducing reagent use, energy use, and waste, making it appropriate for high-throughput industrial and regulatory food safety laboratories.

کلیدواژه ها:

rice ، Microwave-assisted digestion ، multi-response optimization ، Method Validation ، ICP-MS