Purity assessment of thiamethoxam using mass balance and quantitative nuclear magnetic resonance

Thiamethoxam (TMX) belongs to the second-generation neonicotinoid pesticide, which is among the most common residual in food commodities. To guarantee accurate quantification and traceability of results in food samples, certified reference materials (CRMs) are indispensable benchmark. TMX was characterized and its purity value was assessed by two independent measurement methods including mass balance (MB) and quantitative nuclear magnetic resonance spectroscopy (qNMR). Its mass fraction was 997.0 mg/g and 991.7 mg/g in MB and qNMR, respectively. Eventually, a purity of 994 mg/g with standard uncertainty of 3 mg/g ( k  = 2) was assigned to TMX.