Accurate Quantification of Pure Thiacloprid with Mass Balance and Quantitative H-NMR

Thiacloprid is the first-generation neonicotinoid insecticide, which is widely used in modern agriculture. Reference materials are essential for sound measurement and traceability of results in chemical analysis. Pure thiacloprid was comprehensively assessed by two orthonormal methods: mass balance (MB) and quantitative nuclear magnetic resonance spectroscopy (qNMR). From MB, its mass fraction value was 998.4 mg/g with the subtraction of structurally related impurities (99.87%), inorganic impurities (0.006 mg/g), water (0.33 mg/g), and volatile organic solvent (0 mg/g). To guarantee sufficient separation of structurally related purity, peak purity of thiacloprid was evaluated by five points of UV spectra. From the qNMR of hydrogen, its mass fraction value was 995.7 mg/g which was traced to the internal standard (methyl sulfone). Finally, the certified value was assigned to 997 mg/g, together with an expanded uncertainty of 3 mg/g ( k  = 2). This high-purity thiacloprid can be applied to routine monitoring in agriculture and the food fields.