Simultaneous determination of bromine and iodine species in dairy products by LC-ICP-MS

Tóm tắt

This study developed and optimized a liquid chromatography hyphenated with inductively coupled plasma mass spectrometry (LC-ICP-MS) method for the simultaneous determination of iodine (iodide and iodate) and bromine species (bromide and bromate) in dairy products. Samples were extracted with a 10 mM ammonium carbonate solution containing 0.5 mM Mg-EDTA, then analyzed by LC–ICP–MS using an anion-exchange column (Shodex NI-424, 5 µm × 4.6 mm × 150 mm) and a mobile phase of 50 mM ammonium carbonate containing 1% methanol (pH = 10). The limits of quantification (LOQs) for iodate, iodide, bromate, and bromide in liquid milk matrices were established at 1.10, 1.77, 8.50, and 12.2 µg/100g, respectively. The corresponding values for solid samples were found to be 5.50, 8.90, 42.5, and 61.0 µg/100g. The method repeatability ranged from 1.90% to 6.01%, with recoveries between 86.3% and 109.8%, meeting AOAC performance criteria. Analysis of 26 commercial milk samples from Hanoi showed no detectable iodate or bromate. Iodide concentrations were highest in powdered milk (13.5 – 203 µg/100g) and lowest in liquid milk (1.29–34.4 µg/100g). Bromide was detected in most products, with the highest levels in powdered milk (996– 2229 µg/100g), followed by liquid milk (5.60 – 397 µg/100g) and yogurt (259 – 383 µg/100g). The results confirm that LC-ICP-MS is a robust and reliable technique for the simultaneous determination of iodine and bromine species in dairy products, providing essential data for nutritional evaluation and food safety assessment.