[Determination of toxic element concentrations in flour and cereal products by mass spectrometry with inductively coupled plasma]

Abstract

Systemic control and monitoring in the sphere of providing sanitary epidemiological welfare of population require routine procedures for determining toxic elements in variable foodstuffs. Their development is a pressing issue. Our research goal was to develop a procedure for determining concentrations of arsenic, cadmium, lead, mercury, aluminum and strontium in flour and cereal products by mass spectrometry with inductively coupled plasma. Material and methods. The most relevant calibration parameters for an Agilent 7900 mass spectrometer with octopole collision/ reaction cell and conditions for sample preparation by microwave digestion have been established; calibration characteristics and a range of determined concentrations have been identified. The limits of detections (LOD) and limits of quantification (LOQ) for 6 analyzed elements have been calculated. Results. Our procedure for determining mass concentrations of arsenic, cadmium, lead, mercury, aluminum and strontium in flour and cereal products by mass spectrometry with inductively coupled plasma has yielded the following results: when analyzing a sample weighing 0.5 g, we determine cadmium concentration within a range from 0.0008 to 70.0 mg/kg with inaccuracy from 14 to 25%; arsenic concentration within a range from 0.002 to 70 mg/kg with inaccuracy varying from 11 to 26%; mercury concentration from 0.003 to 7.0 mg/kg with inaccuracy from 15 to 25%; lead concentration from 0.01 to 70.0 mg/kg with inaccuracy from 12 to 26%; aluminum concentration from 0.2 to 70.0 mg/kg with inaccuracy from 13 to 20%; strontium concentration from 0.02 to 70 mg/kg with inaccuracy from 12 to 20%. The procedure was tested on samples of rice groats with the focus on the most popular brands. Thus, arsenic was detected in a concentration equal to 0.163 mg/kg in round-grain rice and 0.098 mg/kg in parboiled rice, which does not exceed the permissible level fixed for the element at 0.2 mg/kg. In all the analyzed samples, content of cadmium, lead and mercury did not exceed maximum permissible levels established by the Technical regulation of the Customs Union TR CU 021/2011 for flour and cereal products. These levels are 0.1 mg/kg for cadmium, 0.5 mg/kg for lead and 0.03 mg/kg for mercury. Conclusion. The developed procedure for determining toxic elements in flour, cereals and bakery products by using mass spectrometry with inductively coupled plasma gives an opportunity to determine such elements in quantities lower than permissible levels fixed for them in technical regulations and sanitary rules. The procedure expands the existing methodical instruments for control of food quality in the Russian Federation.

Keywords: bakery products; collision/reaction cell; flour and cereal products; mass spectrometry with inductively coupled plasma; rice; toxic elements.