Determination of strontium content in different dairy products by inductively coupled plasma mass spectrometry

An analytical method for determining the strontium content in different dairy products was established through inductively coupled plasma mass spectrometry (ICP-MS). After microwave digestion treatment of the samples, the content of strontium element was determined by ICP-MS method with 88Sr and internal standard 72Ge and the helium flow rate was 4.0 ml/min. The results indicated that strontium exhibited a good linear relationship within the range of 0-500 ng/ml, with a correlation coefficient (R²) greater than 0.999. The detection limit (LOD) of the method was 2.21 μg/kg, and the quantification limit (LOQ) was 6.27 μg/kg. The spiked recovery rates in four dairy products ranged from 81.5% to 109.0%, and the relative standard deviation (RSD) of the precision experiments was 0.77%-3.73%. In the actual determination of milk powder samples, the detected value of strontium element was 2.03 mg/kg, which had no significant difference from the median value (2.08 mg/kg) of strontium element content in standard milk powder samples containing strontium (P>0.05). It was indicated that the method was simple and rapid, had a wide linear range, low interference and high sensitivity, and could be used for the determination of strontium element in different dairy products.