Abstract: A method for simultaneous and quantitative determination of 10 elements including K, Ca, Na, Mg, P, Cu, Mn, Zn, Fe and Se in breast milk was established by inductively coupled-plasma mass spectrometry (ICP-MS). Samples were digested by using a mixture of HNO3 and H2O2 in a closed high pressure vessel before detection by ICP-MS. The mass spectral interferences caused by polyatomic ions were effectively eliminated by using a dynamic reaction cell. The element Rh was used as an internal standard element to correct the matrix effect and signal drift. The external standard calibration method was used for quantification, and relative standard deviation (RSD) was used to examine the method reproducibility. The accuracy of this method was evaluated by using standard reference materials. The correlation coefficients of the linear regression equations for the 10 elements were all above 0.999 0, and the recoveries ranged from 80.00% to 118.19%. The measured values for standard reference materials of milk powder (GBW10017) and defatted milk powder (GBW08509) were in agreement with the certified values, with RSDs below 10.0%. These results showed that this method was precise, accurate and suitable for the determination of mineral elements in massive breast milk samples.

Key words: breast milk; mineral elements; inductively coupled-plasma mass spectrometry; sealed high pressure digestion