Abstract:

Yak milk samples were freeze dried in a vacuum chamber and digested using microwave, and the digestion solution was directly injected into inductively coupled plasma-mass spectrometry (ICP-MS) for quantitative determination of trace elements by external standard method. The relative standard deviations of precision of this method were between 1.80% and 4.50%, and the spiked recoveries ranged from 95.61% to 102.90%. Yak milk contained a variety of trace elements which exist in the human body, and the average contents of the trace elements in yak milk were (calculated on dry matter basis): Cu 0.340, Zn 50.6, Fe 16.12, Mn 0.843, Mo 0.170, Co 0.023, Ni 0.522, Ti 0.001, V 0.105, Li 0.056, Be 0.003, Bi 0.029, Pb 0.305, and Cd 0.014μg/g, respectively.

Key words: yak milk, microwave digestion, ICP-MS, freeze-drying, trace elements