Determination of the contents of inorganic elements in bromelain by microwave digestion-inductively coupled plasma mass spectrometry

A method was established for determining 25 inorganic elements in bromelain by microwave digestion- inductively coupled plasma mass spectrometry ( ICP- MS) . Internal standard solution online was used to correct matrix effect and signal drift.Interference equation was used to correct the contents of Co and Ni.CCT was used to determinate Se.The recovery percentage ranged from 82.2% to 113.0%.The RSD ranged from 0.55% to 4.94%. It could be concluded that the method could be applied to determine 25 inorganic elements in bromelain. The analysis results of milk powder standard samples were in the range of standard value. It showed that essential elements of body were rich in bromelain; the contents ( mg /kg) of harmful elements Pb, Cd, Cr, As were 0.75, 0.035, 7.2, 2.4mg /kg respectively and Hg was not detected, which could ensure the safety of the finally product. The contents ( mg /kg) of harmful elements Mg, Mn, Ca, Zn, Fe and Cu were 150, 53, 1700, 4.1, 1000, 3.2mg /kg respectively in bromelain. The content of Fe was higher than 20mg /kg. Therefore it is in urgent to reduce its containment by the optimizing of process. The determination results supplied the reference for scientific use of bromelain.