Measurement of trace elements in proteins extracted from liver by size exclusion chromatography-inductively coupled plasma-mass spectrometry with a magnetic sector mass spectrometer

Proteins are extracted from liver into aqueous buffer at pH 7 and separated by size exclusion chromatography (SEC). Inductively coupled plasma mass sp ectrometry (ICP-MS) with a magnetic sector mass spectrometer is used to ide ntify those protein fractions that contain Cu, Zn, Mn, Fe, Cd, S, P, Mo, Co , Ca, or Mg. The experimental setup provides very high sensitivity. Measure ments at medium spectral resolution remove polyatomic interferences for som e difficult elements like Fe, S, and P. Some elements are found in differen t molecular weight proteins; for example, cadmium binds to four different p rotein fractions (>400 kDa, 70 kDa, and metallothionein). Other elements li ke Mo, Ca, and Mg are present only in low-molecular-weight proteins or othe r small molecules. (C) 2001 Academic Press.