Concentrations of selected trace elements in human milk and in infant formulas determined by magnetic sector field inductively coupled plasma-mass spectrometry

Magnetic sector field inductively coupled plasma-mass spectrometry (ICP-MS) was applied to the reliable determination of the 8 essential trace element s cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nicke l (Ni), selenium (Se), and vanadium (V) as well as the 7 nonessential and t oxic elements silver (Ag), aluminum (Al), arsenic (As), gold (Au), platinum (Pt), scandium (Sc), and titanum (Ti) in 27 transitory and mature human mi lk samples and in 4 selected infant formulas. This advanced instrumentation can separate spectral overlaps from the analyte signal hampering significa ntly the determination of many trace elements by conventional ICP-MS. Moreo ver, superior detection limits in the picogram per Liter range can be obtai ned with such magnetic sector field instruments. Therefore, this is the fir st study to report the concentrations of the elements Ag, Au, Pt, Se, Ti, a nd V in human milk and in infant formulas. Concentrations of Ag (median: 0. 41 mu g/L; range: < 0.13-42 mu g/L) and Au (median: 0.29 mu g/L; range 0.10 -2.06 mu g/L) showed large variations in human milk that might be associate d with dental fillings and jewelry. Pt concentrations were very low with mo st of the samples below the method detection limit of 0.01 mu g/L. Human mi lk concentrations of Co (median: 0.19 mu g/L), Fe (380 mu g /L), Mn (6.3 mu g/L), Ni (0.79 mu g/L), and Se (17 mu g/L) were at the low end of the corr esponding reference ranges. Concentrations of Cr (24.3 mu g/L) in human mil k were five times higher than the high end of the reference range. For Al ( 67 mu g/L), As (6.7 mu g/L), and V (0.18 mu g/L), most of the samples had c oncentrations well within the reference ranges. All elemental concentration s in infant formulas (except for Cr) were approximately one order of magnit ude higher than in human milk.