Section 13
Chapter 12,286

Manganese speciation in human milk using size exclusion chromatography combined with strong anion exchange chromatography and inductively coupled plasma mass spectrometry detection

Michalke, B.; Schramel, P.

Journal of Analytical Atomic Spectrometry 19(1): 121-128


ISSN/ISBN: 0267-9477
DOI: 10.1039/b304177h
Accession: 012285645

Human milk was investigated concerning Mn speciation. In a first step subfractions were produced by centrifugation and analysed for manganese by inductively coupled plasma atomic emission spectrometry (ICP-AES). It turned out that Mn concentrations were approximately 3 mug L-1 (human milk), 2.85 mug L-1 in the defatted fraction, 0.25 mug L-1 in the pellet fraction and 2.6 mug L-1 in the low molecular weight (LMW)-supernatant fraction. The defatted fraction was investigated further by on-line coupling of size exclusion chromatography (SEC) to inductively coupled plasma mass spectrometry (ICP-MS). The columns had either a separation range between 10 and 150 kDa or 100-2000 Da. It is shown that manganese was found predominantly in the LMW fraction. The mainpeak in LMW-SEC eluted at 95 min, which was assigned to masses around-300 Da due to the mass calibration of the TSK column. Subsequent investigations analysed respective SEC-fractions by strong anion exchange (SAX)-ICP-MS and compared chromatograms with those of Mn standard compounds. Inorganic manganese species and Mn-citrate complex were identified. Some further Mn compounds of low concentration were seen, but could not be assigned to specific standard compounds.

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