X-ray fluorescence spectrometric determination of the metal content of the extracellular hemoglobin of Tubifex tubifex.

X-ray fluorescence spectrometric analysis of Tubifex hemoglobin, using the energy-dispersive and wavelength-dispersive spectrometers, demonstrated that in addition to Fe, Ca and small amounts of Zn, Cu and Pb were also present. Assuming that Tubifex hemoglobin contains 160 atoms of Fe per molecular weight of 3.9 10(6), the molar ratios of Fe:Ca:Zn:Cu:Pb were calculated to be 160:70:2:8: 2. The iron content of the hemoglobin was also determined spectrophotometrically using the formation of Fe(II)-1,10-phenanthroline and Fe(II)-4-(2-pyridylazo)-resorcinol complexes: it was found to be 0.240+/-0.010% by weight and was unaffected by prior dialysis against 10 mM EDTA solution at neutral pH. Thus, it is unlikely that Tubifex hemoglobin contains any non-heme iron.