Essential serum trace metals

Studies of serum iron determination have been described using sensitive color reagents of high molar absorptivities. Each selective reaction for iron is strengthened by means of complexing molecules which eliminate trace metal interferences. One ligand. 4-(2-pyridylazo)-resorcinol, exhibits two sensitive peaks, either of which can be used to determine iron quantitatively if an interference is present at one wavelength, or to qualitatively help ensure by ratio measurement that iron is the only metal determined. The second ligand, 2,4-bis(5,6-diphenyl-1,2,4-triazin3-yl) pyridinetetrasulfonic acid, is not only sensitive but has the capability of measuring iron, copper, or both by a judicious choice of selective conditions. Each compound has a useful potential in either discrete sampling or on-stream automation.