Serum iron determination using ferene triazine. 
The synthesis and characterisation of a new colorimetric reagent for iron, 3-(2-pyridyl)-5,6-bis(2-furyl)-1,2,4-triazine are described.  Peak assignments and chemical shifts of the high resolution 13C nmr spectrum are given.  The reagent forms a tris iron(II) complex with epsilon max of 32000 Lcm-1 mol-1 at 577 nm.  The results of precision, linearity and recovery studies for use of the reagent in direct serum iron determinations are reported.  Thiourea effectively suppresses copper interference for the serum iron determinations.  With the procedure used, the presence of hemolysed cells in the serum had no effect on serum iron levels recorded.