A rapid method for the spectrophotometric determination of iron in silicate rocks

A sensitive and selective spectrophotometric method for the rapid determination of iron in silicate rocks has been devised using the reagent, 2,3-dihydroxynaphthalene. The molar absorptivity at 452 nm and Sandell's sensitivity of the method are 1.1x10(4) l mol(-1) cm(-1) and 0.005 mu g cm(-2), respectively. The Beer's law is obeyed over a wide range from 0.04 to 10 mu g ml(-1) of iron. The selectivity of the method has been improved by extraction spectrophotometry. The method has been applied to a number of diverse silicate rock samples and results obtained are found to be favourably comparable with those obtained from 1,10-phenanthroline and iron metods. The method is better than that of the tiron in terms of sensitivity and selectivity. The reagent used here is a better variant of tiron for iron determination.