Method of rapid spectrophotometric determination of iron in dithionite extracts of soils

Amethod for the determination of dithionite iron for soil samples and fractions of the order of 20–25 mg with a spectrophotometric termination has been developed and optimized.Unlike the previously described methods, phenanthroline was used as a chromogen, which made it possible to simplify the analysis by eliminating the combustion stage.The procedure for processing samples with citrate-bicarbonate-dithionite extractant has been optimized.The repeatability and intra-laboratory reproducibility of the technique are investigated.Verification of the proposed methodology by comparison with the standard one showed good convergence of the results.