Photoelectric Colorimetry

Microdetermination of Chromium with 1,5-Diphenylcarbohydrazide

“…An average molar absorbancy index of 4.17 X 104 at 546 µ, with a mean deviation of ±0.04 X 104, has been obtained in 21 experiments using fresh solutions of a good grade of 1,5-diphenylcarbohydrazide, but with many different conditions of the other variables. This value is in excellent agreement with the result of Urone and Anders (21) (Table I) and is in good agreement with the results of Rowiand (16) and Saltzman (17).…”

Capillary Absorption Cells in Spectrophotometry

“…The method was tested in the analysis of iron by the o-phenanthroline method (5,16), chromium by the diphenylcarbazide method (12,14), manganese measured as permanganate (19), and phosphate (1) and silicon (2), both measured as molybdenum blue. The sample size corresponding to 90% transmission, which is still within the quantitatively determinable range of these procedures, is shown in Table I.…”

Sampling and analysis considerations for the determination of hexavalent chromium in workplace airThis article was prepared by governmental employees of the United States of America and the United Kingdom as part of their official duties, and legally may not be copyrighted in the USA or the UK.

“…The reaction is highly specific for Cr(VI) (vs. Cr[III]), although several other metal species are also known to react with DPC, i.e., Cu(II), Fe(III), Hg(II), Mo(VI), and V(V). 35 The acid extraction-DPC spectrophotometric technique is satisfactory if there are no interferences from substances which can: (a) react with Cr(VI) and change its valence state; and/or (b) react with DPC and thereby compete with Cr(VI) for the colorimetric reagent. For many applications, e.g., the determination of Cr(VI) in welding fumes, the direct DPC procedure is not applicable, since there is a high probability that redox reactions will lead to the loss of Cr(VI) during analysis.…”