The concentration of free Cr (VI) ions in the effluent was determined with 1, 5-diphenyl carbazide
(DPC) in acidic solution spectrophotometrically (Elico SL 171) at l max 535 nm.
The reaction mixture was centrifuged and the concentration of the residual Cr(VI) was determined using the diphenyl carbazide
spectrophotometry method [29, 30] at the wavelength of 540 nm.
Quantification of LPS was done by the semi- carbazide
method of Batley et al.
The application describes the determination of hexavalent chromium using Metrohm's newly released 887 UV/VIS detector after post column reaction with diphenyl carbazide
in an 886 professional reactor.
Inhibition of corrosion of zinc in hydrochloric acid by some carbazide
derivatives has also been reported.
The treating solutions were analyzed for pH by meter and initial hexavalent chromium concentration by the diphenyl carbazide
method (Coggins and Hiscocks 1987) using a Shimatzu UV 160 spectrophotometer.
In each flask, 2ml of diphenyl carbazide
was then added and the flasks were kept for half an hour in dark.
The 1,5-diphenyl carbazide
from Merck were directly used for chromium detection.
In an attempt to prepare the thio- and semi- carbazide
derivatives 37-41 the carbonyl compounds 4a and 4d were treated with thio- and semi- carbazide
in ethanol under acidic conditions .
Thio- carbohydrazide H2NNHC(S)NHNH2 (abbreviated here as tch), the next higher homologue of thiosemi- carbazide
, typically acts as a neutral bidentate ligand coordinating to a metal through the sulfur atom and one of the terminal nitrogen atoms, forming five- membered chelate rings .