A common impurity is phenyl-semicarbazide which can be removed by chromatography: ~8g in H2O is placed on a column (polyamide 6 powder, Macherey-Nagel-GmbH-Germany, washed several times with MeOH), eluted with H2O/MeOH/AcOH (1:3:0.04) at 7-8 drops/second, then eluted with the same solvent mixture but diluted 5 fold with H2O. The purification is followed by UV light at 280nm. The effluent is evaporated to dryness in vacuo at ~28o. [chromatography, IR & UV: Willems et al. Anal Chim Acta 51 544 1970]. Recrystallise it from EtOH by adding CCl4 to induce crystallisation, or AcOH to give a white crystalline powder which turns pink in air. It is air and light sensitive and should be stored in the dark under N2. [Beilstein 15 H 292, 15 IV 182.]
1,5-Diphenylcarbazideis a carbazide derivative used in the colorimteric determination of chromium as well as in the detection of cadmium, mercury, magnesium and aldehydes.
white crystals or powder
As indicator in titrating Fe; for the colorimetric determination of Cr, detection of Cd, Hg, Mg, aldehydes, emetine.