Dimethylglyoxime

Chemical properties

Dimethylglyoxime is a white crystalline powder. Soluble in alcohol, ether, acetone and pyridine. Solubility in water 0.5g/l, insoluble in tolerate chloroform, toluene, xylene. It is one of the first selective organic reagents applied in analytical chemistry. It is an extraordinary sensitive and specific reagent for nickel. under appropriate conditions dimethylglyoxime is specific for nickel(II) and palladium(II), but it also forms coloured water-soluble complexes with iron(II), cobalt(II) and copper(II).

The Uses of Dimethylglyoxime

Dimethylglyoxime is specific for nickel(II) ions in ammoniacal solution if alkali tartrate is employed as masking agent to keep in solution the possibly interfering hydrolysing salts.

What are the applications of Application

Dimethylglyoxime is a chelating agent which forms complexes with metals such as copper, nickel, and palladium.

Reactions

Nickel cation reacts with dimethylglyoxime forms an insoluble red precipitate of nickel dimethylglyoxime.
Ni2+ + 2C4H8N2O2 → Ni(C4H7N2O2)2↓(red precipitate) + 2H+
Dimethylglyoxime reacts with ferrous sulphate and ammonium hydroxide forms a complex compound of iron and ammonium sulphate and water is formed.
FeSO4 + 2NH4OH + 2C4H8N2O2 → Fe(C4H7N2O2)2 + (NH4)2SO4 + 2H2O

General Description

Dimethylglyoxime (DMG) is a complexing ligand. Dimethylglyoxime forms a number of mixed ligand complexes with N-acetylglycine with metals such as VO(IV), Ni(II), Zn(II), Pd(II), Cd(II) and Pb(II). It is a useful reagent for the spectrophotometric determination of Co(II), Fe(II), Ni(II), Pd(II) and Re(VII).

Applications

Dimethylglyoxime is defined as a well-known ligand used in the analysis of nickel, forming an insoluble red complex with nickel known as Ni(DMGH)2. It provides a planar tetracoordinate nitrogen environment analogous to that found in the corrin ring of vitamin B12 and the porphyrin ring of heme systems.

Detection use

The dimethylglyoxime test (nickel spot test) and the cobalt spot test (based on disodium-1-nitroso-2-naphthol-3,6-disulfonate) can be used to detect nickel or cobalt released from metal objects and dermal exposure, thus aiding in avoidance of contact in sensitized patients.