Nickel dimethylglyoximate equilibrium solution

Reagent Nickel dimethylglyoximate equilibrium solution is prepared by dissolving 2.3 g hydrated NiS04 in 300 ml water with 2.8 g dimethylgly-oxime dissolved in 300 ml ethanol. The suspension is allowed to stand for 30 minutes and then filtered. The filtrate, which constitutes the reagent solution, will keep for several weeks if stored in stoppered bottles. 

Procedure. A drop of a 10 % solution of the sample is taken to dryness in a micro crucible. The residue is treated with a drop of nickel dimethylglyoxime equilibrium solution (for preparation, see page 77). Red nickel dimethylglyoxime appears if monochromate is present. A blank on a pure bichromate solution is recommended when small amounts of monochromate are suspected. 

The reaction with nickel dimethylglyoxime equilibrium solution (see page 77) can be apphed with excellent results for the detection of alkaline earths and alkalis in ashes. 

When a neutral solution of the nickel salt of a mineral acid is treated with excess dimethylglyoxime, there is incomplete precipitation of the red Ni-dimethylglyoximate. The clear filtrate is a saturated solution of this inner complex salt (compare page 77) in which the following equilibrium has been established ... 

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