Speeding the classical DMG method for nickel analysis using thermometric titration gives results in less than three minutes
The gravimetric determination of nickel using dimethylglyoxime (DMG) is still the classical procedure used in referee analysis today.
However, it does require quite some skill, and it is slow - very slow.
Modern laboratories require a high level of productivity from their analysts, and instead of a procedure that takes hours to get a result, we now have a titration that takes less than three minutes.
Multitrator recorded a standard deviation of 0.02% nickel and a CV (%RSD) of 0.1 during a test run.
The thermistor reportedly isn't troubled by the crimson soup it's immersed in, and sharp endpoints were seen.
A downside? Yes, cobalt interferes, as cobalt forms a soluble complex with DMG and titrates along with nickel if they are in the same solution.
However, a rival potentiometric titration using cyanide as titrant also suffers from cobalt interference. For applications in the nickel industry, where a total Ni+Co level is satisfactory for process control purposes, you'd choose the thermometric DMG method over the potentiometric cyanide procedure any day, says Multitrator.
Potential interferences such as aluminium, iron and chromium can be taken care of by complexing with tartrate or citrate.
Multitrator thinks that the new thermometric method has great potential in analysing nickel in a range of applications, and has the potential to supplant the standard gravimetric procedure in a number of instances.
