Determination of small amounts of nickel in organic matter by atomic-absorption spectrometry

Abstract

The method for the determination of nickel in organic matter is based on the atomic-absorption procedure already shown to be applicable to the determination of lead; both nickel and lead can therefore be determined on the same analytical sample. Organic matter is destroyed by wet oxidation in the presence of sulphuric acid. After dilution, the nickel (and lead) are recovered from the aqueous acid solution by extraction of the complexes formed with ammonium tetramethylenedithiocarbamate complexes into 4-methylpentan-2-one. The nickel content is determined by aspirating the extract into an air-acetylene flame, measuring the atomic absorption at 232.0 nm and comparing the resulting signal with a calibration graph prepared by submitting standard nickel solutions to an identical procedure. It is stressed that practice in sample preparation must be thorough before results can be reliable.