The laboratory of the Department of Arctic Environment has the most modern atomic absorption equipment for determination of trace elements in organic and inorganic samples. It is accredited after the ISO 17025 standard by DANAK with the registration number 435. The accreditation covers the elements:

Cd, Pb, Zn, Cu, Li, Ni, As, Hg, Cr and Se.

See accreditation no. 435 at the Danak homepage (in Danish).

The laboratory can analyse other elements outside the scope of the accreditation.

All analyses are performed by three atomic absorption (AAS) methods: Graphite furnace AAS, Flame AAS and Flow injection analyse.

During the analyses a few drops of sample are heated to temperatures up to 2600  degrees C in the graphite furnace. Simultaneously an alternating magnetic field is applied over the furnace, and the absorption of a light beam of an element specific wavelength is measured.

A close-up picture of the graphite furnace and the sample changer.

In this method a nebula of the sample solution is sucked up into a flame. Simultaneously the absorption of element specific light in the flame is measured.

The flame atomic absorption spectrometer.

This method (FIAS) is mainly used for mercury analyses, but in combination with a flame atomic absorption spectrometer also selenium and arsenic can be measured. The method uses a chemical reaction between sodium boro hydride and the analyte, which converts the mercury to elemental mercury and selenium and arsenic to hydrides.

Left: The flow Injection Equipment. Right: The flame atomic absorption spectrometer.

Before analyses the samples have to be dissolved. This is done in a pressurised Teflon container at elevated temperature. Biological samples and samples for mercury analyses are dissolved in nitric acid. Inorganic solids like sediments are dissolved in a mixture of hydrofluoric acid and nitric acid.