ICP-OES

ICP-OES makes use of the fact that the atoms of elements can take up energy from an Inductively Coupled Plasma (ICP). They are thereby excited, and fall back into their ground state again emitting a characteristic radiation.

The identification of this radiation permits the qualitative analysis of a sample. A quantitative determination takes place on the basis of the proportionality of radiation intensity and element concentration in calibration and analysis samples.

In ICP-OES analysis, the liquid sample is introduced into the core of inductively coupled argon plasma, which generates temperature of approximately 8000°C. At this temperature all elements become thermally excited and emit light at their characteristic wavelengths.

This light is collected by the spectrometer and passes through a diffraction grating that serves to resolve the light into a spectrum of its constituent wavelengths.

The spectrum emitted is transferred into a spectrometer where it is decomposed into the individual wavelengths and evaluated.

Most of the periodic table (with the exceptions of H, O, N, F, Cl) can be measured using ICP-OES. Concentrations from major to parts per million (ppm) or in many cases parts per billion (ppb) in solution can be measured.

Quantitative analysis involves calibrating the instrument with a series of appropriate solution standards and then measuring signals from the samples of interest.

The ICP-OES is currently used by CERE for:

• Cation Exchange Capacity (CEC)
• Analysis of fluid produced after flooding tests

Publications
Surface charge of calcite and its influence on the electrical conductivity in chalk

Excess conductivity of North Sea chalk and its influence on cementation exponent and saturation prediction

Alam, M.M. and Fabricius, I.L., 2010, NMR as a Tool for Estimation of Excess Conductivity in Chalk.

Petrophysics of shale intervals in the Skjold Field, Danish North Sea