BLT Stages

Samenvatting bachelorproef 2013-2014: Validation of a CMA-method for determination of biogenic or petrogene orgin of mineral oil in fixed samples on the basis of GC-MS

The purpose of this internship in the laboratory Eurofins is validating a CMA (Compendium for the sampling and analysis) method. The number of this CMA method is CMA/3/R.4 and has as title: "determination of the biogenic/petrogenic origin of mineral oil pollution in soil samples ".

The analyzed samples are sludge samples and bottom improving resources samples. The customer decided which samples needs to be analyzed.

For this analysis in the lab Eurofins at Nazareth, two different matrices were analyzed with two extractions: namely Soxhlet extraction used on sludge samples and saponification on bottom improving resources samples. Soxhlet is a solid/liquid extraction using a solvent to extract the solvable component out of the sludge. Saponification is a chemical process where oils and fats are sedimentation to glycerin and fat acid.

The next phase that is applied in this CMA method is a purification of the extracts. This purification is based on two sequential methods. The first step is purification with Florisil where biogenic and polar organic compounds will be removed from the extract. The second step is purification with activated silica gel where the polar hydrocarbons and aromatic components from the extract will be removed.

The purified samples can be measured using gas chromatography coupled on mass spectrometry (GC-MS). When the extract is measured with the GC-MS unit, the type of pollution is determined on the basis of three calibration curves and a decision table.

When the extract is biogenic, the sample is spiked with pure RIVM oil (National Institute for public health and Environmental Hygiene). This is done to check if the method is suitable for the determination of petrogene oil.

All the sludge samples from the Soxhlet extraction are petrogenic. This sample can’t be spiked. Some improver samples from the saponification extraction are biogenic or a mixture of petrogene and biogenic oil. The biogenic samples where spiked with RIVM oil and analyzed. After spiking the extract is petrogenic.

As conclusion, it can be said that the CMA-method is validated and introduced in the lab.