Fractionation of Extractable Petroleum Hydrocarbons from Soil Using ISOLUTE® EPH SPE Columns

Richard Calverley, Geoff Davies, and Helen Lodder, Biotage GB Ltd

ISOLUTE EPH columns have been developed to fractionate pentane or hexane based soil extracts into aliphatic and aromatic hydrocarbon fractions (C8–C40 aliphatics, C10–C22 aromatics). The columns have been designed to eliminate the common problem of aromatic breakthrough into the aliphatic fraction. The approach is broadly based on procedures published by the Massachusetts Department of Environmental Protection (MADEP) and the TPH Criteria Working Group (TPHCWG). The manual ISOLUTE EPH column described in this application note uses a similar fractionation column sorbent mass to these published methods. An automated ISOLUTE EPH product and associated methodology is also available to provide reliable high throughput fractionation with substantial reductions in solvent consumption and costs.

Results

Figure 1 highlights the high absolute recoveries of both the aromatic and aliphatic fractions (>90%), based on fractionation of 20 ppm each of 16 aromatic and 17 aliphatic component standard in hexane. Figure 2 represents the post-fractionation aliphatic chromatogram. There is no trace of naphthalene present, a good indicator of an efficient aliphatic/aromatic split.

Figure 1

Conclusions

A robust approach to the fractionation of EPH in soil extracts has been developed which provides an effective split of the aliphatic and aromatic components. Optimised sorbent activity provides aliphatic fractions free of the lower molecular weight aromatic hydrocarbons such as naphthalene.

Figure 2

The manual EPH fractionation procedure can be automated using an optimised ISOLUTE EPH column with reduced sorbent mass. Automation provides the opportunity to reduce solvent costs, minimise evaporation requirements, and to enhance productivity.

For details of both manual and automated EPH fractionation procedures, please visit www.biotage.com or email product_info@biotage.com.

ISOLUTE is a registered trademark of Biotage.

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