Davies et al.

Automated Fractionation of Extractable Petroleum Hydrocarbons from Soil

Geoff  Davies, Richard Calverley, Helen Lodder, Steve Jordan, Gary Dowthwaite
Biotage GB Limited, Distribution Way, Dyffryn Business Park, Ystrad Mynach,
Mid Glamorgan, CF82 7TS, UK.

With the recent oil spill in the Gulf of Mexico, much focus is on the analysis of hydrocarbons from a variety of matrices.  The need for cost-effective and accurate methods will coincide greatly with the need for state-of-the-industry sample preparation.  Here we improve the methodology for the analysis of Extractable Petroleum Hydrocarbons (EPHs) from soil utilizing the RapidTrace, an automated SPE system. 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). Consisting of a proprietary blend of silica/alumina, they are optimized to achieve a clean fractionation  without  the common problem of aromatic breakthrough into the aliphatic fraction. The approach is broadly based on procedures published by the Massachusetts Dept of Environmental Protection (MADEP) and the TPH Criteria Working Group (TPHCWG). The manual ISOLUTE EPH column uses a similar fractionation column sorbent mass to these published methods whereas the automated ISOLUTE EPH product and associated methodology provides reliable high throughput fractionation with substantial reductions in solvent consumption and costs, in some cases eliminating the need for evaporation of aliphatic and aromatic fractions prior to analysis.



Halvorson et al.

Evaluation of Several Columns and Solvents for Post-Extraction Chromatography (GPC) Clean-up of Fish Tissue Prior to PCB Analysis 

Michael Halvorson, Sr. Product Specialist, Gilson, Inc., 3000 Parmenter St., Middleton, Wisconsin, 53562

Thomas Gibson, Chemist, Wisconsin State Lab of Hygiene, 2601 Agricultural Dr., Madison, Wisconsin 53707

Curtis Hedman, Chemist, Wisconsin State Lab of Hygiene, 2601 Agricultural Dr., Madison, Wisconsin 53707

ABSTRACT

Gel Permeation Chromatography (GPC) is an effective and efficient post-extraction clean-up method for the removal of high molecular weight interferences such as lipids, proteins, pigments, natural resins and cellular components from sample extracts prior to analysis by GC, GC/MS, HPLC or LC/MS. GPC clean-up is often used for the clean-up of fish tissue extracts with high lipid content prior to analysis for halogenated compounds such as pesticides and PCBs. Traditionally, post-extraction GPC clean-up of fish tissue extracts is accomplished using a low pressure glass column containing Envirobeads^® SX-3 resin and a mobile phase of either methylene chloride or 1:1 methylene chloride:cyclohexane. While this column is highly efficient in the removal of lipids it has the disadvantage of relatively slow throughput per sample extract. The purpose of this study was to evaluate alternative columns and solvents for the post-extraction clean-up of fish tissue extracts that have faster throughput compared to the traditional GPC clean-up column prior to analysis for PCBs. Comparison of GPC calibrant elution times, lipid loading capacity and PCB recoveries from fish tissue for each column and mobile phase were determined.

Forsberg et al.

Mercury Concentration in Fish Oil Supplements by Cold Vapor Atomic Fluorescence Spectroscopy (CVAFS)

Poster Presentation

Prepared by J. Forsberg, D. Clarke, J. McQuatters and Jennifer Barry

CETAC Technologies, 14306 Industrial Road, Omaha, NE, 68144

Contact Information: jforsberg@cetac.com; 402-738-5433

ABSTRACT

Fish oil has become an increasingly popular dietary supplement as a source of omega-3 fatty acids. Fish oil contains both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which have been found to lower blood pressure, decrease buildup of plaque as well reduce the risk of several heart related diseases. Bioaccumulation of mercury in fish tissue has lead to fish consumption advisories in a variety of areas throughout the world. Fish oil has been designated an herbal supplement and therefore is not regulated by the Food and Drug Administration. In this study, we selected eight fish oil supplements and quantified the amount of total mercury present in the fish oil tablets. Samples were weighed and digested using hydrochloric acid to predigest the fish oil capsule which assisted in a total dissolution of the fish oil capsule. This approach mimics the natural occurring Gastric acid produced by the human body. The samples were further digested by combining the sample with additional acids and heated in a digestion block.  Mercury analysis was carried out on a cold vapor atomic fluorescence automated mercury system. The results showed that concentration of mercury varied slightly between supplement brands, which may be owed to similar fish species being used for the fish oil supplements by different supplement manufacturing companies. Results showed that the majority of the fish oil tablets are safe to use in the general public due to the recommended weekly intake of methylmercury of 1.6 µg per kg body weight set by the World Health Organization in order to sufficiently protect a developing fetus.

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