针对用于萃取后凝胶色谱法分析Fish Tissue Prior to PCB的色谱柱与溶剂的评估

The determination of PCBs, as well as other environmental contaminants, in fish tissue
requires extensive sample cleanup prior to analysis by gas chromatography with an
electron capture detector (GC-ECD). The high fat content of fish tissue can cause
buildup of nonvolatile materials on the GC injection port and the analytical column
resulting in poor analytical results and high instrument maintenance costs.

Gel Permeation Chromatography (GPC) is a size-exclusion clean-up procedure that
uses organic solvents and a hydrophobic gel (primarily a cross-linked divinylbenzenestyrene
copolymer) to separate macromolecules. It is a highly effective method for the
removal of high molecular interferences such as lipids, proteins, pigments and cellular
components from animal tissue.

GPC clean-up is often used for the clean-up of fish tissue extracts prior to analysis for
halogenated compounds such as PCBs and chlorinated pesticides. The most common
GPC clean-up procedures for fish extract cleanup utilize a 700 mm x 25 mm glass
column containing 70 g of Bio-Rad Envirobeads® SX-3 resin with a mobile phase of
100% dichloromethane or 60 g of Envirobeads SX-3 resin with a mobile phase of
1:1 dichloromethane/cyclohexane at a flow rate of 5 mL/min. Although both columns
are highly efficient in removing lipids from fish extracts, sample throughput is limited
to approximately one hour per sample extract and both clean-up procedures utilize
large amounts of solvent per sample.

The purpose of this study was to use a Gilson GX-271 Automated GPC Clean-up
System (Figure 1) to evaluate several GPC clean-up columns and mobile phases that
would give faster throughput and use less solvent for the post-extraction clean-up of
fish tissue prior to PCB analysis via GC-ECD.