QuEChERS Extraction of Seafood -- 10 ng/g PAHs in Scallops, Shrimp, and Oysters

Continuing with the previous blog where I QuEChERS extracted 100ng/g PAH spikes of scallops, shrimp, and oysters, and achieved good results, I followed up with 10ng/g spikes under the same method conditions as used before (see June 28 entry). The recoveries for the 10ng/g spike are reported in the table.

In general, the results are good, but it’s obvious now for the cursory cleanup with dispersive SPE (PSA and C18) and the fast GC-TOFMS run on these moderately complex samples that I have some biasing interferences on indeno(123cd)pyrene and benzo(ghi)perylene (see table and chromatogram). Likely these can be sorted out with a more efficient cleanup or a longer, more efficient GC column, both at the expense of time. A better approach may be to keep the speed and focus on select European Food Safety Authority PAHs (highlighted in blue in the table).

Although these preliminary results (and the previously published peer-reviewed journal article from scientists in Portugal) suggest that QuEChERS is a viable approach to analysis of PAHs in seafood, justified skepticism on QuEChERS for these types of samples still exists in the community, so I’ll be doing incurred residues next. Stay tuned.