fish, PAH, food testing, GC-MS/MS, Thermo Scientific

There continue to be oil and other fuel spills and contamination everywhere. It’s not that we do not want the oil, we need the energy for our economy. Care must be taken so that we minimize our impact. This care also takes the form of care for ourselves. The seafood and specifically the fish that we eat can get contaminated. Oil and other fuels contamination can come even when and where you least expect it. Who would have ever guest that a cruse ship would have run aground just off a small island in the Mediterranean close to Italy. Fish are generally mobile; sometimes they can avoid the contamination. When the fish is really contaminated it’s easy to see, they are coated in the oil and probably swim funny. When there just enough oil to get into the body you will not know it’s there without testing. PAHs do get metabolized in the meat but the speed of that depends on the species and there will be parts that the toxins will not be removed. Ensuring that oysters and now fish are free of this type of contamination prior to human consumption minimizes our exposure to these toxins through ingestion.

This method can be applied to fish to detect the presence of aliphatic hydrocarbons and PAH contamination from crude oil. From the profile using GC-MS/MS, the method can be used to characterize the source of contamination. The method can give a semi-quantitative indication of whether levels of PAHs exceed safety limits for human consumption of oysters. A liquid extraction of fish with hexane, followed by a clean-up on a silica-SPE-cartridge is used. The sample is fortified with appropriate labeled internal standards and analyzed by simultaneous GC-MS/MS using a TSQ Quantum XLS. Aliphatic hydrocarbons and PAHs of food safety significance are measured and compared with the profile from crude oil collected from the Gulf of Mexico in late May 2010.

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Accuracy was demonstrated by analysis of a smoked fish proficiency test material (FAPAS T0642) which had assigned values for the significant PAHs. After following the full extraction and cleanup procedure, the FAPAS sample was analyzed by GC-MS/MS and the results are given in the application note. Average recoveries of B(a)A, B(a)F, B(a)P, I(1,2,3-c,d)P and B(g,h,i)P were 101, 96, 97, 116, and 94% respectively. The accuracy of the method for the critical PAHs in fish was demonstrated. Accuracy was also demonstrated by analysis of a blank fish spiked with a solution of NIST crude oil containing certified levels of PAHs. Following the full extraction and cleanup procedure, samples were analyzed by GC-MS/MS and the results are provided in the application note. Average recoveries of B(a)A, B(a)P, I(1,2,3-c,d)P and B(g,h,i)P were 1.7, 112, 82, and 112% respectively.

Download the application note here; PAH in Fish