Due to the urgent need for rugged, reliable methods to determine polycyclic aromatic hydrocarbon (PAH) compounds in seafood from the Gulf, AOAC expedited a process that, ultimately, led to a candidate method ready for AOAC validation. AOAC facilitated a stakeholder panel and working group meetings; established a fitness-for-purpose statement; issued calls for methods and collaborators; evaluated available methodology purported to meet fitness for purpose; and selected the best candidate method for further evaluation and validation—all within 3 months. Further, AOAC has developed, and is currently finalizing, a validation study protocol, and the method is about to enter into collaborative study. AOAC validation of a method to detect PAHs in seafood is expected to take less than 6 months from start to finish.

In choosing a candidate method, AOAC reviewed approximately 30 methods for the detection of PAHs. Consequently, the PAH Working Group on Quantitative Methods, chaired by Gina Ylitalo, NOAA NWSFC, recommended a method by Lucie Drabova et al. at the Institute of Chemical Technology in Prague, Czech Republic as the most promising candidate method for further evaluation and, ultimately, validation as an AOAC-approved method.

In general, the method (Rapid Method for Simultaneous Determination of PAHs, Polychlorinated Biphenyls, and Polybrominated Diphenyl Ethers in Fish and Seafood Using GC-TOF/MS) is easy to perform, uses common laboratory equipment, and meets fitness-for-purpose and AOAC single-laboratory validation (SLV) requirements. The method uses a gas chromatography system coupled to a mass spectrometer detector that allows identification and quantification of all target PAHs.

Due to the urgent need for a reliable method, it was recommended that the project initially focus on three seafood matrixes (mussels, shrimp, and oysters). It was also agreed to expand the technique beyond time-of-flight (TOF)/MS to include any mass spectrometer in the collaborative study.

The study will evaluate the performance of the method when used to determine PAHs in shrimp, oysters, and mussels. Analytes for the collaborative study have been narrowed down to include only PAHs and some of the relevant PAH alkyl homologues. Benzo[a]pyrene (BaP) is the analyte of main interest and will be at a range of 2 to 50 µg/kg. The concentration range of the other contaminants will vary from 2 to 250 µg/kg. The target limit of quantification (LOQ) estimated as the lowest calibration level (LCL) is 0.5 µg/kg (fresh weight basis) for BaP.

Once the draft collaborative study protocol is finalized, it will be submitted for review to a method-centric committee. If approved, it is expected that laboratories can start the study by fall 2010, with data to be reviewed by a method-centric committee by the end of the year. As of October 6, 2010, AOAC has confirmed 15 laboratories to participate in the study.

For more information, contact Dawn Frazier, senior director, membership and education, at dfrazier@aoac.org or Krystyna McIver, senior director, stakeholder communications, at kmciver@aoac.org.

Full coverage is scheduled for the September/October issue of Inside Laboratory Management.

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