Introduction
Polybrominated Diphenyl Ethers (PBDEs) are aromatic, non-polar compounds formerly used as flame retardants. These compounds were determined to be toxic and are now included on the Stockholm Convention’s list of persistent organic pollutants (POPs). Though their use has been restricted or banned in many areas, low levels of remaining PBDEs in biological, environmental, or food sources are subject to bioaccumulation and can still result in detrimental reproductive and other health effects.
This work utilizes a new method and technology that provides fast quantitation of toxic PBDE congeners with short run times and includes the quantitation of BDE-209 in a single analytical run. This improved procedure allows significant time and cost savings by eliminating the need for additional columns and instrumentation traditionally required to achieve sufficient separation of all PBDE congeners. Comparison of existing methods and the single-test method are included, highlighting improved sensitivity and shortened run times.PBDEs consist of 209 individual conformations called congeners, which vary in toxicity. Analytical testing of these congeners is performed by high resolution gas chromatography with high resolution mass spectrometry (HRGC/HRMS) to achieve the lowest levels of detection and highest degrees of confidence possible. Even using this advanced instrumentation, achieving accurate, well-resolved separation of all congeners proves difficult. PBDE analysis is historically problematic for two main reasons: the sheer number of compounds and analyte stability. In addition, some congeners are thermally labile, sensitive to column activity, or both. The most notorious of these reactive congeners is BDE-209, decabromodiphenyl ether. Complete testing of BDE-209 is especially important because it can break down in the body or environment to even more toxic congeners. To obtain resolution of the all 209 congeners, many labs analyze a single list of PBDEs by two separate tests. The first uses a detailed method that resolves most congeners and traditionally employs a low polarity column of 60 m x 0.25 mm ID dimensions. However, this configuration results in nearly hour-long run times. As a result, the latest eluting congener BDE-209 frequently displays dramatically reduced peak response due to extended exposure to thermal degradation and column activity.Labs are, therefore, often forced to analyze this compound with a second method, typically using a separate instrument and a much shorter, thinner phase column that will provide less retention. This allows a lower elution temperature and helps address thermal stability issues for BDE-209. However, thinner phase columns are more susceptible to activity, leading to peak tailing and more difficult quantitation. This work addresses the contribution of thermal stability and column activity to BDE-209 breakdown and also provides an optimized method that resolves important congeners as well as BDE-209 in one short run.
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