Since 2009, we have analyzed polychlorinated biphenyls (PCBs) in environmental samples from the Arctic (two snow and ice projects) and at U. S. industrialized sites (two tree bark projects) using high-resolution mass spectrometry (HRMS) with method EPA 1668A/C. These are contrasting environments where there are no likely PCB sources – in the Arctic - but significant sources at industrial sites. The benefits to using HRMS include analyte detection to 0.001 AMU and lower detection limits, resulting in smaller sample sizes and lower field work and shipping costs. A benefit specific to PCB analysis is reporting of all 209 congeners. While separation of compounds results from the column used in the gas chromatograph upstream from the HRMS, there have been individual benefits resulting from identification of PCB congeners in unlikely quantities in comparison to PCBs that were widely used showing that PCB congener make-up of samples appears to be changing over time. Analysis of PCBs in the Arctic has shown comparatively high concentrations of PCB-5 and PCB-11, neither of which was produced in large amounts in any commercial PCB product, but likely both co-synthesis contaminants in pigment production. In tree bark and air samples from Native lands in North America where 1668A/C is used, we are seeing high concentrations of PCB-4 in in some samples. While PCB-4 was not widely used, it is known to be a dechlorination product in contaminated aqueous systems at industrial areas contaminated with PCBs. It is also known that PCB-4 is a significant human neurotoxin, so it is critical to follow its movement in aqueous systems and in the atmosphere. The disadvantages of HRMS method EPA 1668A/C for PCB analysis is cost of standards and very large data sets requiring more time to complete analysis, and more investigation of PCB congeners not usually found in PCB products.

Using high-resolution mass spectrometry for analysis of polychlorinated biphenyls in environmental samples: 12 years of observations

ACS Spring Meeting 2021

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