Streamlined combustion gas measurements for improved national dioxin inventories

The analysis of PCDD/Fs requires advanced analytical instruments and is a complex, labor intensive process that consumes large quantities of high-purity solvents. It is therefore very expensive and thus problematic--or even impossible--for developing countries to afford to establish reliable PCDD/F source inventories in support of global and national emission reduction strategies. Low-cost reliable alternatives are needed to improve this situation. Therefore, a streamlined procedure for flue gas sampling and analysis has been developed and evaluated that utilizes a user-friendly polyurethane foam plug (PUFP) sampling technique. The collected samples are then shipped to a central laboratory for analysis where they are processed using a cost-efficient pressurized liquid extraction procedure with in-cell carbon cleanup (PLE-C) prior to analysis by gas chromatography--high-resolution mass spectrometry (GC-HRMS). The PLE-C technique has previously been validated for a range of matrices, and, in the present study, has been further improved by introducing an extraction cell coupling cartridge. The entire procedure was evaluated using three sets of samples: two from a laboratory-scale incinerator and one from a full-scale incinerator. The samples were expected to differ in PCDD/F levels and homologue patterns. Each sample was split and analyzed in parallel by both PLE-C and a reference procedure (Soxhlet extraction followed by a traditional multistep cleanup procedure, Sox-T). The results of analysis by PLE-C compared well with those from analysis by Sox-T. The difference between toxic equivalent (TEQ) values obtained using the PLE-C and reference technique for 11 PUFP samples ranged from -10% to +44% and the two techniques also yielded very similar PCDD/F homologue profiles. A principal component analysis (PCA) of the data showed that both methods were able to discriminate among the three sets of samples, thereby demonstrating that the between method variability was less than the between-sample variability. In summary, the results indicate that PUFP sampling followed by PLE-C extraction and cleanup provides a fast, relatively cheap, and reliable method for analysis of PCDD/Fs in flue gas.