Automated Clean up Method for the determination of PCDD/Fs in Long Term MSWI emissions Andrea Colombo1, Marco Lodi1, Simone Caimmi2, Gianluca Rossetti3, Andrea Manni3* 1Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Department of Environmental Health Science, Via La Masa 19, 20156 Milan, Italy andrea.colombo@marionegri.it 2Environ-Lab, via don Bosco 3, Genzone (PV), Italy simonecaimmi@envirolabsrl.it 3*Chemical Research 2000 Srl, Via Santa Margherita di Belice 16, Rome, Italy info@cr2000.it Introduction The officially Reference European Standard method with respect to the determination and verification of compliance with the legal limits of PCDD/Fs in industrial atmospheric emissions is UNI EN 1948 entitled: Emissions from a fixed source - Determination of the mass concentration of PCDD / PCDF and dioxin PCBs similar - Parts 1 - 2 and 3 respectively related to sampling, extraction and purification and finally the identification and quantification of PCDD / PCDF. The recent introduction of EN 1948-5 addressed the principles and minimum requirements for long-term sampling of PCDD/Fs. It offers the advantage to cover all operation periods of the investigated plant, such as start-up and shot-down when levels of PCDD/Fs might be considerably higher. Long Term sampling involves larger volumes increasing the difficulty in removal of many potentially interfering chemicals. Reference methods for the quantitative analysis of PCDD/Fs involve successive clean-up steps on various chromatographic adsorbents (multi-layer silica, Florisil, alumina, activated carbon) which considerably increases the time needed for analysis. The objectives of this study were to provide a simplified clean-up procedure, capable of working on the long-term sample extract, through the assessment of an automated clean-up system based on gel permeation chromatography combined with an in-line concentration system and solid phase modules able to manage the acid silica/neutral silica and basic alumina purification. The system processes the samples in series. A further purpose with the introduction of an automated clean-up system is to reduce the gap between short–term sampling and on line monitoring, actually not available for the determination of PCDD/Fs in stack emissions. Experimental details Extraction 28 samples which were spiked with a mixture of 13C-labelled PCDD/Fs standards (Wellington Laboratories, Canada) and extracted by an ASE 300 (Dionex Inc. Sunnyvale, CA, USA) using the following instrumental parameters: System Pressure: 1500 psi Oven Temperature: 80 °C Oven Heatup Time: 5 min Static Time: 15 min Solvent: Dichloromethane Flush Volume: 60% of extraction cell volume Nitrogen Purge: 1 MPa (150 psi) for 60 s Clean up Clean up was performed by the means of an automated system composed by three modules shown in figure 1: GPC, SPE and evaporation (J2 Scientific, MI, USA). The used procedure is reported in the flowsheet below (fig.2): Instrumental Analysis The pollutants were detected by a GC coupled with a high-resolution mass spectrometer, operating in the electron impact ionization (EI+) mode, at 10,000 resolution power. A capillary column (60 m x 0.20 mm x 0.25m) with splitless injection was used. The PCDD/F temperature program for analysis was 160°C for 1 min, 2.5°C/min increase until 300°C, 300°C maintained for 6 minutes. The ions were scanned in the selected ion-monitoring (SIM) mode. The ions monitored were tetra- chlorinated congeners and M+2 and M+4 for penta-, hexa-, hepta- and octa- chlorinated congeners. Peaks were accepted if the isotopic ratio was within 15% of the corresponding ratio in the internal standard (IS). Limits of detection (LOD) were calculated individually for each sample on the basis of a signal-to-noise ratio of 3:1. Field and analytical blanks were run covering the whole sampling and analytical procedure. Blank PCDD/F samples showed no peak. Results and Discussion PCDD/F concentrations at the MSWI chimney ranged from 0.00