Chlorinated Dioxins, Furans and Biphenyls Analysis in Complex Matrices Using Automated Extraction and Reduced Solvent Volume Column Chromatography

Oral Presentation

Prepared by P. Bassignani
Fluid Management Systems, 580 Pleasant Street, Watertown, MA, 02472, United States

Contact Information:; 617-393-2396


Analysis of various matrices for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and biphenyls (PCBs) has traditionally involved Soxhlet extraction (typically up to 24-36 h), followed by preparative multi-column chromatography steps. This process can include acid-base-neutral silica, acidified silica, alumina, and carbon columns. For the acid-base combination mixtures have typically contained 22%/44% sulfuric acid mixed with silica and 33% sodium hydroxide mixed with silica.

Automating sample extraction and clean-up have been implemented resulting in development of short time-frame Pressurized Liquid Extraction (PLE) – taking a total processing time of ~ 1 h as opposed to Soxhlet extraction – and the advancement of automated chromatography column sample clean up. Because of rising solvent costs in recent years, reduced volume programs for automated chromatography clean-up have been developed. Results are presented here.

1-5g sample was mixed with Hydromatrix™. Samples were put in extraction cells. Pressurized Liquid Extraction with 50%/50% v/v dichloromethane/hexane (120oC, 1500psi, 20min) was carried out. Cleanup was done with automated column chromatography, using high capacity acid-base-neutral silica, alumina and carbon/celite columns. Solvents used were: hexane, 10%/90% dichloromethane/hexane, dichloromethane and toluene. This results in complete separation of PCBs and PCDD/Fs in two fractions. Samples were analyzed with high-resolution GC/MS.

As an example, top soil gave very good recoveries of 60-100% for 13C labeled PCDD/Fs and 60-75% for 13C PCBs.

Automated extraction and clean-up of complex matrices followed by same day POPs analysis is now possible. Our new reduced volume column chromatography program uses less than of 350 mLs of solvents with a maximum processing time of 40 mins.