Semi Automated Clean Up for Persistent Organic Pollutants Analysis in Environmental Samples - Complete Separation of PCDD/Fs and PCBs for Sample Extracts in Toluene

New Focus on Old Contaminants (e.g., lead, mercury, PCBs)
Oral Presentation

Prepared by

Contact Information: ruudaddink@toxicreports.com; 617-393-1713


ABSTRACT

Continued interest in Persistent Organic Pollutants (POPs), such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), and biphenyls (PCBs) has led to automation of both extraction and cleanup of complex sample matrices. This has resulted in development of fully automated sample cleanup instead of manual preparative open column chromatography.

In this contribution, we describe a semi-automated system which is cheap and effective for fast, reliable sample clean up, using a relatively simple approach. An important feature of this system is that the environmental samples can be in toluene (up to 10 mLs) and that all PCBs are collected in one fraction and all PCDD/Fs in another fraction.

The semi-automated system uses a rotary workstation with a vacuum pump to perform the entire sample cleanup in two stages with 2 simple steps. It uses four pre-packaged columns: high capacity acidic silica, neutral-base silica, alumina and carbon. In the first step, the carbon is left out, columns are conditioned (hexane), samples are loaded, and columns eluted with hexane, silica columns removed, and alumina eluted with 10% dichloromethane in hexane. This collects all PCBs in one fraction. Carbon and alumina are connected and columns are eluted with dichloromethane, alumina is removed and carbon is eluted with toluene. This collects all PCDD/Fs. Total processing time for 6 samples run in parallel is 45 min.

13C labeled recoveries for 10g soil extract were 70-110% for PCBs and 70-115% for PCDD/Fs. Because the system is mostly composed of disposable parts, risk of cross-contamination is very low. Note that a complete separation of PCBs and PCDD/Fs is achieved and that environmental samples in 2-10 mL toluene can be processed by loading directly. The system can be set up at low cost. Certified columns and the simple semi-automated system guarantee same day POPs analysis.