Evaluation of High Throughput, No Methylene Chloride, Low Cost Sample Clean Up for POPs Analysis

New Environmental Monitoring Techniques for Organics
Oral Presentation

Prepared by , T. Hall

Contact Information: ruudaddink@toxicreports.com; 617-393-2396


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 a minimum amount of solvent is used, and no dichloromethane is used at all. This is important since many laboratories around the world are phasing out this solvent.

The semi-automated system uses a rotary workstation with a vacuum pump to perform the entire sample cleanup in two stages with 3 simple steps. It uses three pre-packaged columns: mini silica (removes 200 mg lipid) or high capacity silica (3 g lipid removal), carbon and alumina. In the first step the sample is loaded onto the silica column manually (1-5 min). In the second step the three connected columns are eluted with hexane transferring dioxins, furans and co-planary PCBs onto the carbon column and mono- and di-ortho PCBs onto the alumina column. In the third step (second stage) both carbon and alumina are eluted individually with toluene to collect the respective analytes. Total processing time for 6 samples run in parallel is 30 min. For the mini silica kit solvent use is as low as 90 mLs.

A variety of matrices - eggs, feed, oils, soils - showed very good recoveries (70%-110%) for both PCDD/Fs and PCBs. Because the system is mostly composed of disposable parts, risk of cross-contamination is very low. The system can be set up at low cost. Certified columns and the simple semi-automated system guarantee same day POPs analysis.