Advances in Use of Multi Cartridge Solid Phase Extraction of Drinking Water and Waste Water Samples to Hyphenate Extraction, Drying and Cleanup

Poster-Vendor
Poster Presentation

Prepared by , M. Falkenstein

Contact Information: [email protected]; 617-393-2396


ABSTRACT

Use of multi cartridge (C18, florisil, sodium sulfate) Solid Phase Extraction (SPE) has led to significant advances in the possibilities to fully automate sample analysis for EPA methods 508, 525, 608, 625, 8081, 8082 and many others. Extraction, drying and cleanup can now be done as a true single step (hyphenated) process.

Method 525.3 outlines the procedure for the extraction and analysis of a wide range of organic compounds in water. This includes the use of SPE for water matrix samples employing cartridges. Consistent with other EPA 500 series methods, EPA 525.3 incorporates a rigid set of QC and acceptance criteria requiring precise and reproducible analytical practices. The potential for error and the variability associated with manual extractions makes the benefits of automating these processes apparent.

Reviewing 525.2 automated SPE data shows high recoveries for over 100 spiked analytes, demonstrating excellent efficiency for all classes of compounds. Low deviations between runs shows good run-to-run reproducibility.

The EPA 600 series methods focus on waste water samples that can prove a greater analytical challenge than finished drinking water. The presence of organic materials, surfactants, and other matrix interferences can pose extraction issues for both SPE and traditional LLE (Liquid-Liquid Extraction) techniques. Extract purification is also necessary in most samples, usually involving a Florisil clean-up step.

By using fully automated Solid Phase Extraction concentration and chemistries, it is possible to automate the extraction, extract purification and concentration steps of EPA 608. Analysis of the extracts yielded recoveries for all analytes tested well within EPA 608 acceptance criteria. Using C18 cartridges and inline sodium sulfate/florisil cartridges. 

In August of 2017 the EPA approved the use of fully automated SPE methods for 625.1. Using an automated SPE system (2 cartridges), a complete data validation protocol has been developed for EPA 625.1 that can be referenced and easily incorporated by testing labs wishing to make the transition from LLE to SPE. The validation protocol comprises the initial start up of IDC and MDL runs, various real world and synthetic matrix verifications, PT data for all required analytes, and a complete reference SOP.