Harnessing the Power of Mass Spectrometry and Automation to Reduce Sample Size, Sample Preparation Time and Increase Laboratory EfficiencyPer- and Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation
Prepared by K. Organtini1, O. Burt2, I. Wan3, K. Rosnack1
1 - Waters Corporation, 34 Maple St, Milford, MA, 01757, United States
2 - Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow, Cheshire, SK9 4AX, United Kingdom
3 - PromoChrom Technologies, 13351 Commerce Parkway, Unit 1103, Richmond, BC, V6V 2X7, Canada
Contact Information: [email protected]; 508-482-3242
ABSTRACT
US EPA Method 1633 has become the foundational method for analysis of PFAS in non-potable water matrices, soils, biosolids and tissues in the United States. The method consists of sample preparation using weak anion exchange (WAX) solid phase extraction (SPE) with graphitized carbon black (GCB) clean up. This EPA method is a performance based method allowing for changes to be made as long as data quality equivalency is demonstrated. With this method becoming very much in demand, laboratory throughput and efficiency must be considered for maximum laboratory success. Automation and instrument sensitivity are investigated as avenues to decreasing required sample size and therefore increasing laboratory efficiency.
A highly sensitive LC-MS/MS system was utilized for this analysis, allowing for reduction in sample volume size while still achieving equivalent results and method detection limits to the method. Sample volumes tested ranged from 500 mL (the recommended volume in EPA 1633) down to 50 mL using an automated solid phase extraction (SPE) system for sample preparation of water samples to eliminate the need for human interaction during the sample preparation process. To make the sample preparation process fully automated, a stacked dual layer cartridge containing both WAX and GCB chemistries was utilized instead of having to perform the GCB step manually.
Equivalency was established by demonstrating that all quality control guidelines were achieved including retention time stability, ion ratio stability, ongoing calibration verification, and recovery. Equivalency of the automated SPE system and stacked dual layer cartridge is also demonstrated as a complete workflow.
A method detection limit study will demonstrate equal or lower MDLs using the automated, reduced sample volume approach. Additionally, a wastewater certified reference material was processed in an equivalent reduced sample volume and was within all certified levels for the 40 PFAS covered by EPA 1633.
