Analysis of Dried Blood Spots for Polychlorinated Biphenyls and Organochlorine Pesticides by Gas Chromatography Coupled with Tandem Mass Spectrometry

Abstract

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) are anthropogenic pollutants highly resistant to chemical degradation and readily absorbed by organic tissue. Their persistence in the environment and toxicological threat to mammals prompts swift, reliable methods of analysis. This study outlines a rapid, efficient and sensitive, validated methodology utilizing a simple liquid extraction technique, and subsequent analysis by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) for the determination of PCBs and OCs from dried blood spots. The PCBs and OCs were quantified in whole marine mammal blood spotted on Whatman Protein Saver cards (PSCs) by extracting the analytes into acetonitrile acidified with formic acid, followed by GC-MS/MS analysis. The samples were analyzed in positive electron impact (EI+) ionization mode with the electron energy set to 40 eV to preserve analyte integrity. Fortified blood with the analytes of interest was used for method validation and subsequent sample screening. The recoveries of targeted analytes ranged from 62.5% to 107.8%, with relative standard deviations ranging from 0.09% to 4.6% at a 100 ng·mL⁻¹ concentration level. The method detection limits were from 40.4 ng·g⁻¹ to 179.2 ng·g⁻¹ for the PCBs and 37.6 ng·g⁻¹ to 145.1 ng·g⁻¹ for the OCs. The use of dried blood spots provided for numerous advantages compared to whole blood samples while demonstrating reduced matrix effects and enhanced sample lifespan while retaining analyte sensitivity.

Keywords:

• Dried blood spots
• gas chromatography/tandem mass spectrometry
• organochlorine pesticides
• polychlorinated biphenyls

Acknowledgments

We acknowledge valuable guidance provided from Kim Lilley, Jing Zhang, and Stephen Harrington of Waters Corporation (Milford, MA, USA) on the sample preparation and the analysis. Special thanks to Aliaksander Yeudakimau and Gary Ulatowski who were involved in the early stages of method development and sample preparation of this study.

Conflict of interest

The authors confirm that this article content has no conflicts of interest.