GEN-MKT-18-7897-A
Dec 14, 2021 | Blogs, Environmental / Industrial, Food and Beverage | 0 comments
US Environmental Protection Agency (EPA) and Department of Defense (DoD) methods for testing per- and polyfluoroalkyl substances (PFAS) in drinking water require using solid phase extraction (SPE). SPE has been used extensively in environmental contaminant analysis both for concentrating large sample volumes (improving method sensitivity) and removing matrix interferences (sample cleanup).
Although SPE is a highly selective method for sample cleanup, there are some instances where testing laboratories might prefer to use direct injection, also known as large volume injection. Direct injection can be a much quicker and simpler option for high-throughput applications such as testing drinking water. Direct injection methods benefit from minimal sample preparation and decreased risk of lab-based PFAS contamination.
Both sample preparation methods are useful as the need for rapid and robust PFAS testing increases. So which method is right for your application? Here, we look at the pros and cons of using SPE vs. using large volume injection.
Using SPE Using SPE for testing drinking water ensures that your methods meet EPA and DoD requirements. SPE is also required by some US states. This makes SPE a great option when testing for any governmental requirements. SPE is also a well-proven method that delivers robust results for large sample volumes, and SPE cartridges are widely available commercially.
There are some downsides to using SPE, however. SPE requires longer sample preparation times than direct injection, and it requires additional training for sample prep technicians to ensure that samples are not contaminated. SPE can also add some quantitative method variability. This can be largely mitigated by the use of internal standards, but LOQs for PFAS analysis are often limited not by the analytical LC-MS/MS method, but by the variability and background contamination introduced by performing SPE. This can limit the usefulness of SPE.
Using direct injection/large volume injection Direct injection is less time consuming than SPE and requires less sample preparation, which decreases the risk of lab-based contamination. Direct injection also requires no extraction. This method is suitable for cleaner samples, such as drinking water and some surface and ground waters, and it allows testing laboratories to provide more high-throughput offerings to clients and therefore more environmental testing options.
There are also some cons to using direct injection. It is not allowed in many regulated methods, which limits its application, and it has not been evaluated by the EPA. In addition, dirtier, more complex sample matrices can result in LC system and column clogging or high matrix effects.
When to use which The method best suited to your application will depend on your unique situation and the needs of your lab. Learn more from our experts about the benefits of using direct injection or SPE methods for PFAS testing to help you make the right choice.
The Echo® MS+ system is a novel platform for Acoustic Ejection Mass Spectrometry (AEMS) and combines the speed of acoustic sampling with the selectivity of mass spectrometry. This platform has been designed for high throughput analysis of small and large molecules. The technology combines Acoustic Droplet Ejection (ADE), an Open Port Interface (OPI) and could be coupled with the SCIEX Triple Quad 6500+ system or the ZenoTOF 7600 system.
The Echo® MS+ system comprises of an open-port interface (OPI) and acoustic droplet ejection (ADE) module which could be coupled with a mass spectrometer. The mass spectrometer could either be a SCIEX Triple Quad 6500+ system or the ZenoTOF 7600 system. This non-liquid chromatography based; high-throughput screening platform enables rapid analysis of compounds at speeds of up to 1 sample/second.
The ability to consistently achieve reproducible results on many complex samples across multiple days is critical to a routine clinical laboratory. Laboratories relying on analytical instrumentation require stability and robustness to perform a variety of screening and confirmatory assays with confidence. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become the preferred analytical method in the clinical laboratory to reliably perform clinical testing as it provides best-in-class performance and reliability for the most challenging assays. LC-MS/MS offers the required levels of sensitivity and specificity for the detection and quantitation of molecules from complex biological samples, helping laboratories deliver highly accurate data for a variety of clinically relevant analytes across a wide range of assays.
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