Let's face it, the whole solid phase extraction method development process can be time consuming and expensive. So Dilute-and-Shoot methods end up being the choice in some laboratories. The problem is that these methods are dirty and lead to a lot of other issues. In this blog post, I'll be discussing filtration methods and how those are a superior option to Dilute-and-Shoot.
Most clinical and forensic labs have a used a traditional approach for drug testing called screen with reflex to confirmation. This involves analyzing samples using an immunoassay technique that identifies a drug class. Positive immunoassay results are then analyzed by a second more specific method, like GC-MS or LC-MS/MS, to identify and quantitate specific drug analytes.
Have you ever encountered problems loading your samples onto an SPE or SLE plate? Aside from sample viscosity or cartridge blockages, a good troubleshooting step to start with is ensuring that you are achieving complete frit coverage on the load.
Often the question arises asking how can I extract both acids and bases with the same Supported Liquid Extraction (SLE) procedure. Is this possible? And how?
It happens to all of us. We're getting a new method developed and validated and then it comes time to run our negative urines. And everything comes up as positive! There are peaks for our analytes of interest in every urine that we run! How is that possible?