Dilute & shoot ... yourself in the foot
October 21, 2020 at 8:30 AM / by Simonetta Tumbiolo posted in SLE Supported Liquid Extraction, Sample preparation, Method development, Clinical
Protein precipitation vs. traditional protein crash: what's best?
October 7, 2020 at 8:00 AM / by Stephanie J. Marin, Ph.D. posted in Sample preparation, Method development, Protein precipitation
Most clinical chemists have developed a blood, serum or plasma assay using a protein crash because it is inexpensive and generally removes proteins that interfere with detection or the analysis in some way. But is this always true?
Trying to develop a new method? How do I do a literature search?
September 4, 2020 at 8:34 AM / by Dan Menasco posted in Sample preparation, Method development
When trying to develop a new method for the detection of a drug panel, you need to refer to reliable sources to learn all you need to know regarding your analytes. For this post, we’ll go in detail through the search process with analytes like naloxone, buprenorphine, norfentanyl and methadone using urine as our matrix of focus.
Need good sources of reference for sample prep method development?
September 4, 2020 at 8:33 AM / by Dan Menasco posted in Sample preparation, Method development
The sole purpose for method development is to construct a robust and analytically sound method that will not just pass the barriers of validation, but provide physicians and patients with sound and reliable results. But where to start?
Why should I filter my samples instead of doing dilute-and-shoot?
August 26, 2020 at 8:00 AM / by Jillian Neifeld, MS posted in Extraction method optimization, Sample preparation, Method development
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.
Methods for a drug class or one large panel - what's the difference
August 23, 2020 at 8:00 AM / by Stephanie J. Marin, Ph.D. posted in LC-MS, GC-MS, Extraction method optimization, Sample preparation, Method development
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.
How to extract and analyze for ever-present contaminants of interest?
August 6, 2020 at 8:00 AM / by Jillian Neifeld, MS posted in SLE Supported Liquid Extraction, Sample preparation, Method development
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?
Techniques for disrupting protein binding in sample preparation
August 2, 2020 at 8:00 AM / by Bruce Kempf posted in SLE Supported Liquid Extraction, SPE solid phase extraction, Sample preparation, Solid-phase extraction, Method development
If you are frustrated with low recoveries caused by protein binding during Supported Liquid Extraction (SLE) and Solid Phase Extraction (SPE), this blog post will give you a few tips. Proper sample pre-treatment is the key to solving this issue.
Determining the Optimal Sample Size for your Sorbent Bed Mass
July 26, 2020 at 8:00 AM / by Jillian Neifeld, MS posted in Extraction method optimization, Sample preparation, Evolute Express CX, Sorbent, Method development