Previously, I spoke about how to focus our mass spectrometer’s source to maximize our analytes signal. We were interested in the detection of naloxone, buprenorphine, norfentanyl, and methadone in urine and determining their source parameters, but for this post, we’ll discuss the process behind tuning our analytes to the mass spectrometer’s optics.
Last time, I discussed how to gather information from the literature that would best suit our application for the detection of naloxone, buprenorphine, norfentanyl, and methadone in urine. Let’s quickly recap: we have our matrix and our analytes and a Shimadzu NexeraX2 LC with a 5500 Sciex MS. We did some searching and eventually settled on a poster we found on the Biotage website titled “Sample Preparation Strategies for Urine Panels with 50 or More Drugs and Metabolites Analyzed by LC-MS/MS.” Now what?
Previously, I spoke about the sources of information available for method development. We discussed some of the resources we could use to figure out how to build a method for the detection of naloxone, buprenorphine, norfentanyl, and methadone in urine. For this post, we’ll go through the search process with these analytes using urine as our matrix of focus. For this assay we’re running a Sciex 5500 triple quadrupole mass spectrometer with a Shimadzu NexeraX2 UHPLC. Since we’re not out to reinvent the wheel here, let’s assume this assay, in some form, has already been done. It’s likely Sciex has an application note with these analytes detected in urine. Perhaps all of them in are in a large, complex urine panel or they’re located in various other app notes with other vendors? Either way, the easiest approach is the simplest: first look for an application note from Sciex or other vendors that have as much similarity to our assay as possible. Continue reading When trying to develop a new method, how do I do a literature search?
In my previous post, I briefly mentioned the process of method development. Today, I’ll go into a bit more detail and will explain how to start the process so we can get a global view of what we’re doing, and more importantly, why we do it. The why: 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. Continue reading What are some good sources of reference for sample prep method development?
When running through the exhaustive process of method development, most of us put the majority of our focus on validation and how to complete our crazy validation checklists. Throughout this process, the last thing we want to see is some random hiccup in our workflow. But a whole validation without a hiccup is just wishful thinking, right? Whether your analytes are on back order or you have the misfortune of catastrophic instrument failure, we all experience some type of complication or mishap. One in particular, sample carryover, seems rather innocuous, but without some type of preventive action, it can really ruin a good method. Nonetheless, if you have preventative measures in place, this can be easily preventable.