Our lab is working on rapid, highly reproducible methods for the quantitation of APIs (Active Pharmaceutical Ingredient) in pharmaceutical preparations—i.e., the API is already in a tablet, together with a bunch of excipients, and we are developing analytical techniques to rapidly determine the precise amount of the API in a sample tablet. The lab already works on dispersive Raman techniques, but there are some pharmaceutical formulations of certain APIs for which Raman is poorly suited, due to fluorescence of excipients. We need to put such formulations into appropriate solutions to adequately remove those problematic excipients. Raman is fantastic for qualitative identification of the dissolved substances, but quantitation is still a challenge in many cases. We had initially been planning to apply LC/MS in most of these cases, but the liquid-chromatography adds an undesirable layer of complication. Since we are mostly interested in quantifying just the API, I wondered about the possibility of using the Raman ID data to select a small M/Z window, and then pass the solutions (or suitably diluted aliquots thereof), together with some appropriate internal reference standard, directly into a Mass Spec, and use the MS data for the quantitation. Since we'll be dealing with relatively clean solutions, it seems as though it might be possible to cut out the chromatographic separation step, which would save time, reduce noise associated additional sample-prep, and obviate the need for some solvents that we prefer to avoid.
I know that there are a variety of details that I've omitted (ionization...), but I wondered if anyone here knew of successful implementations of techniques along these lines. I have searched the literature as best I can, and I haven't found anything very helpful. I would be extremely grateful if someone could point me in the right direction of some relevant articles, or (fingers crossed) be able to lend any first-hand insights.
P.S. This is my first post. Apologies in advance for my English, and for any accidental breaches of forum decorum!