Relax – Here’s an LC-MS Analysis for Bath Salts!

Jack posted a blog on June 16th that mentions a Pennsylvania ban on both ‘bath salts’ and ‘spice’. Since I already have a couple of blogs on spice, I figured this time I’d blog a little bit about the work we’ve been doing on bath salts here in the Innovations Lab. The work is still in progress, but so far we’ve developed both a GC-MS and an LC-MS method for a few of the most common bath salt compounds. I’ll talk about the LC method in this post and the GC method in a future post. When we developed our method, for the bath salts, we thought it would be useful to be able to screen for the bath salt compounds (a.k.a. cathinones) at the same time as amphetamines, since structurally the two compound classes are so similar.

With our analysis well in-hand, we paid a visit to our local headshop and picked up a few bath salt products to try with our new method. We only bought three samples to begin with, but we found that two out of the three samples contained methylenedioxypyrovalerone (MDPV), while the third sample contained mephedrone. We also did a quick one-point quantitation on the samples to determine a ballpark purity, and based on the results we got, the purity for these products can vary greatly.

Based on news reports from the states banning bath salts, it looks like MDPV is under the largest amount of scrutiny from lawmakers, and based on the small set of results we got here in our lab, as well as some word-of-mouth from customers, it seems like MDPV is currently the additive of choice for bath salts.

As always, I’d love to hear from readers who have any questions or comments on this or any other post, but this time I have a question for my readers: What components are added as cutting agents for the bath salts? When we were preparing the salts for analysis, we observed that the sample would not completely dissolve in a 60:40 MeOH:H2O solution. We ended up dissolving the samples in pure water instead.

3 Responses to “Relax – Here’s an LC-MS Analysis for Bath Salts!”

  1. Dr. Uboh, Cornelius says:

    Dear Amanda Rigdon,
    Great info.
    Have you been able to recover these reference standards from plasma and urine after they had been spiked in the matrces? If so what method of extraction did you use and what was the percent recovey?
    Dr. Uboh

  2. Thank you for your comment, Dr. Uboh!

    I tried a few different ways to extract these compounds from urine. First, I attempted a basic (pH ~ 12) liquid/liquid extraction with butyl chloride. This method worked for all of the compounds, with the exception of MDPV, which did not extract well, making this LLE method unsuitable.

    In collaboration with Mike Coyer from Northern Tier Research, we tried two different methods for extracting these compounds using SPE: traditional SPE tubes, and Xcel Tubes from UCT. We didn’t collect any validation data for this preliminary work, but based on the curve I analyzed (1ng/mL – 500ng/mL), both extraction methods worked well. The main difference between the two extraction methods was that the extraction using the Xcel column was much faster. For more details on extractions with Xcel columns I’d suggest that you take a look at UCT’s Xcel brochure.

    Although SPE cleanup is definitely an option for bath salts, it seems like the levels in urine are such that one can get by with a simple 20:1 dilution to cover a the clinically-significant range for these compounds, which I estimate would be between 50ng/mL and 5000ng/mL. In addition to the high levels present in urine, most of the bath salt compounds are excellent ionizers, which will help out on the sensitivity side as well.

  3. [...] My colleague, Amanda Rigdon, was out in front of this issue with her analytical work as reported in her blog, “Relax – Here’s an LC-MS Analysis for Bath Salts!“ [...]

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