For many, autumn brings fond and happy thoughts: the changing fall colors, the increasingly crisp weather, and the joyous return of Pumpkin Spice Lattes (or PSLs). As you take a moment to enjoy these fine things and unwind, do you ever look down at your empty cup and wonder what is inside this latte that makes it so magical?
When some people order a PSL they are probably looking for a moment of comfort combined in espresso, steamed milk, and spice. Personally, when I drink one, I wonder about the exciting analytical challenge of trying to separate a mix of fats, sugars, caffeine, and organic acids with liquid chromatography.
Just like any complex sample, the mixture of a PSL is quite diverse and it is likely that no single column chemistry could separate all of the compounds so it helps to have a wide variety of column chemistries for screening. Fortunately the Thermo Scientific™ Accucore™ column family offers the widest selection of chemistries on a superficially porous platform giving me the best shot at separating the mixture fats, sugars and organic acids I anticipate are in the PSL. Using a core-shell particle column provides benefits in the analysis since these particles generally result in sharper peaks and faster chromatographic run times compared to a fully porous particle of a similar diameter, so I can sneak in a set of runs before heading home for the day.
To figure out exactly what is in that delicious PSL I ordered I knew that a C18 column could be the starting point for caffeine, but what other compounds would a C18 column be able to help me resolve? Would it separate lipids as well as the Accucore C30; could the spices resolve as well as they do on the Accucore Polar Premium? I was sure there would be some fat soluble vitamins in there, or at least I hoped there was as this way I could continue to tell myself that drinking the PSL was a “healthy way to start the day.”
Somehow I had some extra time in the lab and my fellow colleagues also had an interest in finding out exactly what was in the PSL I picked up on the way into work so we did a quick analysis for fun.
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We started by simply filtering our PSL sample through a Titan3 Nylon membrane filter and programmed a gradient of water and acetonitrile with 0.1% formic acid into our Thermo Scientific™ Vanquish™ Horizon UHPLC equipped with an Accucore C18 column. We installed a diode array detector in front of our Thermo Scientific™ QExactive™ Orbitrap mass spec to detect what was in our drink.
Within an hour we were on our way to finding caffeine, eugenol (found in clove oil and nutmeg extracts), 2-methyl butaldehyde (often used for chocolate or mocha coffee flavors), 2-methyltetrahydrofuran-3-one (coffee furanone; a volatile constituent of roasted coffee), cinnamaldehyde (gives cinnamon its flavor and odor) as well several other glycans, alcohols, diols and ketones by examining ESI positive and negative mode full scan data. And Jackpot! I found some fat soluble vitamins that have now reinforced my stance that PSL are “healthy.”
For me, this was a wonderful and fun afternoon spent around a cup of coffee – even if it was spent just a little bit differently than most PSL enthusiasts. In the process this latte brought me closer to my colleagues Kate, Craig, and Estee, and as we approach the end of the year, it is nice to reflect upon the happy moments and take a bit of a break from the day-to-day.
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To find out more about the data from these experiments, and how you can Discover More with Accucore, leave me a comment below!