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Nail polish sample prep for GCMS and LCMS analysis
Hello,
I am an undergrad chemistry student and I am in a forensic chemistry class that is technically graduate level. I do not have much analytical experience, so I feel like I maybe bit off more than I can chew. I have a project for this class that involves analyzing nail polish via 3 instruments: DART MS, LCMS, and GCMS. I have a DART MS method planned out because it does not require sample prep. However, I am unsure of what to do with the nail polish to prep it for GC and LC analysis, so I am hoping to get ideas for the sample prep portion.
For GC: I am hoping to see if I can detect any toxic chemicals that may be present in the nail polish, specifically DBP, toluene, formaldehyde, and/or TPP. I have found a few research papers that mention using methanol as the solvent for the polish in GC. My concern is that I do not want to overload the column or clog it. How do I know if it will or not? How do I know it will be safe to put the nail polish in the GC with just mixing it in methanol?
For LC: I am hoping to see if I can get peak readings for the possible dyes or pigments in the nail polish. I have been unable to find any related research for this. I have some experience extracting dyes from nylon fibers via organic solvents and extracting by heating the mixture at 100 degrees C for an hour prior to putting the sample in LCMS. If I try the same with the polish, is it safe? Will the polish be too flammable (I think most are based in acetone or ethyl acetate but some of my samples I do not have the ingredient list).
I just don’t want to break anything or damage thousands of dollars of equipment and I do not have enough analytical knowledge to plan this myself. My professor is very hands-off and believes in trial and error, but I’m terrified.
Thanks in advance for any advice,
Crazy undergrad chem student who took a grad class too early
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6 Replies
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I don’t think methanol will act as a solvent for nail polish. Try it and see, but I doubt it very much.
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If you are to use HPLC, I would suggest normal phase instead of reverse phase chromatography. The best carrier solvent will be acetone (like the shop uses!) or toluene (never methanol in normal phase), though acetonitrile may be included in a programmed mobile phase addition if that is available, to vary the polarity and get better peak separation. GC will be much more forgiving, if flame ionization were the detector. With MS detection, I can’t say whether or not you will “gum up the works” inside that interferometer. Worst case, you have to take it apart and clean it out with polar solvent. In any event, good luck with your experiment and do share your results with us if successful.
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I am only familiar to GC-MS. What you can do if you have a complex matrix is to fractionate it (manually) using e.g. a silica column from non-polar to polar. After that you can choose the proper GC-coloumn for each fraction.
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personally, the first thing I’d do would be to run the sample through a centrifuge, in order to separate the suspended solids from the rest of the product, then run the chromatographic/MS tests on the supernatant fluid
all the dyes, resins and solvents will be in the supernatant fluid, and the pigments will be the solid matter at the bottom
also, for what it’s worth, it’s not possible to identify a substance unambiguously using only MS, but I’m sure you knew that already
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I am definitely going to take your advice about centrifuging first and seeing whats even there. Thanks for the advice
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To me, this seems a good way of ruining the sensitive (ergo expensive) parts of analytical equipment to provide information that nobody is interested in knowing.
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