Nail Polish GCMS LCMS

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

8 posts Page 1 of 1
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 but some of my samples I do not have 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. :shock:

Thanks in advance for any advice,

Crazy undergrad chem student who took a grad class too early
Unless you have been assigned this project as you describe it your first move needs to be to pick one of the three, and forget about the other two.

Unless you are sourcing the nail polish from very dodgy suppliers the chances that you find anything toxic (by which I mean real toxins not those that internet whiners go on and on about) at anything above ultra-trace level are too low for them to be the basis of a class project.

I think that you will find that a lot of the colour in nail polish is pigment, not dye, so it will be difficult or impossible to analyse by chromatography.

I would have thought that any forensics to do with nail polish would involve dried polish - not straight form the bottle, so your concerns about flammability would fall away.

Forensic analysis is a lot more difficult than it looks on CSI, so do not be too ambitious.

Peter
Peter Apps
Way outside my field, so I'm pontificating here, but if you're interested in identifying nail varnishes would reflected spectroscopy make more sense? I don't know how small a sample it can use. Of course you'd be looking only at colour, but it'd be useful to be able to match samples. Though I'm sure it must have been done.
I'd worry about analysing scraped-off bits of nail-varnish found stuck on something because they're going to sample not only the nail-varnish, but also the personal hygiene and recent history of the person who wore it, and the cleanliness of the surface on which the nail-varnish was found.
I agree with Peter, but if you do end up doing any LC-MS (which is my area), there's not much you can do with the sample to kill an instrument. The essential is that the sample must be completely soluble and contain no solid bits. The worst-case scenarios are that you can inject something that binds permanently to the column (in which case your professor may have got himself a non-unbearable bill to replace it - more fool him; if you use a guard column, you can just change it), or you get your sample to dissolve, but because it doesn't ionise, you're tempted to inject more and more until you block some part of the MS (spray needle or ion transfer capillary (or whatever it's called on your instrument)). These can usually be cleaned, or in case of total disaster, replaced. If in doubt, start dilute.
"If in doubt, start dilute."

An excellent maxim - both when doing chromatography and when drinking !!

Peter
Peter Apps
Ok, thank you very much! I honestly only wanted to use DART MS and make a nail polish fingerprint sort of library, but my professor insisted on the LCMS and GCMS. I think I will try your advice about starting super dilute with maybe methanol as the solvent for both GCMS and LCMS. If it becomes too daunting for the timeframe I have to complete this or if it is largely inconclusive, I will just have to talk to my professor about feasibility.
For your original list, formaldehyde is nearly impossible by GCMS without derivitization since the molecular weight is the same as methanol and oxygen which will both be interferences. Formaldehyde is best done by derivatizing with Dinitrophenylhydrizine(DNPH). There are methods for this listed as EPA1667 and EPA8315. These are for solid and liquid samples but there are also NIOSH methods for analyzing for it in air, which could be a good project to see if you get any hits for it in the fumes as the sample dries.

Most of the GCMS analytes you listed are going to be volatile, so if you have access to either purge and trap or headspace sampling that would help with those. Also SPME would be a good technique to recover the analytes which offgas as the samples dry.
The past is there to guide us into the future, not to dwell in.
I may be able to finally repay some of my debt to this site. Prior to undertaking my PhD in entomology I was a forensic scientist and studied for my BSc and MSc in the subject.

If you are looking for contaminants within the nail polish, I would have thought headspace analysis using SPME-GC-MS or TD-GC-MS would be the most appropriate. Although, as Peter suggested, I doubt you would find many contaminants within your samples if acquired from respected outlets.

Perhaps you should consider a slightly different angle to the project. For example, lets say we are investigating a murder where an individual struggles with the victim and in the course the aggressor scrapes some nail polish from the victims nails using his own nails. If we take under nail scrapings from a suspect and found flecks of nail polish we would want to determine two things primarily:

1. Does the colour match that of the victim's nail polish?

2. Does the chemical make-up of the nail polish match that of the victim's nail polish?

The analysis of paint can take on three forms; mechanical, physical and chemical. The mechanical analysis will attempt to make matches between flakes of paint, similar to reassembling a jigsaw puzzle. The chemical analysis aims to establish the exact composition of a sample using various chromatography techniques. The physical analysis of paint relates to colour, texture, thickness, appearance, and the pattern of occurrence.

While there doesn't appear to be a lot of work on nail polish analysis, automotive paint is quite commonly analysed in cases so perhaps some of those techniques would be applicable to your work?

I assume you're only interested in the chemistry side of things as it's a chemistry class. So you would want to investigate the composition of the nail polish to determine whether there is a match between suspect and crime scene.

Although you could apply chemical methods to analyse the colour, e.g. FTIR spectroscopy or analyse the elemental components using energy dispersive spectroscop, I assume as you're on a chromatography forum you'd like to use chromatographic techniques. This relatively recent review uses GC-MS and LC-MS for paint analysis, so the techniques would be applicable for nail polish: https://www.esciencecentral.org/journals/recent-applications-of-mass-spectrometry-in-paint-analysis-2329-6798.1000109.pdf. These authors analysed the chemical components of face paints using LC-MS: http://onlinelibrary.wiley.com/doi/10.1111/ics.12181/abstract;jsessionid=8A22A543A057FBA484FFA39D2F3A0520.f02t04. Pyrolisis GC-MS seems to be a common method of pain analysis too: https://shop.perkinelmer.co.uk/Content/ApplicationNotes/FAR_GCMSAutomobilePaint.pdf

Not sure if that helps or confuses the situation. Happy to help further if needed.

Cheers,

Joe
Thanks Joe,

We just did a lab on ignitable liquids and used headspace analysis! If I shift my project focus to nail polish chip analysis via headspace, it would definitely be relevant and more forensics oriented (and virtually inexpensive aside from the activated charcoal strips, which I believe my lab has plenty). I will talk to my professor about it!
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