question about mass spectrometry

[(zonk)]

I was looking to invest in good portable mass spectrometer but I'm not sure what the difference between units are. They range from like $40 to $10,000. I was reading about new lazer spectrometer by biozoom that's intended for measuring compounds in the blood by pointing the light at your arm!(not sure how legit it really is though). There's cheap portable gc/ms from inficon hapsite. Any tips or recomendations so i'm not getting in over my head/wasting money..?

 

[sekio]

There's no such thing as a "cheap, portable GC/MS".

Entry level units start at about $4,000 and up for used units. Plus lab space, plus helium/hydrogen, plus reagents, plus setup, plus $1000 for a GC column. A new unit is probably closer to $100,000.

I can assure you you won't find a mass spectrometer for $40. The Infinicon-Hapsite ones are designed for analysisng light volatile organics, (i.e. solvent reasidue) not doing pharmaceutical analysis...

Also, optical/laser spectrometry isn't what you want.

 

[(zonk)]

Yeah that $40 was something else, i've seen laptops with a wand attached to the USB to test for compounds/purities. What is this? Thanks for the info

 

[Hammilton]

Checking for solvent residue might be of value for those doing extractions on herbal compounds.

At home TLC would be particularly useful but I don't expect to see that one too soon

 

[sekio]

Home TLC is much more achievable. You can do a quick seperation with naptha/alcohol/acetone, and stain plates with e.g. acid and vanillin. Or iodine.

i've seen laptops with a wand attached to the USB to test for compounds/purities. What is this?

Not a GC/MS, that's for sure. Maybe Raman-IR spectroscopy.

 

[nuke]

Sometimes you can learn more much more quickly with straight up TLC and a shortwave/longwave UV wand or some stains to check for bands. This is especially the case when you're purchasing stuff like pure compounds and are looking for relative migrations or minor impurities.

More info here:
http://www.chemguide.co.uk/analysis/chromatography/thinlayer.html
http://www.watrex.cz/watrex/cz/dwn_ds.php?id=MACHEREY_NAGEL_TLC.pdf

I mostly run glass backed silica gel 60 TLCs, at this point in my career I've probably run hundreds. I always run them prior to GC/MS or LC/MS for organic synthesis or enzymatic products.

 

[electrodevo]

Melting point (if one is known for the compound) is also feasible at home and also can be a purity check. Same with freezing point depression, which can give you a molar mass figure if you know your compound is pure.

GC/MS and above are, in all practically, out of the range of anything at home. I've seen a few threads here and there on homebrewing a low resolution Raman spectrometer but I have no idea if that's useful for what you want to do.