Re: how to detect hexane in skin product?

I cannot see a simple test for hexane. You will need a gas chromatograph or the like. I cannot imagine that small residual amounts of hexane have any neurotoxic effect. You really should look up the maximum concentrations permissible. The hexane will probably be used to extract the Shea Butter as it is a good solvent for lipids, and is then evaporated, as far as possible without damaging the end product. There is a simple principle in chemistry: you can find almost everything almost anywhere, if your methods are sensitive enough (think of nitrosamine in beer a couple of years ago). But it is the concentration that matters. Best regards - H.Oe.

Viator schrieb in im Newsbeitrag: snipped-for-privacy@g49g2000cwa.googlegroups.com...

Hi all, > > I recently purchased some raw Shea Butter, which is a > tree-derived butter that is supposed to be good > for the skin. However I want to test it, and subsequent > purchases of it, to make sure it is really, truly raw. > In the case of Shea Butter, it is typical that manufacturers > will treat it with hexane in order to (as far as I know) > whiten and deodorize it. Unfortunately the hexane > remains in the butter, and hexane is of course a neurotoxin. > > So I want to test it, and I could swear I've seen simple > disposable kits that people in labs use to detect > various chemicals, including hexane. > > Can anyone tell me where to get such testers? > > Thanks. >
Reply to
hoe
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Regards, Oliver

Reply to
Oliver 'Ojo' Bedford

Thanks Oliver.

I've discovered that not just Draeger but also Nextteq, MSA, and Sensidyne make gas detector tubes.

Prices: Sensidyne : US$50 per 10 tubes, plus $350 for the pump. Nextteq: $50 for 10 tubes and $450 for the pump. MSA: $230 for the pump but no hexane tube. Draeger: $460 for the pump, $70 for hexane tubes.

Draeger also makes a chip-based measurement device (!) for $3500.

And, 3M makes very cheap gas-detection badges, some of which are around $15.

Anyway I need to detect contamination in a solid, so I still don't have a solution :(

Reply to
Viator

With GC this is not really a problem. Headspace-GC measures the content of a substance in the gas phase above the matrix. You could do the same. Try heating the butter to the boiling point of hexane in a closed chamber and then measure the concentration of hexane in the "air". Of course, you would have to calibrate the method, e.g. by running trials with known amounts of hexane in your matrix.

Every analytical method has its problems regarding realiability, sensitivity, specifity etc. For that you should consult an expert. If you want quality management you certainly need a well worked-out standard operation procedure.

A single GC detection will come around $100. If you trust you supplier it could be best if you do one measurement at the start and afterwards only random sampling at longer intervalls.

Regards, Oliver

Reply to
Oliver 'Ojo' Bedford

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