[rajan]

I'm looking for some tips on how to get my glassware cleaned. Specifically, can I clean my NMR tubes and a really nice quartz cuvette (for photoluminescence) with strong acid?

i know i'm not supposed to put the NMR tubes in base or an oven (although i have a hard time believing either of those will completely ruin it), but i want to know for sure if acid is ok.

the quartz cuvette is ok in the oven (i assume), but i think they don't like base baths, so acid is my clearest option.

[russellm72]

Have you looked at chromic acid for cleaning glassware?

I also find if you DONT leave your NMR tubes around for ages and clean them out quickly they should be Ok. If I had DMSO in there I'd use a NMR tube cleaner (Aldrich) rinse with MeOH then DCM before blowing dry in a stream of N2 not in the oven. Other less polar solvents just rinse with them then DCM as above. Don't leave in the tube for ages for things to go off or solvent to evaporate leaving a stubborn pellet in the bottom.

In saying that I use a new tube everytime because thats the law where I work. Damm disgrace but I'm not in charge so Hey

R.

[Arkcon]

Base attacks silica, at least a little bit, so extended soaking in strong alkali will cause microscratches, or etch invisible imperfections into larger ones, and change the optical characteristics.  You may be OK, if you limit the exposure, but it really depends on your application.  Acid, at the very least, doesn't have a significant effect on quartz, so that's a choice for you.

[rajan]

In saying that I use a new tube everytime because thats the law where I work.

i have some nochromix (all the cleaning, none of the chromium waste), but i think i'll try the dmso like you said. good suggestion, i hadn't thought of it.

Acid, at the very least, doesn't have a significant effect on quartz, so that's a choice for you.

that's what i was hoping to hear. thanks a lot guys

[gfunk]

Yeah, make sure you don't use chromic acid on NMR tubes!  Residual chromium on the tubes = bad news for NMR.  I don't think Russell meant use DMSO for cleaning; that'd be an interesting situation...  For stubborn tubes, you can use aqua regia (3:1 conc HCl:conc HNO3).  Rinse with DI water, and leave them to dry.  It should be fine to leave the NMR tubes to dry on lower heat (50*C or so) lying on their side for shorter periods of time.

If you have lots of NMR tubes to wash, it's handy to get an NMR tube washer.  They're expensive, but you can make your own for cheap.  I have 50+ NMR tubes to wash next week and I'll be making good use of the NMR tube washer!

Oh, and I heartily second the washing NMR tubes after you're done with them.  Makes life a lot easier.  But I tend to forget that.  As a pre-wash step, I fill NMR tubes with solvent and sonicate, then use the washer.

[rajan]

I don't think Russell meant use DMSO for cleaning; that'd be an interesting situation

D'OH