[kamiyu]

Hi there

I am asking about the washing of cuvette (quartz) used for absorption and emission.

Of course, I can use ordinary solvent such as DCM, acetonitrile, methanol etc.

But can I use:

1) conc. nitric acid?

2) conc sulphuric acid?

I know base bath fails definitely.

Any other drastic cleaning protocol?

Thanks

[Arkcon]

It really does depend on the manufacturer of the cuvette.  Most of them are bonded with some sort of glue that will be attacked with a long soak in any strong solvent.  A rinse with moderate strength acid will probably be all right.  What reagents are you using that need concentrated nitric and sulfuric acids?  How are you rinsing.  Because it seems a weird image for me -- you have a cuvette washer, and a bottle of sulfuric acid "syrup" or fuming nitric, you squirt it in and hen let it flush the cuvette?  And then rinse with water?  Its going to get hot, droplets of water added to droplets of acid.  Then what, acetone rinse?  Seems like such a bad idea.

[kamiyu]

Indeed, I try my best to clean the cuvette because my stuff is only weakly emissive and any trace strongly emissive stuff (used by previous user) may have big big error in my measurement.

I plan just use a pipette to rinse the cuvette and wash it with water then acetone and methanol and DCM

[Corribus]

I have cleaned out good quality quartz cuvettes with concentrated nitric acid. Nitric is a good choice because it's also an oxidizer. However as a general rule we limited soak times to just a few minutes. This is not something we did on a route basis - just for when the cells were very visibly dirty and couldn't be cleaned with standard solvents.

[FireflySci]

Hi everyone, sorry to necro post on this, but I just joined the forum today and I would like to weigh in on this one.  The type of "glue" that everyone is talking about is called glass frit, you can read about in on this site:  http://www.fireflysci.com/news/2015/7/16/can-a-uv-celluv-cuvette-be-repaired, near the bottom is a section about fritting cuvettes. 

You never want to use conc sulfuric acid to clean a cuvette.  This can distort the quartz and ruin your cuvette.  In this article there is a great cleaning guide for removing the toughest stains and dirt from a cuvette: http://www.fireflysci.com/news/2015/6/11/rare-shimadzu-16-cell-microcuvette-available.

Here's to your success!
Simcha

[Babcock_Hall]

Some years ago I learned of a recipe that was attributed to Beckman, which was 50% 3 M HCl and 50% ethanol (probably measured by volumes).  I just Googled a bit and found this passage from Beckman with respect to cleaning microcells:  "For other hard-to-remove deposits, wash with a solution made from
equal parts by volume ethanol and 3N HCl. Rinse the cell immediately with distilled water, air dry and store. Do not soak the cell in this solution for more than 30 seconds."

I am surprised that they do not recommend soaking for longer than 30 s.

[FireflySci]

Hi Babcock_Hall.  Thanks for the formula, I'm going to recommend my colleagues try this out.