Chromatography Forum

What is the appropriate solution to use for soaking glass pipettes that are awaiting washing? I am referring to class A pipettes for use in an analytical chemistry lab.

Thanks

We plop ours into a siphon washer (tips up) filled w/ DI and either an Alconox tab or some Chemsolve (the later being preferred).

That said, it somewhat depends on what sorts of things you're pipetting...

We plop ours into a siphon washer (tips up) filled w/ DI and either an Alconox tab or some Chemsolve (the later being preferred).

That said, it somewhat depends on what sorts of things you're pipetting...

Concurred,

Same for us.

Mind you, I remember the bad old days when a lab supervisor used to make us clean the glass pipettes with Chromic acid

I used to use chromic acid to clean out clogged Hamilton syringes (back in my acedemic days).

I used to use chromic acid to clean out clogged Hamilton syringes (back in my acedemic days).

God, I used to hate claning those clogged syringes. Then I wised up and started buying the RN models and discarding needles

Sodium chromate is carcinogenic. Don't even think of it.

That is why it isn't used anymore. Try dumping that solution down the drain and watch the Black Helicopters start to circle your location !

Think of all the people who live downstream from you.

Use the soap solution for a good general answer to your needs.

best wishes,

Rod

And, if you are lucky like I am, you will see the soap all over your chromatogram. That´s why I just use HPLC solvents or con. acids (H2SO4, HNO3, HCl) or NH4OH. If that doesn´t do it I don´t use the glassware (pipettes) for HPLC any more.

Your experience has been shared by others.

I have used conc H2SO4 to clean glassware but one has to watch for stressing the glass if there are any tiny scratches.

Rinsing the pipettes immediately after use is the best policy.

Of course, it depends upon the solution being used as to the best cleaning solution, pardon the pun.

best wishes,

Rod

We do not use soap when washing mobile phase containers. Using soap in a mobile phase container will get a old HPLC column thrown at your head.

With the high resolution instruments, I purchase new 2L glass bottles every few weeks and give the older bottles to the departments that can use them. I only use Optima grade solvents from Fisher-Sci or the equivalent. It is interesting what you can detect in normal grade Acetonitrile or Methanol.

I believe it actually depends on what was placed in the pipette. My professor told us to rinse pipettes with the use water and soap for chemicals that won't clogged up when mixed with H20. We only use chromic acid for those that could possibly stain the pipette.

you've all made me sooo happy. I hate hate hate hate soap. I hate it with a vengeance,. OK, I'll admit I use it at home, all the while, if nothing else to avoid social problems. But in the lab, anywhere within 100m of my LC solvent bottles, I hate it. I have a coworker who has a squeezy gun filled with soap that he Sprays At Things. It gets everywhere. Is it grounds for Justifiable Coworkercide?

Hi
I hated soap too in the lab. We use solution of "TEGO" to clean sinks and lab surfaces. I had a colleague who apparently had once spilled chromic acid on his finger - it wasn't a pretty sight - no fingernail grew again....
Pretty much weigh stuff out with disposable plastic pipettes into vols. these days - which are suitable for my samples.
Soap leaves a slippery residue every time.
WK