Chromatography Forum

Can anyone point me to sources of standardised sample prep techniques? I am looking for basic stuff like how to use a volumetric flask, TD pipette etc. This may sound like a stupid question, it used to be assumed that these techniques and skills were learnt at college. Not so nowadays - for example, I had a trainee with a Masters in chemistry that had to be shown how to use a pipette. So I am looking for the most official or commonly used set of standard procedures for a reference. The USP has some information in CH31, but it does not cover everything.
Thanks
J

John, I agree with you, the quality of teaching of volumetric techniques is not good, or not getting through to students. At my company we evaluated a few commerical videotapes, but found they didn't address stuff like magnetic stirrers diring titrations, and in one the guy actually put the buret stand on the floor so he could fill it at lower than eye level (maybe he should've invented the stepstool). So we made our own videotape training, starting that even if you have the best instrumentation, poor volumetric techniques are still a MUST to obtain real results. We sent this to QC loactions, made them watch; found out one location used one pipet (without washing or rinsing) for all its samples. This eliminated an issue where HPLC injections from each vial were consistent, but could randomly be low or high due to incomplete mixing in the volumetric flasks before taking sample solution. This way also didn't offend any 20-year employees who may have bristled upon being shown in person how do do it correctly ("you've been doing this wrong for 20 years..."). Basically we found QC knocking the tips off pipets and burets to increase flow rate to save time (yes, that happened), not mixing volumetrics thoroughly "to save time", stuff like that. Really scary.

Hello John,

Here is an excellent link on laboratory techniques:
http://jchemed.chem.wisc.edu:8000/JCESo ... u/MENU.HTM

That is scary. I was exposed to some of that stuff in high school, had the rest beat into me in G-Chem lab (where everything was done 3x w/ T-Tests a standard part of the write up).

Thanks for all your replies. I am still looking for official national, international or compendial reference on these matters.

When you find it, could you post the info (or link) back here? I think this is a more general problem than many of us care to admit!

Good luck with the search. As you want formal protocols, you might be disappointed by the amount of nausea they may specify. The following may no longer be current, and it's solely based on recollections.

If you operate in a regulated environment, you should find the appropriate training/skill requirements, and create a simple training regime to demonstrate staff that staff using items meet those requirements. Volumetric glassware is usually done in the first week or two in a laboratory. All laboratory training programmes in regulatory environments should document the 3S stages - Shown, Supervised, Solo.

To create the training programme in the absence of industry guidance, you probably would need to review the ASTM documents, but akind glassware supplier might have simple summaries available, as Kimble used to have in their glassware catalogues.

The default detailed starting protocol for general labs used to be the methods defined by the American Society for Testing and Materials ( ASTM ) in their standards and specifications.

ASTM E 542 Standard practice for Calibration of Laboratory Volumetric Apparatus.

Then you have to review the specific specifications for the particular glassware, which should be on the equipment. the most general was:-

ASTM E694 Standard Specification for Laboratory Glass Volumetric apparatus,

However there are a range of others, E1154 Pipettors, E1157 Reusable Laboratory Glasware, E969 Transfer pipettes, E1293 Measuing Pipettes etc etc.

It's a long time ago since I had to do this, and the above mayno longer be best practice.

Please keep having fun,

Bruce Hamilton

Just back from vacation and then this. What particularily bothers me is that some of these things seem to be due to a deep rooted change in our societies. The kids don´t seem to see a great vision to which they can feel to contribute, via thinking about things and self discipline, etc. As an example of what I mean: One should not need to be tought that it is necessary to rinse glass apparatus. How it should be rinsed is a different matter. But, if it occurs to someone that this thing should be cleaned before using it again, he might ask about how to do it.

The kids don´t seem to see a great vision to which they can feel to contribute

True statement well put.
It's not just young people though and I don't think the problem origins solely from their lack of vision, but also from *us not providing a complete picture.

Us = supervisors, trainers, managment and corporations.