by
lmh » Fri May 20, 2011 11:51 am
Can I put an academic-lab perspective on this? Many academic organisations are now enlightened enough to have some sort of QA department, and as a result, the balances will be checked once in a while. Probably there's some sort of policy on pipette checking too, though in my experience enforcement is usually weak, and the length of time between checks is long (6 months isn't uncommon in Universities so far as I can tell).
Pipettes are far, far, far, hugely less reliable than balances (one misplaced squirt of something corrosive, and they leak). 6 months is an awful lot of faulty data.
If people checked their pipettes, using their balance, on a daily (or even weekly) basis, they would be checking simultaneously the balance and the pipette (and their own technique!). Of course you can argue that both instruments might be equally wrong. You can also argue that a pipette isn't good enough to check the balance - and you're right. But think what the balance is used for: usually, for preparing solutions, where the volume may well be added by pipette or by glassware that is (in Uni labs with chipped plastic) only slightly better than a pipette. Slight inaccuracy in the balance is probably going to be masked completely by bigger errors in the volumetric side of things. So a simple check of pipette versus balance would, in academia, probably save a lot of dubious work from reaching publication. But of course many academic scientists are far too busy to check pipettes.
