Why titrate?

1 Comment

A chemistry teacher wanted to know why professional chemists carry out titrations …

Seriously though, why do chemists actually do #titrations? I want an exciting application to engage my #chemistry students #chemed

Tom Husband @rhymingchemist

I used to do this titration A LOT. Synthetic chemists need to titrate unstable reagents. https://t.co/2hIAFNdRe3
— Paul MacLellan (@insidecircles) October 20, 2016

Just to clarify, is that so that only the exact right amount is used because XS BuLi could be lethally dangerous?

Tom Husband @rhymingchemist

No - so you know how much you're using! BuLi obviously air-sensitive, so slowly goes off if bottle isn't used carefully.
— Paul MacLellan (@insidecircles) October 20, 2016

So if it's a month or two old, you need to titrate because it might be 1.0M now rather than 1.2M.
— Paul MacLellan (@insidecircles) October 20, 2016

I used to do 100s of Winkler titrations on a rolling ship, every day, for weeks on end! (measuring phytoplankton P:R ratios)
— Niki Kaiser (K Chem) (@chemDrK) October 20, 2016

is this measuring oxygen levels? What’s the P:R ratio?

Tom Husband @rhymingchemist

yep. Measures dissolved oxygen concentration. P:R is Production: Respiration. So by incubating seawater in light/ dark, and
— Niki Kaiser (K Chem) (@chemDrK) October 20, 2016

measuring O2 concs before/after incubations, you could calculate P/R rates. https://t.co/RvHMuFS2rk
— Niki Kaiser (K Chem) (@chemDrK) October 20, 2016

100s of titrations on rolling seas, deck incubations, 3am starts, flying fish & big yellow rubber trousers made this https://t.co/RvHMuFS2rk
— Niki Kaiser (K Chem) (@chemDrK) October 20, 2016

Need to make the connection to something happening in the real world. Lead in the water in Flint, MI, perhaps.
— Stephen Davey (@stephengdavey) October 20, 2016

Like it! A passionate political struggle to engage their attention

Tom Husband @rhymingchemist

Lots of background here https://t.co/gNViEiihQq
— Stephen Davey (@stephengdavey) October 20, 2016

understanding material growth. In my area we are trying to understand biomineralisation - titrations are done all the time.
— A Finney (@aaronrfinney) October 20, 2016

we do them on in the Library of Congress to check paper pH & deacidification, prevent degradation

Andrew Davis @weemadandrew

a friend of mine used to do them because he was a specialist in rare metals for currency trading (v weird I know!)
— Kristy Turner (@doc_kristy) October 20, 2016

@rhymingchemist I've seen them done with OJ quality control... not sure why though
— Sean Fisk (@mrfiskteach1) October 20, 2016

@rhymingchemist medicine too. Quality control of prescription and OTC drugs.
— Sean Fisk (@mrfiskteach1) October 20, 2016

@rhymingchemist water quality too. Used to do Winkler titrations on water samples from Tampa Bay, though a DO probe is faster now.
— Sean Fisk (@mrfiskteach1) October 20, 2016

@rhymingchemist water analysis (composition for medical purposes), fine motor skills and cos it makes other techniques look interesting
— Katherine Haxton (@kjhaxton) October 20, 2016

For example to in-situ determine the amount of grignard reagent created

TRSolebumAlex @TRSolebum

Thanks, to clarify, you’ve used one (set of) rxns to generate a reactant for another rxn and you’re measuring how much you have?

Tom Husband @rhymingchemist