We have formerly used a lidded Heto waterbath with mercury column switching element (part nos. long lost) which successfully controlled to a few hundredths of a degree. It too had a scale of 0-100 degrees but was precisely adjustable - with patience.
If samples and standards are treated at the same time, does it matter if the temperature is exact?
All the best
> -----Original Message-----
> From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
> Behalf Of A. Schauer
> Sent: Wednesday, 21 July 2010 4:35 p.m.
> To: [log in to unmask]
> Subject: [ISOGEOCHEM] 25*C
> Hi all,
> 1) How do you obtain a controlled 25*C for phosphoric acid digestion
> of carbonate in your lab? My lab varies around 22*C. It seems as though
> most water baths with heating option only control from 5*C above ambient
> to 99*C. Do you use a chiller model then or are you lucky enough to have a
> lab that is 20*C? Please either outline your method if home-built or
> provide a part number and manufacturer for your bath.
> 2) How do I know that my 25*C will be the same as your 25*C?
> Thank you.
> Andrew Schauer
> Earth and Space Sciences
> University of Washington
> Seattle, WA 98195
> [log in to unmask]