Here are some Web-based Isotope Pattern Caculators that I recently tracked down for a Usenet post:

Molmass (Java with downloadable ‘lite’ version)

http://www.oraxcel.com/projects/molmass/index.htm

ChemCalc

http://www.geocities.com/junhuayan/pattern.htm

SIS MS Tools

http://www.sisweb.com/cgi-bin/mass10.pl

Sheffield Chemputer

http://www.shef.ac.uk/~chem/chemputer/isotopes.html

For stand-alone there is Isopro for Windows http://members.aol.com/msmssoft/

and the Macintosh Isotope Pattern Calculator http://info-mac.acornsw.com/infomac/_SCIENCE_AND_MATH/ISOTOPE-PATTERN-CALC-166.HTML

The 16th International Mass Spectrometry Conference will be held in Edinburgh, Scotland, between August 31st and September 5th 2003. That’s still a long way off, but it’s worth bookmarking the 16th IMSC Web page at http://www.imsc-edinburgh2003.com/. There’s no link back to the International Mass Spectrometry Society on the page, so here it is: http://www.imss.nl/. Note that the IMSS site is on a Netherlands server and has a “.nl” rather than a “.com” or “.org” Web address.