From owner-cellbiol@net.bio.net Thu Dec 12 22:00:00 1996 Path: biosci!bcm.tmc.edu!news.msfc.nasa.gov!www.nntp.primenet.com!nntp.primenet.com!feed1.news.erols.com!news.bbnplanet.com!cpk-news-hub1.bbnplanet.com!cpk-news-feed1.bbnplanet.com!nih.gov!usenet From: bernard@elsie.nci.nih.gov (Bernard Murray) Newsgroups: bionet.cellbiol Subject: Re: Dissolving xanthine Date: 13 Dec 1996 02:29:20 GMT Organization: National Institutes of Health, Bethesda, MD Lines: 23 Message-ID: <58qf20$20l@light.nih.gov> References: NNTP-Posting-Host: ermintrude.nci.nih.gov X-Newsreader: WinVN 0.99.7 In article , raja@uvic.ca says... >I am having some problems with dissolving xathine in water at conc. 10 >mg/ml for tissue culture growth. It does not dissolve completely, even with >prewarm water. Can I dissolve it in other kinds of solvents ?. Could any >of you who know please tell me how to do that. >Many thanks in advance. Most xanthine derivatives dissolve in alkaline solutions - either water (if you are lucky) or methanol. Try dissolving it as best you can and then add a minimal amount of eg. 1 M NaOH until it dissolves completely. Hopefully you will not be adding enough of this to affect the final pH of your culture medium. Yep, just had a look at my ancient copy of the Merck Index and found that xanthine has a maximal solubility in water of < 0.5 mM and you are trying for ca. 66 mM. Merck says that xanthine is freely soluble in NaOH solutions and also in mineral acids so you might also try pushing the pH in the acid direction. Bernard Bernard Murray, Ph.D. bernard@elsie.nci.nih.gov (National Cancer Institute, NIH, Bethesda MD, USA) .