My experience is that when you add paraformaldehyde to water all it forms is a colloidal solution (ie on standing, the paraformaldehyde settles with very little going into solution (personal experience, waited one week, then gave up).
Has your experience been different? Regards Tony Henwood JP, MSc, BAppSc, GradDipSysAnalys, CT(ASC) Laboratory Manager & Senior Scientist Tel: 612 9845 3306 Fax: 612 9845 3318 the children's hospital at westmead Cnr Hawkesbury Road and Hainsworth Street, Westmead Locked Bag 4001, Westmead NSW 2145, AUSTRALIA -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Sunday, 7 December 2008 7:30 AM To: histonet@lists.utsouthwestern.edu Subject: [Histonet] PFA preparation Hi, So then what is the best way to prepare formaldehyde fixative from PFA? The way I have been taught, which differs from what I have read, is to dissolve 4% into ddH2O at room temperature. After that one could add PBS or buffer. I've also been taught that too much heat during preparation "degrades" PFA, and that PFA (or formaldehyde solution, rather) stored too long will lose freshness because it "degrades." What I read is different. Texts suggest to dissolve the PFA in warm water, and that aging of the fix is due to repolymerization, not through degradation. What should i do? Eric Schmidt University of Calgary Medical Sciences _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet ********************************************************************* This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you are not the intended recipient, please delete it and notify the sender. Views expressed in this message and any attachments are those of the individual sender, and are not necessarily the views of The Children's Hospital at Westmead This note also confirms that this email message has been virus scanned and although no computer viruses were detected, The Childrens Hospital at Westmead accepts no liability for any consequential damage resulting from email containing computer viruses. ********************************************************************** _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet