<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Hi Esther,<div class=""><br class=""></div><div class="">You’ll probably get quite a few answers on this topic. The standard fixation buffer for formalin that I use is a mix of phosphate salts:</div><div class="">•Phosphate buffer mix (6.5 parts Na2HPO4 and 4 parts NaH2PO4) is till one of the best and can be purchased mixed to the correct proportions.<br class="">•Sodium β-glycerophosphate is also a useful buffer. </div><div class=""><br class=""></div><div class="">•Buffers (as for formalin) do not last for ever and formalin tested after 30 years had dropped to pH 4.<br class="">•If pH is a sensitive issue relating to the specimen, the pH may drop by 1 every 10 years or so.<br class=""></div><div class=""><div class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">With all good wishes, <br class=""><br class="">Simon Moore MIScT, RSci, FLS, ACR<br class="">Conservator of Natural Sciences and Cutlery Historian,</span><br class=""><br class=""><a href="http://www.natural-history-conservation.com" class="">www.natural-history-conservation.com</a><br class=""><br class=""><span></span><br class=""><span><img apple-inline="yes" id="6E1BAE9C-C5D1-4709-BC9F-4E953C90A6CE" src="cid:3543D570-FCD3-4F5F-B04C-2A6D3A8D9E27@home" class=""></span><span><img apple-inline="yes" id="E24D90A8-5C73-440A-AC09-14F447E06408" src="cid:44ED9140-C81F-497F-B52B-A41A76C7F679@home" class=""></span><br class=""></div><br class=""><blockquote type="cite" class="">On 12 Feb 2021, at 09:27, Esther Dondorp <<a href="mailto:esther.dondorp@naturalis.nl" class="">esther.dondorp@naturalis.nl</a>> wrote:<br class=""><br class="">Dear colleagues, <br class=""><br class="">I need your advice on what buffer to use to fixate a large eel in formalin. I have to order 10% buffered formalin but I get the question from the chemical company what buffer they should add. The pH should be around 7 I guess?<br class=""><br class="">Many thanks and best regards,<br class=""><br class="">Esther Dondorp<br class="">Senior Collectiebeheerder<br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><br class="">+31717519313 - -<br class=""><a href="mailto:esther.dondorp@naturalis.nl" class="">esther.dondorp@naturalis.nl</a> - www.naturalis.nl<br class="">Darwinweg 2, 2333 CR Leiden<br class="">Postbus 9517, 2300 RA Leiden<br class=""><br class=""> <br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><br class="">_______________________________________________<br class="">Nhcoll-l mailing list<br class="">Nhcoll-l@mailman.yale.edu<br class="">https://mailman.yale.edu/mailman/listinfo/nhcoll-l<br class=""><br class="">_______________________________________________<br class="">NHCOLL-L is brought to you by the Society for the Preservation of<br class="">Natural History Collections (SPNHC), an international society whose<br class="">mission is to improve the preservation, conservation and management of<br class="">natural history collections to ensure their continuing value to<br class="">society. See http://www.spnhc.org for membership information.<br class="">Advertising on NH-COLL-L is inappropriate.<br class=""></blockquote><br class=""></div></body></html>