Hi Robin, Though I haven’t heard from you, I thought my suggestion might still prove helpful; if not for you then for colleagues facing similar problems. Unless one wishes to go for maximum bang for one’s effort (exchange correction and scale normalization in one go), the situation you are facing can be solved without a keratin standard with a true, non-ex d2H value of about +60 ‰. The keratin standards you are using are perfectly adequate to deal with correction for exchangeable hydrogen based on the comparative equilibration method using 100 % matrix matched standards. Scale normalization of measured d2H values can be achieved in a separate step by including reference waters in silver tubes such as USGS48 and USGS49 as part of the batch run; these reference waters are available from the Reston lab. https://isotopes.usgs.gov/lab/referencematerials.html Best, Wolfram From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Robin Trayler Sent: 05 September 2018 17:00 To: [log in to unmask] Subject: [ISOGEOCHEM] High δD keratin reference materials Hi Everyone, Our lab has been measuring hydrogen isotopes on bird claws recently that fall well outside the range of our current reference materials. We currently use two keratin reference materials (CBS, δD = -197 and KHS, δD = -54.1‰) when running feathers and claws. Some of the claws we’ve analyzed have had δD values as high as + 50 to 60‰. Is anyone aware of any keratin reference materials that have δD around + 50 to +70‰? Best, Robin B. Trayler Stable Isotope Laboratory Department of Geosciences Boise State University, Boise, ID ________________________________ This email has been scanned for spam and viruses by Proofpoint Essentials. Click here<https://eu1.proofpointessentials.com/index01.php?mod_id=11&mod_option=logitem&mail_id=1536163288-2jV4Hp21NTAz&r_address=w.meier-augenstein%40rgu.ac.uk&report=1> to report this email as spam. ________________________________ Robert Gordon University has been awarded a TEF Gold award for the quality of its undergraduate teaching and learning, placing it in the top 20% of Universities in the UK Robert Gordon University, a Scottish charity registered under charity number SC 013781. This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of Robert Gordon University. Thank you.