Hi Matt,


Although we are running with a different brand of equipment, we reliably detect N down to 40ug all the time. The only reason that our C target is 10x higher is that we typically run with a helium dilution. If you only need 13C, can you use a method such as without a dilution or different open split position? We run C without dilution if we need to analyze something precious or limited like and ancient sample or NBS19 via EA.







From: Stable Isotope Geochemistry <[log in to unmask]> On Behalf Of Matthew Von Tersch
Sent: Tuesday, July 31, 2018 4:04 AM
To: [log in to unmask]
Subject: [ISOGEOCHEM] Low %C soil bulk isotope analysis - how much is too much?


Hi all, 


We have been asked to run some soil samples taken from a salt marsh in Australia, the majority of which are from the surface, but there are also some from a core. The samples have been dried and ground and analysed for TOC. 


Based on a requirement of 400 ug carbon per sample for our system (Sercon 20-22), some of the samples will require between 5 and 15 mg of soil per capsule. I spend the majority of my time working with collagen in the 1 mg range, so this venturing into the unknown.


For those of you working with soils, is there anything I need to be aware of when running this type of material for delta 13C, and how much material per capsule is too much?


Many thanks for any assistance.





Please note that I check emails only twice a day, so urgent or quick queries may be resolved more efficiently by telephone or face-to-face.


Mr Matthew von Tersch

BioArCh Laboratory Manager


Department of Archaeology - University of York

Room 229, Environment Building

Wentworth Way

York YO10 5DD


Tel: 01904 328282