IR-MS N15 detection - standart

[postif]

hello my friends;

i need an information on N15 isotope value detection with EA-IRMS.

we want to carry out N15 ratio analysis with Thermo IRMS equipment. and i dont know which referans standart is suitable for us.

we use sucrose for C13 std which is known -10,6.

But we dont have std which is known for N15.
in the equipment pack, we have some std which are; acetanilide and cyclohexane. But we dont know the N15 values.

consequently, which referans standart do you recommend for N15 ratio value analysis?

Thank you

[jerole]

Have a look here: http://www.ciaaw.org/Nitrogen.htm

They have different reference materials for 15N.