Dear all,
we have problems with nitrate extraction from water for nitrogen isotope 
analysis using ion exchange columns. We use BioRad AG1X8 ion exchange 
resin and we don't succeed to elute the nitrate quantitatively. For a 
water sample containing 10 mg NO3 we use 5 mL of the anion exchange 
resin, the dripping rate is approx. 1 L/h. To elute the nitrate we use 
in total 30 mL 3M HCl (in aliquots of 3 mL). This should be enough, but 
we recover less than 50% NO3. What could be the problem?

Many thanks for your help,
with kind regards,
Sonja Lojen

-- 
Doc. dr. Sonja Lojen
Odsek za znanosti o okolju - Department of Environmental Sciences
Institut J. Stefan - J. Stefan Institute
Jamova 39
1000 Ljubljana
Slovenia

Tel.: (+386 1) 5885 393
Fax: (+386 1) 5885 346