If these are in ppm level you can very well use HPLC method , anion exchange column, conductivity or UV detector. If these in ppb level you may need t go for LC/MS technique which is capable of quantifying down below 50 ppb level

Kidney International (1998) 53, 1348–1352; doi:10.1046/j.1523-1755.1998.00891.x

Simultaneous determination of oxalate, citrate and sulfate in children's plasma with ion chromatography

Technical Note

Bernd Hoppe, Markus J Kemper, Michael G Hvizd, Dawn E Sailer and Craig B Langman

Division of Pediatric Nephrology, Northwestern University, Children's Memorial Hospital, Chicago, Illinois, USA, Division of Pediatric Nephrology, University Children's Hospital, Hamburg, Germany, Dionex Corp., Westmont, Illinois, USA

Correspondence: Craig B. Langman, M.D., Division of Pediatric Nephrology, Children's Memorial Hospital, 2300 Children's Plaza #37, Chicago, Illinois 60614, USA. E-mail: [email protected]

Received 9 September 1997; Revised 26 November 1997; Accepted 26 November 1997.

Hi,

I would say use LC-MS, its the simplest method and at max will take 20 mins per sample. You can determine all these metabolites together in one injection.

Kind regards,

Charan