SIMULTANEOUS DETERMINATION OF OXALATE, CITRATE AND SULFATE IN CHILDRENS PLASMA WITH ION CHROMATOGRAPHY

To improve our understanding of both diagnosis and treatment of diseas es of oxalate metabolism, we first set out Lo establish a new ion-chro matographic method to determine normal plasma levels of oxalate, citra te and sulfate from single plasma samples. In 50 infants and children (23 girls, 27 boys, aged 0.2 to 17 years) with normal renal function, blood was drawn in Li-heparin tubes, placed on ice and preserved immed iately with 40 mu l 1 M HCl/ml plasma in two ultracentrifugation steps . For measurement, plasma was injected onto an ion chromatography syst em with NaOH as the mobile phase. and then run as a linear gradient fr om 5 mM to 52.5 mM over 21 minutes. Analysis yielded measurable and re producible oxalate (6.43 +/- 1.06 mu M/liter), citrate (79.3 +/- 27.4 mu M/liter) and sulfate 235.0 +/- 85.3 mu M/liter) levels. without any age and gender specific differences. The least detectable plasma oxal ate level was < 0.3 mu M with a high reliability and reproducibility ( coefficient of variance 1.95 to 4.75%). In conclusion, we established a reproducible, precise method to determine the relevant plasma anions involved in mineral metabolism, which heretofore have not been easily measurable. Studies of diseases of oxalate and citrate metabolism are ongoing on the basis of the normal plasma values achieved this study.