Determination of oxalate in human serum by multicolumn isotachophoresis

The practical usefulness of multicolumn isotachophoresis was demonstrated by the determination of oxalate levels in human serum. 10 mmol/L HCl and 100 mmol/L Na2HPO4 served as the leading and terminating electrolyte, respectively. For the stabilization of the isotachophoretic zones in large cross section channels a suspension of Bio-Gel P-300 in the leading electrolyte was used. For the analysis ca. 1 mL of fresh serum was required and 1.2 mL of 1:1 mixture of serum and the suspension of Bio-Gel P-300 in deionized water was applied as sample. The time of analysis ranged between 45-49 min. The detection limit of analysis was determined to be 50 nmol/L. Reproducibility of analysis of 1 mumol/L oxalate in water standard was found to be 2.6% (n = 6).