Determination of proline and. hydroxyproline in human urine with capillary electrophoresis-electrochemiluminescence

A method of capillary electrophoresis (CE) with tris (2,2'-bipyridyl) ruthenium ( H) electrochemiluminescence (ECL) detection has been applied to the simultaneous determination of proline (Pro) and hydroxyproline (Hyp) in human urine. Under optimized conditions, such as detection potential at 1.18 V, electrokinetic injection at 10 kV for 10 s, seperation voltage at 20 kV, 10 mmol/L seperation buffer with pH 8.5, 5 mmol/L ru(bpy)(3)(2+) and 50 mmol/L phosphate buffer with pH 7.0 in the ECL cell, the linear ranges were 0.008 similar to 2 mmol/L for Pro with a correlation coefficient of 0. 997, and 0. 01 similar to 2 mmol/L for Hyp with a correlation efficient of 0.998. Detection limits for Pro and Hyp were 2 and 4 mu mol/L respectively. When the method was applied to determine free and total Pro and Hyp in human urine, the recoveries were between 96.4% and 99.7%, respectively.