CE with a new electrochemiluminescent detection system for separation and detection of proteins labeled with tris(1,10‐phenanthroline) ruthenium(II)

In this article, a CE with a new electrochemiluminescent (ECL) detection system was developed. A microfluidic ECL detection cell with less than 0.5 microL dead volumes was developed and used as detector for this system. A hydrofluoric acid-etched porous joint was made at 8 mm from the outlet of the separation capillary to isolate the CE high voltage from ECL detection. The proposed CE-ECL system was applied for separation and detection of some proteins labeled with tris(1,10-phenanthroline) ruthenium(II). High efficiency ECL-enhanced reagent, tripropylamine, was infused to the detection cell as coreactant by a micro-infusion system to obtain maximum and stable ECL signal. The performance of this setup was illustrated by the analysis of tris(1,10-phenanthroline) ruthenium(II)-labeled proteins. The background electrolyte for protein detection was 20 mM Tris-CH3COOH with 2.0% m/m PVP at pH 4.0. Under the optimal conditions, the corresponding LOD were 2.2 x 10(-10) M for HSA, 4.4 x 10(-10) M for casein (alpha-S1) and 5.1 x 10(-10) M for cytochrome c. The proposed method was also successfully used for the trace analysis of albumin in human urine without any pretreatment.