Pharmaceutical Analysis By Nonaqueous Capillary Electrophoresis Coupled With Electrochemiluminescence Detection

Nonaqueous capillary electrophoresis (NACE) is refer to the operation ofelectrophoresis in organic solvent. Compared with aqueous capillary electrophoresis(CE), NACE produces lower electrophoretic current, more simple preparation ofsample and has better compatibility with electrochemical (EC) detection. It can beused to separate neutral compounds, hydrophobic and insoluble species which canhardly completed in aqueous CE. Electrochemiluminescence (ECL) involves thegeneration of production at electrode surfaces that then under electron-transferreactions to form excited states which emit light. The ECL of Ru(bpy)32+is widelyused because of the good solubility, stability and reutilization both in water andnonaqueous solvent. Here, the ECL for NACE (NACE-ECL) was presented for thepharmaceutical analysis with tertiary amine:1. Firstly, we synthesized Ru(bpy)3(ClO4)2for ECL regent, compared withRu(bpy)3Cl2, without the existence of Cl-, the ECL intensity was notably enhanced.Then, NACE-ECL was first validated by tripropylamine (TPrA). With the addition of1mM TPrA, the ECL intensity was enhanced by400times. In addition, therepeatability of ECL response was good because the Pt electrode was not easilyfouled with using organic buffer solution. The synthesized ECL regent ofRu(bpy)3(ClO4)2has great potential for the identification and detection in CE.2. NACE-ECL/EC was used for the detection of TPrA. The relative ECLintensity of the system was linear with the concentration of TPrA in the range from5×10-9to1×10-5mol/L. The correlation coefficient and detection limit are0.9992and5×10-9mol/L, respectively. The fast separation could be achieved because of thechoose of shorten capillary (33cm) and voltage.3. NACE-ECL/EC was employed to analyze doxylamine succinate salt andpheniramine maleate salt. The results showed that when the organic buffer solutionwere DMF:ACN(40:60, v/v), the optimum separation was achieved.In addition, the electrochemical deposition of Cu2O microcrystals wasinvestigated at glassy carbon (GC) electrode. Different shapes of Cu2O microstructures from super-octahedral to octahedron and then to microspheres werefabricated by varying the deposition voltage. The possible growth mechanism wasalso discussed. The non-enzymatic glucose detection based on the as-prepared Cu2Omicrospheres modified GC (Cu2O-GC) electrode was also presented, and exhibitedhigh electrocatalytic oxidization toward glucose.