End-column Electrochemiluminescence Detection Research Articles

Determination of Verapamil Hydrochloride and Norverapamil Hydrochloride in Rat Plasma by Capillary Electrophoresis With End-Column Electrochemiluminescence Detection and Their Pharmacokinetics Study.

In this study, we developed a new method for simultaneous determination of verapamil hydrochloride (VerHCl) and its metabolite norverapamil hydrochloride (NorHCl) by using the capillary electrophoresis-electrochemiluminescence. Under optimized experimental conditions, the linear ranges of the VerHCl and NorHCl concentrations were 0.015-10.0 and 0.060-10.0μg/mL, respectively. The linearity relations were determined using the respective regression equations y=581.2x+19.94 and y=339.4x+29.16. The respective limits of detection (S/N=3) were 0.006 and 0.024μg/mL. The proposed method was used to study the pharmacokinetics of both agents in rat plasma. The maximum concentration (Cmax), half-life time (T1/2) and time to peak (Tmax) were 683.21±74.81ng/mL, 0.52±0.21h and 2.49±0.32h for VerHCl and 698.42±71.45ng/mL, 1.14±0.26h and 2.83±0.23h for NorHCl, respectively, following oral administration of 10mg/kg VerHCl.

Simultaneous Determination of Tramadol and Diltiazem in Waterbodies by Capillary Electrophoresis with End-Column Electrochemiluminescence Detection

Simultaneous Determination of Tramadol and Diltiazem in Waterbodies by Capillary Electrophoresis with End-Column Electrochemiluminescence Detection

Determination of Tramadol in Human Serum by Capillary Electrophoresis with the End-Column Electrochemiluminescence Detection

A capillary electrophoresis (CE) coupled with end-column electrochemiluminescence (ECL) detection method for the analysis of tramadol (TMD) has been investigated. ECL detection was working electrode biased at 1.2 V in a 20mmol·L-1 sodium phosphate buffer (pH = 8.0) containing 5 mmol·L-1 Ru (where bpy = 2,2’-bipyridyl). Linear correlation (r ≥ 0.997) between ECL intensity and drug concentration was obtained in the range 3 × 10-4 - 6 × 10-6 mol·L-1. The limits of detection (LODs) for tramadol in water was 3.012 × 10-8 mol·L-1(S/N = 3). The relative standard deviation values on peak size (10-5 mol·L-1 level) and migration time for the tramadol were 4.58% and 1.39% (n = 10), respectively. Applicability of the CE-ECL method to the analysis of human serum spiked with tramadol was examined

Determination of imipramine and trimipramine by capillary electrophoresis with electrochemiluminescence detection

The tricyclic antidepressants (TCA) imipramine (Imi) and trimipramine (Tri) were successfully analyzed by capillary electrophoresis (CE) coupling with Tris(2,2-bipyridyl) ruthenium(II)-based (Ru(bpy)32+) end-column electrochemiluminescence (ECL) detection. The addition of β-CD to the running buffer was found to enable baseline separation of the two analytes and the addition of acetonitrile (ACN) as an organic additive to improve the repeatability and sensitivity of the CE method. Under the optimized separation and detection conditions (50mM PBS (pH=7.0) and 2mM Ru(bpy)32+ in the ECL detection cell, 20mM Tris (pH=2.0), 0.2mM β-CD and 20% ACN (v/v) as running buffer), wide linear ranges of 0.1–5μM and 0.1–5μM were achieved, with the correlation coefficients of 0.9990 (n=8) and 0.9980 (n=8) for Imi and Tri, respectively. Detection limits 5nM and 1nM (S/N=3) were obtained for Imi and Tri, respectively. The method was also successfully applied for the determination of Imi in pharmaceutical dosage form.

Determination of benzhexol hydrochloride by capillary zone electrophoresis with an end-column electrochemiluminescence detection

A capillary zone electrophoresis with end-column electrochemiluminescence (ECL) detector was described for the determination of benzhexol hydrochloride. The detection was based on the tris(2,2′-bypyridine)ruthenium(II) [Ru(bpy) 3 2+] ECL reaction with the analyte. Electrophoresis was performed using a 25 μm i.d. uncoated capillary. 10 mM sodium phosphate buffer (pH=8.0) was used as the running buffer. The solution in the detection cell was 80 mM sodium phosphate (pH=8.0) and 5 mM Ru(bpy) 3 2+. A linear calibration curve of three-orders of magnitude was obtained (with a correlation coefficient of >0.999) from 1.0×10 −8 to 1.0×10 −5 M and the limit of detection was 6.7×10 −9 M ( S/ N=3). This just provides an easy and sensitive method to determine the active ingredient in pharmaceutical formulations.

A simple and low-cost electrochemiluminescence detector for capillary electrophoresis.

A simple and cost-effective electrochemiluminescence (ECL) detector for capillary electrophoresis (CE) has been developed. The detector was constructed by vertically gluing a 0.5 mL plastic sample vial onto a piece of 1.5 cm x 1 cm x 0.6 mm indium/tin oxide (ITO)-coated glass plate. End-column ECL detection was performed in a wall-jet configuration. Potential control of the ITO electrode was provided using a direct current (DC) battery. Tris(2,2'-bipyridyl)ruthenium(III) (Ru(bpy)3(3+))-based ECL reaction was used for sensitive detection of four trialkylamines (trimethylamine, triethylamine, tripropylamine, tributylamine) and two amino acids (proline, hydroxyproline). With 15 mM sodium borate (pH 9.5) plus 3.5 mM Ru(bpy)3(2+) present in the detection cell and the ITO electrode biased at 1.7 V (vs. platinum wire reference), the test analytes can be efficiently separated and sensitively detected by the developed CE-ECL system. Linearity (r > or = 0.995) over two orders of magnitude and an average number of theoretical plates of 160 000/m were generally obtained. Reproducibility on peak height and migration times (n = 42) was 3.3% and 1.2% for tripropylamine, and 2.4% and 1.5% for proline, respectively. The detection limits were in the range of 2-5 microM (1-2 fmol) for the test analytes.

New technique for capillary electrophoresis directly coupled with end-column electrochemiluminescence detection.

A new end-column electrochemiluminescence (ECL) detection technique coupling to capillary electrophoresis (CE) is characterized. A 300 microm diameter Pt working electrode was used to directly couple with a 75 microm inner diameter separation capillary without an electric field decoupler. The hydrodynamic cyclic voltammogram (CV) of Ru(bpy) 3 2+ showed that electrophoretic current did not affect the ECL reaction. The presence of high-voltage (HV) field only resulted in the shift of the ECL detection potential. The distance of capillary to electrode was an important parameter for optimizing detection performance as it determined the characteristics of mass transport toward the electrode and the actual concentration of Ru(bpy) 3 2+ in the detection region. The optimum distance of capillary to electrode was decided by the inner diameter of the capillary, too. For a 75 microm capillary, the working electrode should be placed away from the capillary outlet at a distance within the range of 220-260 microm. The effects of pH value of ECL solution and molecular structure of analytes on peak height and theoretical plate numbers were discussed. Using the 75 microm capillary, under the optimum conditions, the method provided a linear range for tripropylamine (TPA) between 1 x 10(-10) and 1 x 10(-5) mol/L with correlation coefficient of 0.998. The detection limit (signal-to-noise ratio S/N = 3) was 5.0 x 10(-11) mol/L. The relative standard deviation in peak height for eight consecutive injections was 5.6%. By this new technique lidocaine spiked in a urine sample was determined. The method exhibited the linear range for lidocaine from 5.0 x 10(-8) to 1.0 x 10(-5) mol/L with correlation efficient of 0.998. The limit of detection (S/N = 3) was 2.0 x 10(-8) mol/L.