| A capillary electrophoresis with electrochemiluminescence detection (CE-ECL) has potential application in analytical chemistry. In recent years, Tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)32+)-based ECL has become an important and powerful detection method for CE due to both the powerful separation capacity, high efficiency, short analytical time, minimum consumption of sample and reagents of CE, the high sensitivity and improved selectivity of ECL detection. So, the marriage of CE to ECL offers the merits with enhancing sensitivity, improving selectivity, and reducing cost. It is become a sensitive and efficient analytical technique. CE-ECL detection is widely used in various fields, such as pharmaceutical analysis, bio-analysis, food analysis, the separation and analysis of other samples.The thesis is concentrated on the development and improvement of CE-ECL separation and detection technique, exploring its extensive application in pharmaceuticals and biochemicals and establishing novel systems of CE-ECL for the determination of nitrogen-containing compounds, as described below:1. Amoxicillin in urine was determined by capillary electropherosis eletrochemiluminescence. The recovery of urine was 95.35%. Relative standard deviation was less than 2. 0% for 1.0μg/mL of amoxicillin (n=6). The linear range of determination was 0.001~5.0μg/mL. The detection limit (3σ) was 0.32 ng/mL. The excretion rate of amoxicillin in the urine of one healthy volunteer was thus assayed. The excretion amount of amoxicillin within 6 hours was 44.54% , The maximum urine concentration appeared at 1.0~1.5 hours after administration of Amoxicillin.2. A new method for the determination of selenomethionine in selenium-enriched yeast was developed using capillary electrophoresis (CE) coupled with electrochemiluminescence (ECL) detection. The effects of detection potential, concentration and pH of phosphate buffer, separation voltage, electrokinetic voltage and injection time on ECL intensity were investigated. Under the optimal conditions, the linear concentration of selenomethionine ranged from 0.001 to 0.5 mg/L with a correlation coefficient of 0.9996. The limit of detection (3σ) was 0.39μg/L. The recovery of selenomethionine in selenium-enriched yeast was 97.7 % on an average. This method is simple, quick, sensitive and reliable for the determination of selenomethionine in selenium-enriched yeast.3. Using acetaldehyde as the derivatization reagent, a novel method for highly sensitive detection of metformin hydrochloride (MH) was developed by capillary electrophoresis (CE) coupled with electrogenerated chemiluminescence (ECL) of Tris(2,2′-bipyridyl)ruthenium(II). The precolumn derivatization of MH with acetaldehyde was performed in phosphate buffer at room temperature. Under the optimized conditions: 1.25 V(versus Ag/AgCl) applied potential, 5 mM Ru(bpy)32+ and 50 mM phosphate buffer (pH7.5) in the detection cell, derivtization reagent for 1.356 mM acetaldehyde, derivtization reaction time for 120 min, derivtization reaction buffer for 0.3 M phosphate (pH 7.5), the running buffer (pH 10.5, 7.5 mM phosphate, 7.5 mM borate, 2 mMβ-CD and 6 mM Na2SO4), 8 kV separation voltage, 10 kV injection voltage and 8 s injection time, the ECL intensity and detection sensitivity of MH was more 120 times than that of without derivatization. The linear concentration of MH ranged from 0.01 to 15μg/mL (with a correlation coefficient of 0.9943). The detection limit was 2.3 ng/mL with a signal-to-noise ratio of 3.
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