Investigation Of Oscillographic Behavior And Its Application For Several Medication

The oscillographic behaviors and its application of several medications were studied in this thesis. This investigation is very useful for probing the oscillographic mechanism of medication, broadening the range of oscillographic analysis and developing analytical methods for medication. This thesis consisted of four chapters, and main contents are as follows:l.The oscillographic behaviors of erythromycin and gemfibrozil were studied, and second order differential simple oscillographic voltammetry for the determination of erythromycin and gemfibrozil was founded. Experimental results showed that there are two incisions of erythromycin at -1.52V and -1.36V on the cathodic branch of d?dt - E curve in different pH solution. Once erythromycin is added into 0.2 mol/L NaOH, an incision at -1.52V appeared immediately on the oscillogram, and the incision depth decreased gradually and disappeared eventually with increase of time, whereas a new incision at -1.36V appeared and reached a stable height. The whole process could be observed on the screen of cathode ray oscillograph. The mechanism of two incisions was investigated by comparing with ultraviolet spectrography and cyclic voltammetry, which is likely to be caused by the reduction of erythromycin and its hydrolysate in strong alkaline solution. The study showed that oscillographic chonopotentiometry could be applied to monitoring the process of some chemical reactions.2. Two irreversible incision of berberine were observed on the cathodic branch of dE/dt - E curve in 0.2mol/L HsBOs - 0.2 mol/L KCI solution, and the incision potential was -1.49V and -1.78V, respectively. Based on the oscillographic characteristic of the first incision, second order diffenrential simple oscillographic voltammetry for the determination of berberine in capsule was founded. The linear range and detection limit for berberine was 1.3X10"6 ~ 1.0X10"5 mol/L, and 1.0X10"6 mol/L, respectively. The relative standard deviation and the average recovery in thesample was 1.5%(n=5) and 100.8%, respectively. Moreover, the mechanism of two incisions was investigated by comparing. The experimental results investigated with oscillographic method, single sweep poloragraphy and cyclic voltammetry showed that the first incision (-1.4 9V) was related to the strong adsorption of reductive production, and another (- 1.49V) was related to the diffusion of reactant.3. Based on the oscillographic characteristic of genistein and puerarin, second order differential simple oscillographic voltammetry for the determination of genistein and puerarin in medication was founded. The linear range was 3.0* 10~6 ~ 4.4* 10~5 mol/L and 2.5X10"6 - 3.5X10"5 mol/L, respectively. The detection limit for genistein and puerarin was 1.5x10"* mol/L and 1.2 X10"6 mol/L, respectively. Compared with other methods, simple oscillographic voltammetry with second order differential was a convenient method due to its cheap equipment and rapid measurement.4. The oscillographic behavior of the cooperation formed between rutin and Cd2+ was investigated in 0.05 mol/L Na2B4O7 - 0.05 mol/L KNOa buffer solution, and the oscillographic behavior was compared with single sweep poloragraphy and cyclic voltammetry. The experimental results showed that the incision caused by the cooperation at -0.75V of the cathodic branch on dE/dt-E curve has adsorption property. The oscillographic characteristic for the cooperation can be applied to the determination of Cd2+, rutin and A13+, respectively. The linear range for the determination of Cd2+, rutin and A13+ was 2.4*10"6 ~ 3.5*10'5 mol/L, l.QxlO"6 ~ S.OxlO"5 mol/L and 1.8*10"6 mol/L ~ 1.2x10"" mol/L, and the detection limit was 1.2X10"6 mol/L, 6.0xlO"7 mol/L and 6.0xlO"7 mol/L, respectively.