Determination of creatinine using pulsed amperometry

Tato diplomová práce se zabývá stanovením kreatininu pomocí kombinace průtokové injekční analýzy (FIA) a vysokoúčinné kapalinové chromatografie (HPLC) s pulsní amperometrií, elektrochemickou technikou založenou na vkládání potenciálových pulsů na zlatou pracovní elektrodu. Stanovení probíhalo v zásaditém prostředí borátového pufru s roztokem kreatininu o koncentraci 1∙10-4 mol∙l-1 . Byla optimalizována délka čistícího a aktivačního pulsu a pH nosného roztoku. Na elektrodu byl nejprve vkládán čistící puls o velikosti +1,8 V po dobu 100 ms, dále byl vkládán aktivační potenciál -0,5 V po dobu 150 ms a poté měřící potenciál +0,2 V po 300 ms. Z proměřených pH bylo vybráno optimální pH=9,4. K borátovému pufru byl přidán methanol a později i acetonitril, aby bylo vyzkoušeno, zda je možné s těmito organickými rozpouštědly stanovovat kreatinin a zda bude možné průtokovou injekční analýzu nahradit metodou HPLC. Methanol v systému způsoboval deformaci píků, acetonitril v systému nezpůsoboval deformaci píků, při vyšším obsahu docházelo k destabilizaci základní linie. Dále byla proměřena kalibrační závislost v rozsahu koncentrací od 2,5 ∙ 10-4 mol∙l-1 do 5 ∙ 10-6 mol∙l-1 pomocí PAD v kombinaci s FIA. U vyšších koncentrací docházelo k rozdvojení píků. Pomocí PAD s HPLC byl proměřen samotný kreatinin o...This diploma thesis deals with the determination of creatinine using a combination of flow injection analysis (FIA) or high-performance liquid chromatography (HPLC) with pulse amperometry, an electrochemical technique based on the application of potential pulses on a gold working electrode. The determination was performed in a basic environment of borate buffer with creatinine concentration of 1∙10-4 mol∙l-1 . The lenght of the cleaning and activation pulse was optimized as well as the pH of the running buffer. A cleaning pulse of +1.8 V was first applied to the electrode for 100 ms, then an activation potential of -0.5 V was applied for 150 ms and then a measuring potential of +0.2 V for 300 ms. The optimal pH was selected as pH=9,4. Methanol and acetonitrile were added to the borate buffer to test whether creatinine could be determined in presence of these organic solvents and whether flow injection analysis could be transformed into HPLC. Methanol in the system caused peak deformation, acetonitrile did not cause the peak deformation in the system, at higher contents the baseline was destabilized. Furthermore, the calibration dependence in the range of concentrations from 2.5∙10-4 mol∙l-1 to 5∙10-6 mol ∙ l-1 was measured using PAD in combination with FIA. At higher concentrations, peaks splitted....Department of Analytical ChemistryKatedra analytické chemiePřírodovědecká fakultaFaculty of Scienc

Influence of the pulsed amperometric detection on the passivation of working electrode

Department of Analytical ChemistryKatedra analytické chemiePřírodovědecká fakultaFaculty of Scienc

Determination of creatinine using pulsed amperometry

This diploma thesis deals with the determination of creatinine using a combination of flow injection analysis (FIA) or high-performance liquid chromatography (HPLC) with pulse amperometry, an electrochemical technique based on the application of potential pulses on a gold working electrode. The determination was performed in a basic environment of borate buffer with creatinine concentration of 1∙10-4 mol∙l-1 . The lenght of the cleaning and activation pulse was optimized as well as the pH of the running buffer. A cleaning pulse of +1.8 V was first applied to the electrode for 100 ms, then an activation potential of -0.5 V was applied for 150 ms and then a measuring potential of +0.2 V for 300 ms. The optimal pH was selected as pH=9,4. Methanol and acetonitrile were added to the borate buffer to test whether creatinine could be determined in presence of these organic solvents and whether flow injection analysis could be transformed into HPLC. Methanol in the system caused peak deformation, acetonitrile did not cause the peak deformation in the system, at higher contents the baseline was destabilized. Furthermore, the calibration dependence in the range of concentrations from 2.5∙10-4 mol∙l-1 to 5∙10-6 mol ∙ l-1 was measured using PAD in combination with FIA. At higher concentrations, peaks splitted...

Influence of the pulsed amperometric detection on the passivation of working electrode

Department of Analytical ChemistryKatedra analytické chemiePřírodovědecká fakultaFaculty of Scienc