Studies On Sequential Injection Coupled With Spectrophotometry For The Determination Of Urinary Creatinine And Dipyrone

In this dissertation, the sequential injection analysis coupled with spectrophotometric technique was proposed and applied to the determination of urinary creatinine and dipyrone in sample.The first section of the dissertation introduced the metabolism of creatinine in the human body, the clinical significance of determination of creatinine and the progress of analytical methods for the determination of creatinine in recent years. The methods including chromatography, mass spectrometry, capillary electrophoresis, biosensor and spectrophotometry were introduced in detail. The paper also described the features of sequential injection and online dilution technology and their practical application.The second section of the dissertation described a sequential injection online dilution coupled with spectrophotometry in determination of creatinine in urine samples. The proposed method was based on classical Jaffe reaction of creatinine with alkaline picrate to form a colored product. When the sample was determined with sequential injection manual dilution, the absorbance was proportional to the mass concentration of creatinine in the range of 0.5～ 400 mg/L with a correlation coefficient of 0.9987. The relative standard deviation (RSD) for 11 repeated measurements was 1.6% at 100 mg/L levels. The sampling frequency was 11 samples per hour. When determined with sequential injection online dilution, under the optimum condition, the linear response range was 10～1000 mg/L with a correlation coefficient of 0.9991. The relative standard deviation (RSD) for 11 repeated measurements was 1.2% at 200 mg/L levels. The sampling frequency was 22 samples per hour. The proposed method utilized online dilution technology to achieve online sample pretreatment and overcome the fault of poor precision in manual operation, and there was no significant difference when compared with manual dilution.The third section of the dissertation, a fast sequential injection system with spectrophotometry detection for the determination of dipyrone in pharmaceutical formulations was proposed. At room temperature, dipyrone reacted with Fe3+ in acid medium to produce a blue complex which could make a characteristic absorption. The absorbance was proportional to the concentration of dipyrone in the range 0.01～1.2 g/L. The detection limit (3 σ/s) was 2.0 mg/L. The repeatability was estimated by repetitive injection (n = 11) of 0.4 g/L dipyrone, the relative standard deviation was 2.2%. The sample throughput of successive determination was 126 samples per hour. The method was applied to the determination of dipyrone in the pharmaceutical formulation and urine sample, the recovery was over 92.8% ～ 105.7%. The determination result of the proposed method was in agreement with that of the standard method, results of the significant test proved the reliability of the method.