| Pharmaceutical analysis is an important means to guarantee medicines safe and effective,which had the prominent function in each link of drugs including research, production, usage,circulation and management. The main contents in pharmaceutical analysis include:characters, identification, tests and assay. Spectrophotometry is a common method forpharmaceutical analysis. It has a lot of advantages such as high accuracy, simple apparatus,convenient operation and fast speed when used in the identification, tests and assay of drugs.It is a method most in use to analyze drugs. Since 1980, pharmaceutical analysis has beendeveloped with the development of the organic reagents, and the original works wereobtained by the analysts in this period. At the same time, a lot of new spectrophotometrymethods were presented and these were used in the practical samples, such as flotationtechnology, multi-wavelength, flow-injection method and so on.According to the nucleophilic substitution reaction, the qualitative analysis andquantitative analysis methods for the determination of moroxydine hydrochloride,paracetamol, cefotaxime sodium, methanol, boron have been established using sodiumnitroprusside as chromogenic reagents in this paper. Bioavailability and metabolism curve ofdrugs have been analyzed by this method.This dissertation consists of six parts:Chapter 1: this part reviews the current state and advance of the pharmaceutical analysis,the sorts of the spectrophotometry methods, and the application of the spectrophotometrymethods in the pharmaceutical analysis.Chapter 2: A purple n-nitrosamine product is formed by the reaction of moroxydinehydrochloride and sodium nitroprusside in basic solution, the maximum absorptionwavelength is 508 nm, and the apparent molar absorption coefficient is 2.5×103 L·mol.1·cm.1.A good linear relationship of the concentration of moroxydine hydrochloride versusabsorbance is observed with a linear range of 0.38300μg·mL-1. The liner regression equationis A = 0.02292+0.01213C (μg·mL-1) with a correlation coefficient of 0.9998. The detectionlimit is 0.25μg·mL-1, and its relative standard deviation is 0.21%. Chapter 3: This experiment indicates that the sodium nitroprusside can react with theparacetamol in a basic solution to form a product with colored o-nitrosamines. The maximalabsorption wavelength and the apparent molar absorption coefficient of the product are 700nm, and 3.4×103 L·mol.1·cm.1. A Good linear relationship is obtained between the absorbanceand the concentration of paracetamol in a wide range of 0.1996μg·mL-1. The linearregression equation is A = 0.01695+0.02240C (μg·mL-1), with a correlation coefficient of0.9993. The detection limit is 0.10μg·mL-1, and its relative standard deviation is 0.90 %. Theparameters with regard to determination are optimized, and the reaction mechanism isdiscussed. This method has been successfully applied to the selective determination ofparacetamol in pharmaceutical and biological samples.Chapter 4: Colored nitrosamine product was formed by cefotaxime sodium and sodiumnitroprusside in alkaline solution. The liner regression equation is A=0.010 + 0.00816C(μg·mL-1) with a correlation coefficient of 0.9994, and apparent molar absorption coefficientwas 2.0×103 L·mol.1·cm.1 at 525nm. Beer's law is well obeyed in a range of cefotaximesodium concentration of 0.91200μg·mL-1, the limit of detection was 0.62μg·mL-1, therelative standard deviation was 0.20%. The method was used for the determination ofcefotaxime sodium in pharmaceutical samples and human serum with satisfactory results.Chapter 5: The method indicates that the sodium nitroprusside can react with themethanol to form a colored product in the basic solution. The absorbance of the product ismeasured at the maximal absorption wavelength of 481 nm, and the amount of methanol canbe calculated based on this absorbance. A good linear relationship of the concentration ofmethanol versus absorbance is observed with a linear range of 0.026.0 mg·mL-1. The linearregression equation is A = 0.02484 + 0.29457C (mg·mL-1), with a correlation coefficient of0.9991. The detection limit is 0.012 mg·mL-1, while its R.S.D. is 1.5% and the recovery rate is97.5102.5%. Analytical results obtained by this new method were very gratifying.Chapter 6: A novel method to determine boron with high selectivity and good sensitivityhas been established by using sodium nitroprusside as spectroscopic probe reagent. This studyindicates that the sodium nitroprusside solution will be discolored when boron is added to thesolution. And the addition of a little methanol will improve the discoloration. Beer's law isobeyed in the range of boron concentrations of 0.6120.1μg·mL-1 at the maximal discoloring wavelength of 459 nm. The equation of linear regression is A =–0.01645–0.0077C (μg·mL-1),with a linearly correlation coefficient of 0.9991. The detection limit is 0.36μg·mL-1 andR.S.D. is 1.0%. The parameters with regard to determination are optimized, and the reactionmechanism is discussed. The assay was robust for a variety of samples, includingpharmaceutical, food and biological samples.
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