Spectrophotometric Determination of Glutathione and Cysteine Based on Aggregation of Colloidal Gold Nanoparticles

, M.Sc. Thesis Sharif University of Technology Seyyed Hosseini, Ensieh (Author) ; Hormozi Nezhad, Mohammad Reza (Supervisor)

Abstract

low-molecular-weigth aminothiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) play a critical role in many biochemical pathways . Their level in biological fluids such as human plasma and urine are important for clinical diagnostics of a variety of diseases.
We report herein the development of a highly sensitive colorimetric method for detection of cysteine and glutathione using the citrate capped gold nanoparticles (Au-NPs). This thiol containing molecules exhibit intriguing reactivities with Au nanoparticles. The reactivity involves the displacement of the citrate shell by the thiolate shell which is followed by intermolecular electrostatic interactions or...

Modeling of Reactive Crystallization Processes

, M.Sc. Thesis Sharif University of Technology Rafiei Shishavan, Mina (Author) ; Shahrokhi, Mohammad (Supervisor)

Abstract

This thesis concerns the modeling of precipitation processes aimed at predicting product particle characteristics especially particle size distribution. A mixing-precipitation model (based on SFM) linked to the population balance is used for a single-feed semi-batch precipitation process to describe the mixing effects on the final particle-size distribution (PSD) and mean size, considering the agglomeration mechanism. The model describes mixing on two zones: the feed and bulk zone with different levels of super saturation. To solve a full population balance equation containing nucleation, growth and agglomeration, discretization method was performed witch is more accurate and low...

Colorimetric Determination of Tizanidine and Mercury (II) Based on Aggregation and Anti-aggregation of Gold Nanoparticles

, M.Sc. Thesis Sharif University of Technology Yahyazadeh, Ehsan (Author) ; Hormozi Nezhad, Mohammad Reza (Supervisor)

Abstract

In the first section of this research, we have developed a simple and rapid colorimetric method for determination of tizanidine using citrate capped gold nanoparticles. Under optimal conditions, the AuNPs easily aggregate upon addition of tizanidine and the solution color changes from red to gray. This color change was followed using a UV-Vis spectrophotometer. The detection limit was calculated to be 0.48 µM. The method was successfully applied for determination of tizanidine in Spalex© tablets. In the last section, the anti-aggregation effect of Hg(II) on the tizanidine-AuNPs system was utilized with the aim of developing a colorimetric method for detection of Hg(II). Addition of...