Sorption mechanisms of the metal ions in single and

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Unformatted text preview: but was as a function of the conditioning reagent. 75 23rd-25th June 2010 3rd ICYC 2010 Universiti Sains Malaysia ANA-024 FLUORESCENCE UREA BIOSENSOR BASED ON WATER SOLUBLE ZnS QUANTUM DOTS 1,2 Eka Safitri, Lee Yook Heng and Musa Ahmad 1 1 School of Chemical Science and Food Technology, Faculty of Science and Technology University Kebangsaan Malaysia, 43600, Selangor 2 Chemistry Department, Faculty of Mathematic and Basic Science, Syiah Kuala University, Banda Aceh, Indonesia E-mail: ZnS quantum dots (QDs) were prepared from zinc nitrate and sodium sulfide under optimized composition. The emission wavelength of the QDs was influenced by sodium sulfide addition rate. The highest QD fluorescence intensity was obtained when the ratio of Zn:S=1:2. T ransmission electron microscopy (TEM) image showed that the particle sizes of the QDs were around 5 - 7 nm. After functionalized the QDs using mercaptopropionic acid (MPA) as a capping agent, the QDs became water soluble. Employing the free carboxyl groups of the MPA attached on the surface of ZnS QDs, bio conjugation of urease enzyme was carried out to construct a urea biosensor. The urease enzyme was successfully immobilized on the ZnS QDs surfaces. Upon reaction between urease and urea, a change of pH was observed and this affected the ZnS QDs fluorescence intensities. The urea biosensor response was optimum in 1 mM phosphate buffer (pH 7). The fluorescence intensity of the urease enzyme -1 -7 2 conjugated QDs changed linearly with urea concentrations between 10 M and 10 M (R = 0.9867). Thus, a biosensor based on ZnS QDs was successfully developed for direct detection of urea. 1 POSTER PRESENTATION (ANALYTICAL) ANA-P1 DEVELOPMENT AND VALIDATION OF A SIMPLE HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC METHOD FOR DETERMINATION OF KETOPROFEN IN HUMAN PLASMA Jiyauddin Khan, Kah Hay Yuen, Ng Bee Hong, Wong Jia Woei, Mallikarjun Chitneni, Gamal Osman Elhassan, Samer AL-Dhalli and Kaleemullah Mohammed School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Pu...
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