802 Vikas Kumar Verma, Kavita Tapadia, Tungabidya Maharana International Journal of Engineering Technology Science and Research IJETSR www.ijetsr.com ISSN 2394 – 3386 Volume 4, Issue 9 September 2017 Fluorescence Spectrophotometric Determination of 6- Thioguanine in Biological Sample Vikas Kumar Verma 1 1 Department of Chemistry, National Institute of Technology, Raipur, CG, INDIA Kavita Tapadia 1 1 Department of Chemistry, National Institute of Technology, Raipur, CG, INDIA Tungabidya Maharana 1 1 Department of Chemistry, National Institute of Technology, Raipur, CG, INDIA Abstract Present work describes the fluorescence spectroscopy determination of (6-TG) using silver nanoparticles (AgNPs). The acridine could be electrostatically adsorbed to the surface of the citrate-stabilized silver nanoparticles. Upon addition of 6-TG, the acridine is replaced from the surface of AgNPs which induce the aggregation of AgNPs. Under optimum condition, the fluorescence intensity enhance showed the linear relationships with 6-TG concentration range from 0.05 × 10 -8 M to 4.0 × 10 -7 M. The detection limits (3s) and % RSD for 6-TG was occurred to be 9.6 nM, ± 2 % respectively. Proposed work has been successfully applied for the determination of 6-TG in biological sample such as urine sample. Keywords- Fluorescence spectroscopy, silver nanoparticles, acridine, 6-Thioguanine. 1. Introduction 6-Thioguanine (6-TG) is similar to guanine which is one of the basic components of the nucleic acid [1,2]. Due to its chemotherapeutic properties 6-TG is often used as life saving drugs in acute myeloid leukemia and some other pathological condition [3]. The plausible dose dependent side effects include bone marrow depression [4]. For such health issues, numerous techniques are used like high-performance liquid chromatography (HPLC) [5], Surface-enhanced Raman scattering [6], mass spectrometry [7], localized surface plasmon resonance [8] etc. These methods have their own demerits and limitations due to complication time consuming, Costly and poor sensitivity. Thus for the determination of 6-thioguanine, a simple rapid method is required. Silver nanoparticles (Ag NPs) has been extensively used as highly sensitive fluorescent probe for the determination of biomolecules [9] and drugs [10] due to nanoparticles (AgNPs) are promising nonmaterial it can be employed in many applications because it exhibit unique optical, chemical and electronic properties. In present work the 6-TG was determined by use AgNPs as quencher tool for the fluorescence intensity. Acridine is an example of cationic dye, thus it adsorb to the surface of the citrate capped AgNPs through electrostatic interaction. Formation of an Acridine-AgNPs conjugate is preceded by neutralization of charge. 2. Materials and methods 2.1 Materials and instrumentation. All reagents used were of analytical grade. Silver nitrate (99.8%) purchased from Qualigen, Fischer Scientific, Mumbai, India, Acridine, trisodium citrate and authentic samples of 6 TG was purchased from Sigma Aldrich. The pH has been adjusted in 1.0 M concentration of Sodium hydroxide and hydrochloric acid. Fluorescence spectra of all of the samples recorded using a G9800A Fluorescence Spectroscopy. Absorption