123rd General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation of Young Analytical Chemists I
Room No. Room 202
Time THU 10:36-10:40
Code ANAL1.O-25
Subject Mechanism of trinitrophenol explosive detection with novel multiple emitting quantum dots coated with amphiphilic conjugated polythiophenes
Authors Sarvar Kakhkhorov, Salah Mahmoud Tawfik Ahmed1, Yong-ill Lee1,*
Changwon National University, Uzbekistan
1Department of Chemistry, Changwon National University, Korea
Abstract The novel type of multiple emitting CdTe quantum dots (QDs) coated with amphiphilic conjugated polythiophenes has been developed for the determination of the 2,4,6-trinitrophenol (TNP) explosive. Overall, four types of nanohybrids were designed based on the QDs coated with differently charged polythiophenes (cationic, anionic, and nonionic) and thiophene copolymer. The integration of QDs aimed to increase the electron density of polythiophenes which resulted in efficient interaction of the developed nanohybrids with electron-deficient TNP. This was confirmed by considerable fluorescence quenching of the developed sensors when their response to various types of nitroexplosives was studied: nitrophenols and specifically TNP caused the most remarkable fluorescence quenching compared to the other nitroaromatics. Among the developed nanohybrids, positively charged polythiophenes demonstrated the most efficient fluorescence quenching due to the attraction of –OH groups of TNP to the surface of such nanohybrids. The results of time-resolved fluorescence measurements revealed the presence of stating quenching through the formation of ground state electrostatic interactions which excludes the excited state energy transfer with Förster resonance energy transfer (FRET) mechanism and suggests the inner filter effect (IFE) as a reason of fluorescence quenching of the sensors. In addition, the contribution of hydrogen bonding, electrostatic, and π-π interactions formed between TNP and QD nanohybrids resulted in high fluorescence quenching of up to 96% as well as in the detection of ultralow amounts of TNP up to 0.56×10-9 M.
E-mail sarvarkakhkhorov@gmail.com