Miniaturization overcomes macro sample analysis limitations: Salicylate-selective polystyrene nanoparticle-modified optical sensor

Publication date: 1 May 2019

Source: Talanta, Volume 196

Author(s): Fatehy M. Abdel-Haleem, Elsayed M. Zahran

Abstract

Salicylate-selective polystyrene micro-optode is engineered using a mixed solvent method. The size of the particles (200–400 nm) and the distribution of the recognition components onto their surface were elucidated by transmission electron microscope and confocal fluorescence microscope. The polystyrene micro/nanoparticles are modified with thiourea derivative as ionophore, ETH 7075 as chromoionophore, and tridodecylmethyl ammonium chloride (TDMAC) as ion-exchanger. The response mechanism depends on the selective binding of the ionophore at the surface of the particles to salicylate. A concomitant protonation of the chromoionophore results in a decrease in the absorbance at the maximum wavelength, 535 nm. Enabling this sensing interaction at the micro-scale decreases the response time of the optode to be lower than 10 s the concentration range of 3–70 µM, with a detection limit of 2.1 μM. This microsphere sensing platform demonstrated excellent performance in the determination of salicylate in spiked urine samples and in pharmaceutical formulations. Further miniaturization of these micro-optodes promises in-vivo analysis of intracellular analytes.

Graphical abstract

from A via a.sfakia on Inoreader http://bit.ly/2Qkq6fr