Blue florescent carbon nanoparticles as sensor probe and paper based microfluidic device for Hg2+ ion detection.

Abstract

This study reports the application of fluorescent blue carbon nanoparticles as a sensing probe for the detection of Hg²⁺ ion on microfluidic paper based device (μPAD) as well as in aqueous medium. Florescent blue carbon nanoparticles are synthesised from waste sweet potato peels through a facile one-step hydrothermal method. The development of the microfluidic paper-based device (μPAD) is carried out by using Whatman 42 filter paper through laser engraving technique. For aqueous medium detection, the fluorescence spectra of carbon nanoparticles are analysed in presence of various concentration of Hg²⁺ ions. MATLAB R2023b is used for the study of the fluorescence colour variation to show precise and acceptable results of detection on paper based device. The Limit of detection for both the sensing routes are evaluated and found to 1.54 ppb for μPAD and 2.48 ppb in aqueous medium. The results demonstrated that the proposed μPAD sensor can show accuracy and precision agreement with standard florescence sensing in aqueous medium. The developed μPAD can also perform complicated analyses involving multiple steps reactions in a single step by using very small amount of analytical sample. Beside this, fluorescence colour intensity of carbon nanoparticles exist for a longer period on paper making the μPAD sensing route as an efficient one. This study highlights the novel use of bio-precursor based carbon nanoparticles as sensing probe and suggests their potential in future nanodevice construction.