Sensitive Detection of Hypochlorous Acid Using Porphyrin-pyridyl Conjugated Oligomer-based Fluorescent Nanoprobe
Conjugated oligomers,as analogues of conjugated polymers,allow for constructing ultrafine fluorescent nanoparticles with improved sensing sensitivity due to their more precisely defined molecular structure and smaller size.Herein,a new porphyrin-pyridyl conjugated oligomer,i.e.,Zn-TPP-OMe,was designed and synthesized via Sonogashira coupling strategy and a super-small(~2.0 nm)water-soluble fluorescent nanoprobe(Zn-TPP-OMe nanoparticles(NPs))was subsequent obtained by nanoprecipitation method.Due to the addition reaction of chlorine atom to porphyrin ring,the fluorescence intensity of Zn-TPP-OMe NPs at 619-660 nm significantly decreased with increasing HCLO concentration.Meanwhile,Zn-TPP-OMe NPs aggregated obviously after adding HClO,achieving enhanced fluorescence quenching.The fluorescence detection mechanism was verified by transmission electron microscopy(TEM),proton nuclear magnetic resonance(1H NMR)and high resolution mass spectrometry(HRMS)analyses.The experimental results indicated that the porphyrin-pyridyl conjugated oligomer nanosystem had high sensitivity(LOD=0.005 μmol/L)and excellent selectivity in detection of HClO,and was successfully applied to the sensing of HClO in actual water samples.