SDS capped 1-pyrenecarboxaldehyde nanoprobe for selective detection of Cu 2+ ion from water sample: spectroscopic approach

The SDS capped 1-pyrenecarboxaldehyde nanoparticles (PyalNPs) prepared by reprecipitation method in aqueous medium exhibited red shifted aggregation induced enhanced emission (AIEE). The dynamic light scattering (DLS) examination showed narrower particle size distribution with average particle size 41 nm whereas -34.5 mV zeta potential value indicate the negative surface charge and good stability of nanoparticles in aqueous medium. The aggregation induced enhanced emission (AIEE) seen at λ = 473 nm in fluorescence spectrum of PyalNPs suspension. In presence of Cu ion fluorescence of PyalNPs quenches very significantly even in presence of other metal ions like Ba , Ca , Cd , Co , Al , Fe , Hg , Ni , Mg . The changes in fluorescence life time of PyalNPs in presence of Cu ion suggest the type of quenching is dynamic. The fluorescence quenching data of nanoparticles suspension fits well into typical Stern-Volmer relation in the range of concentration 1.0-25 μg/mL of Cu ion. The estimated value of correlation coefficient R = 0.9877 close to 1 shows linear relationship between quenching data and Cu ion concentration. The limit of detection (LOD) found to be 0.94 ng/mL is far below than the tolerable intake limit value 1.3 μg/mL accepted by world health organization for Cu ion in drinking water. The fluorescence quenching approach of sodium dodecyl sulfate (SDS) capped Pyal nanosuspension for copper ion quantification is of high specificity and co-existing ions found interfering very negligibly. The developed method was successfully applied for the estimation of copper ion in river water sample.