Quinoxaline based nanoprobe for selective detection of Adenine in aqueous medium: Application to Biological sample

Quinoxaline based derivative 2,3-diphenyl quinoxaline (DPQ) was synthesized followed by spectral characterization. The aqueous suspension of DPQ nanoparticles (DPQNPs) were prepared by reprecipitation method. The average particle size of NPs obtained from Dynamic Light Scattering (DLS) examination is 52 nm. While field emission scanning electron microscopy (FE-SEM) analysis of air-dried film of aqueous suspension of NPs showed spherical morphology. Aggregation Induced Enhanced Emission (AIEE) of suspension of DPQNPs found red shifted when compared with emission arising from DPQ in THF solution. The zeta potential value of NPs is -23.3 mV indicates stability and ability of DPQNPs to interact with oppositely charged analyte molecules. The recognition test based on fluorescence shows quenching of fluorescence arising from DPQNPs suspension by addition of adenine (AD) solution. Effect of interfering substances on quenching capacity of adenine examined in presence of other ions indicated that adenine response is of high order while other ions responded negligibly. The possible mechanism of fluorescence quenching of NPs upon interaction with Adenine molecule was discussed on the basis of surface adsorption and ground state complex formation between them through H-bonding. Further the proposed fluorescence quenching method was successfully applied for the detection of adenine in serum sample by standard addition method.