Ultra-trace level colorimetric composite sensor based on novel DH-1,6-NAPY-8-CN-AgNPs for the detection of Clonazepam in aqueous and human plasma samples

Abstract

It's crucial to develop cost-effective, rapid & reliable detection methods of specific analytes through sensors useful in the analytical and medicinal chemistry. We report a highly sensitive and selective colorimetric method for the detection of clonazepam by the new composite sensor DH-1,6-NAPY-8-CN-AgNPs containing 5-amino-7-(4-benzylpiperazin-1-yl)-2,4-bis(4-bromophenyl)-2-methyl-1,3-dihydro-1,6-naphthyridine-8-carbonitrile capped silver nanoparticles (AgNPs). The detection mechanism is based on the H-bonding interactions between clonazepam and the sensor, that caused the aggregation of NPs that initiated a sharp color change from yellow to red. The linear relationship between the adjacent absorbance values (ΔA) vs. clonazepam concentration (range = 0.05–75 µM) showed a correlation coefficient of 0.9927. The limit of detection (LOD) was 3 nM, that is very significant achievement over the existing reports. The proposed sensor is highly selective, with no interference from many other possible interfering substances. The sensor was successfully applied to the aqueous and human plasma samples, therefore DH-1,6-NAPY-8-CN-AgNPs demonstrated great potential for the on-site and real-time screening of Clonazepam.