Sensitive and Selective Determination of Benzidine by Synthesized tragacanth-poly (Acrylic acid-co-acrylamide-GQD) Hydrogel Nanocomposite as a Highly Stable Fluorescent Probe.

Benzidine is known as a toxic and highly carcinogenic substance, so its determination is an essential issue. Until now, no effective and stable fluorescent probe based on hydrogel nanocomposite has been reported for the determination of this substance. In this work, for the first time, the synthesis and use of tragacanth-poly (acrylic acid-co-acrylamide-GQD) hydrogel nanocomposite (H-GQD) as a novel, high-stable, and selective fluorescence hydrogel nanocomposite for the identification of benzidine is reported. To achieve the maximum responsiveness of this hydrogel nanocomposite to determine benzidine, various parameters such as pH, ionic strength, hydrogel nanocomposite concentration, sensitivity, and selectivity were investigated. The results of the investigations showed that the synthesized H-GQD has excellent stability, selectivity, and linearity range of 0.3 - 12 ppm with a limit of detection of 0.098 ppm. The results of the investigation of real water samples showed that the H-GQD has excellent recovery in the range of 93.3 - 106.6%. Finally, we believe that this H-GQD as a new and highly stable fluorescent probe can be a starting point for its application in various fields and industries to identify benzidine in water samples.