Synthesis and characterization of bromophenol blue encapsulated silica and silica-titania nanocomposites for detection of volatile organic vapors

Owing to pH sensing applications in the food industry, bromophenol blue immobilized silica (BPB-S) and silicatitania (BPB-ST) nanocomposites are synthesized by the sol-gel route. Fundamental analysis confirms that both nanomatrices have porous surface and thermal stability at >= 400 C. Evanescent wave absorption-based fiber optic pH sensors are prepared by coating of BPB-S and BPB-ST nanocomposites. when the evanescent field interacts with the sensing coating, absorption varied due to pH change and the output intensity is recorded as a sensor response. The sensitivity of the BPB-S and BPB-ST nanocomposite is calculated as -136.65 counts/pH and - 17.95 counts/pH, respectively. The BPB-ST nano-matrix exhibited a fast response 0.2 s than BPB-S nanocomposite response 0.8 s. The fish's freshness is determined visually by assessing the change in the color against the fish pH. The findings confirm that synthesized nanocomposites have the potential to detect volatile organic vapors in terms of pH.

Automated summary

Silica-based bromophenol blue immobilized materials (BPB-S and BPB-ST) were synthesized for pH sensing applications in the food industry. The nanocomposites exhibit porous surfaces and thermal stability, with BPB-ST showing faster response time compared to BPB-S. These materials have potential for detecting volatile organic vapors and assessing freshness visually based on fish pH changes.