Fluorescence Detection of p-Cresol Using a UVC LED Coupled With a CsPbBr3 Quantum Dot Film

The detection of p-Cresol is crucial for both environmental monitoring and medical diagnosis, especially as a key biomarker for evaluating the condition of patients with uremia. However, traditional liquid chromatography techniques are expensive, time-consuming, and require bulky equipment. Meanwhile, in order to overcome the limitations brought by the inner filter effect, we proposed a method to use a flip-chip (FC) UVC LED combined with a CsPbBr₃ quantum dot (QD) film as an excitation source. In this method, different concentrations of p-Cresol absorb UVC light and then emit UVB light at different intensities. Both the emitted UVB light and the directly transmitted UVC light, after interacting with p-Cresol, pass through the CsPbBr₃ QD film, which converts the UV wavelength into visible green light. The experimental results showed that the detection limit was as low as 0.639 mg/L, the linear detection range was 0.5–10 mg/L, and the correlation coefficient (R²) was 0.98715. Each detection cycle takes only 1.2 seconds to complete, greatly reducing labor intensity and enabling rapid on-site analysis.