A novel multifunctional fluorescent capillary-based sensor for simultaneous monitoring of pH, O2 and CO2

A fluorescent capillary sensor for detecting the bioanalytically and biologically relevant analytes pH, O 2 , and CO 2 has been designed. The sensor is based on single capillary tube with 2 mm inner diameter, which is simultaneous doped with emissive O 2 -sensitive indicator Ru(dpp) 3 (PF6) 2 (RuDP), pH-sensitive and CO 2 -sensitive indicator 8-hydroxypyrene-1, 3,6-trisulfonic acid trisodium salt (HPTS). The multifunctional sensor can be excited at the same wavelength and realize multi-parameter optical monitoring at the different sensing position. Studies in phosphate-buffered solutions display the excellent feasibility of the capillary sensor for fluorescence detection of pH, O 2 , and CO 2 . Overall, the multifunctional capillary sensor exhibits great potential in real-time blood gas analysis, and clinical application of multi-parameter biological detection.