fig3

Figure 3. Typical gas probes and their detection mechanisms. (A) Coumarin-based probe for SO₂ detection; (B) NDI-based probe for NO detection; (C) Rhodamine-based probe for H₂S detection; (D) BODIPY-based probe for CO detection; (E) Fluorescein-based probe for NO detection; (F) Methylene blue-based probe for H₂ detection; (G) Cy7-based probe for H₂S detection.