FHZ

FHZ is a highly selective, cell-permeable, non-cytotoxic, non-fluorescent 6-triethylene glycol-substituted fluorescein hydrazide that is an efficient fluorescent turn-on probe for dual channel detection of (•OH) and HOCl in live cells and zebrafish embryos. FHZ selectively reacts with hydroxyl (•OH) and HOCl, respectively, to form highly fluorescent FOBA (Ex: 410 nm & Em.: 486 nm; Φ = 0.42; ε410 = 12000/M/cm) and F-TEG (Ex: 490 nm & Em.: 520 nm; Φ = 0.34; ε490 = 7000/M/cm), while exhibiting no reactivity toward H2O2 ¹O2, O2•–, NO, or ONOO–. Cyan and green fluorescence dual-channel detection with two exciting wavelengths (405 nm and 488 nm) and two collection windows (430–490 nm; 510–560 nm) allows time-dependent quantitative detection of cellular •OH and HOCl by FHZ in live cells (50-100 μM; HeLa and RAW 264.7 macrophages) cells and zebrafish embryos (50 μM).