A sensitive optic fiber sensor based on CdSe QDs fluorophore for nitric oxide detection

A new fiber optic sensor was developed to detect nitric oxide (NO) in aqueous solution using CdSe quantum dots (QDs)/cellulose acetate (CA) as the sensitive membrane, in which CdSe QDs were embedded in CA via simple hybridized approach. Nitric oxide radical (NO) could react easily with dissolved oxygen in water and coordinate with Cd2+, so it was found a significant quenching effect on the fluorescence of the CdSe QDs in the sensitive membrane. The fluorescence responses were concentration-dependent and could be well described by the typical Stern–Volmer equation. NO concentrations were determined by the phase-modulation fluorometry using this new fiber optic sensor. Under optimum conditions, a linear calibration (R2 = 0.9908) was obtained in the range of 1.0 × 10−7 to 1.0 × 10−6 mol L−1 NO concentration with a detection limit of 1.0 × 10−8 mol L−1 (S/N = 3) by the modulation of optical phase delay observed.