A versatile optical fiber sensor comprising an excitation-independent carbon quantum dots/cellulose acetate composite film for adrenaline detection

A novel optical sensor was constructed for the detection of adrenaline (AD) by immobilizing a carbon quantum dots (CQDs)/cellulose acetate (CA) composite film on the tip of an optical fiber via dip-coating method. The emission wavelength of the CQDs was stabled at about 520 nm when it was excited from 410 to 490 nm, showing a special excitation independent characteristic. The fluorescence intensity of the CQDs quenched by AD with high selectivity leads to development of a novel sensitive method for the AD detection. The fluorescence intensity of the optical sensor has a good linear response to the concentration of adrenaline in the range of $5~\mu \text{M}$ to $45~\mu \text{M}$ (R2 = 0.99875). This investigation illustrates that optical fiber sensor platform may have great potential for the detection of AD in biomedical fields.