A colorimetric and fluorescence turn-on probe for the detection of ascorbic acid in living cells and beverages

Abstract

We report on a colorimetric probe based on copper-gold alloy nanoparticles (NPs). The probe is capable of selectively detecting ascorbic acid (AA) as a result of the distance-dependent colour change of the nanoparticles immobilized in an electrospun nylon-6 nanofiber. The resulting white nanofibres undergo a colour change to blue as a result of the aggregation of the NPs induced by AA in the pH range 2–7. The probe is selective for AA even in the presence of dopamine, uric acid, saccharides, amino acids and certain organic acids. It covers the 1.76 x10−2 mg L−1 to 1.76 x105 mg L−1 concentration range, and exhibits a limit of detection of 1.76 x10−2 mg L−1 based on visual detection. Its application was demonstrated by the determination of ascorbic acid in fruit juices, urine, serum, and vitamin C tablets.