Study on the preparation of water-soluble AgInS2 quantum dots and their application in the detection of ciprofloxacin

Abstract

Water-soluble AgInS2 quantum dots (AIS QDs) were prepared by hot-injection method with thioglycolic acid (TGA) as the stabilizer. The fluorescence of as-prepared AIS QDs could be quenched effectively by ciprofloxacin. Herein, a method for the content determination of ciprofloxacin based on the fluorescence quenching effect was explored. The experimental results showed that the particle size of AIS QDs prepared at pH = 4 was about 3–8 nm, and the maximum fluorescence emission wavelength was centered at 626 nm at λex = 500 nm. The measured concentration range of ciprofloxacin could be adjusted by varying the amount of AIS QDs solution. When 0.40 mL AIS QDs solution was used for the content determination of ciprofloxacin, a good linearity relationship was achieved between the quenched efficiency of AIS QDs fluorescence and the concentration of ciprofloxacin in the range of 1.0–19.5 μg/mL, the correlation coefficient was 0.996, the detection limit of ciprofloxacin was 0.12 μg/mL, and the blank spike recoveries were in the range of 96.7–103.3%. The method is of wide detection range, excellent selectivity, high sensitivity and easy operability, could be applied for the content determination of ciprofloxacin in drugs.