Colorimetric detection of norfloxacin and ceftazidime by modified materials

Abstract

Novel approaches were developed for the colorimetric detection of norfloxacin and ceftazidime using chemically modified polymer resin and cotton sponge as sensing materials, respectively. For norfloxacin detection, the optimum condition was achieved by using a resin modified with 6.0 µM Congo red at pH 6 to extract norfloxacin in 10 mL of sample at pH 2. The reaction was completed within 15 minutes. Regarding ceftazidime detection, a cotton sponge functionalized with polyethyleneimine (PEI) was fabricated and characterized by FTIR, SEM, and ninhydrin test. To fabricate the PEI-sponge, 170 mM 3-aminopropyl triethoxysilane (APTES) was used to modify 1.0 g cotton fibers and 210 µM PEI for grafting on 0.5 g of APTES-sponges. The colorimetric detection of ceftazidime based on the azo dye formation on the sponge surface was achieved by using a reagent mixture containing 0.5 M HCl, 30 mM NaNO2, and 25 µM chromotropic acid. Under optimized conditions, the methods provide a linear range from 0 – 1.5 mg L-1 and 0.5 – 3.0 mg L-1 for norfloxacin and ceftazidime determination, respectively. The limit of detection of norfloxacin and ceftazidime was found to be 0.23 mg L-1 and 0.06 mg L-1, respectively. The methods were applied to detect norfloxacin and ceftazidime in spiked water samples with recoveries ranging from 90 – 106% and 83 – 103%, respectively, and % RSD lower than 10.53%.