Determination of norfloxacin in urine and pharmaceutical samples using terbium doped zinc sulphide nanomaterials-sensitized fluorescence method.

Highly crystalline polyethylene glycol (PEG) coated Tb3+ doped ZnS nanoparticles have been synthesized and successfully used for norfloxacin sensing. The crystallographic and morphological analyses of PEG coated Tb3+ doped ZnS nanoparticles were performed by X-ray diffraction and Transmission electron microscopy, respectively. The confirmation of Tb3+ doping in ZnS host matrix was done by emission spectroscopy and energy dispersive X-ray spectroscopy. Further, the interaction of norfloxacin with PEG coated Tb3+ doped ZnS nanomaterials was confirmed by optical analysis: spectrophotometrically and spectrofluorimetrically. Norfloxacin sensing was measured by luminescence intensity which increased with increase in concentration of norfloxacin in range from 2.0 × 10-9 -8.0 × 10-7  mol L-1 , with its correlation coefficient 0.9991. The detection limit of proposed method was 0.05 × 10-9  mol L-1 . The developed luminescence method was successfully applied for the determination of norfloxacin using PEG coated Tb3+ doped ZnS nanoparticles in urine and pharmaceutical samples.