Dispersive micro-solid phase extraction using magnetic nanoparticle modified multi-walled carbon nanotubes coupled with surfactant-enhanced spectrofluorimetry for sensitive determination of lomefloxacin and ofloxacin from biological samples

A dispersive micro-solid-phase extraction (D-μ-SPE) procedure coupled with surfactant-enhanced spectrofluorimetric detection was developed for determination of ofloxacin and lomefloxacin from biological and environmental samples. The D-μ-SPE procedure was performed using magnetic Fe3O4 nanoparticle grafted multi-walled carbon nanotube as an efficient adsorbent. The main factors affecting the signal enhancement (including surfactant concentration and pH) and extraction efficiency (including pH, extraction time, sample volume, amount of magnetic adsorbent, and desorption conditions) were investigated in detail. Under the optimized conditions, the calibration curves were linear (R2˃0.9995) over the concentration range of 50–450ngmL−1 with detection limits (LOD) of 12 and 15ngmL−1 for ofloxacin and lomefloxacin respectively. The relative standard deviation (RSD %) of 1.9 and 2.1% (C=100ngmL−1, n=5) and the enrichment factor of 192 and 188 were achieved for ofloxacin and lomefloxacin respectively. Finally, the method was successfully applied to the extraction and preconcentration of these drugs in biological (plasma and urine) samples. [Display omitted] •Dispersive micro-solid phase extraction of ofloxacin and lomefloxacin using magnetic multi-walled carbon nanotubes was proposed.•Sensitive surfactant-enhanced spectrofluorimetric detection based on SDS micelles was performed after D-μ-SPE.•Factors affecting the signal enhancement and extraction efficiency of the drugs were investigated in detail.•Method was applied for determination of ofloxacin and lomefloxacin in human plasma, urine, tap and surface water samples.