Dispersive micro-solid phase extraction using magnetic multi-walled carbon nanotubes coupled with spectrofluorimetry for sensitive determination of furazolidone in biological samples

Furazolidone Antibiotics (FZD) is a feed additive for animals and poultry which is still being used illegally despite its prohibition. Therefore, development of highly sensitive, fast and reliable analytical methods for its determination at trace level is of great importance. In this study, multi-walled carbon nanotubes were oxidized and magnetized to provide a proper sorbent for the extraction and preconcentration of furazolidone from real samples. The concentrated and separated furazolidone was determined based on its quenching effect on fluorescence intensity of quantum dots. The influence of the effective parameters on this procedure such as pH, the volume of sample solution, the amount of the sorbent, type and volume of eluent and extraction time was investigated and optimized by single-variable or multivariate method of central composite design. The sorbent was characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Under the optimized conditions, for separation and preconcentration of furazolidone from 100 mL of the samples, the calibration graph was linear (R2 = 0.9987) in the range of 20-300 μg L-1 of furazolidone, with the limits of detection (LOD) and quantification (LOQ) were 9 and 18 μg L-1, respectively. The standard deviation (RSD) at the concentration level of 60 μg L-1 furazolidone (n = 6) was 2.8%. The method was successfully applied to the determination of furazolidone in poultry tissues as well as water samples