Synthesis and characterization of ZnO-nanorods loaded onto activated carbon and its application for efficient solid phase extraction and determination of BG from water samples by micro-volume spectrophotometry

The applicability of ZnO-nanorods loaded onto activated carbon (ZnO-NRs-AC) for the dispersive solid phase microextraction (DSPME) of brilliant green (BG) from water samples has been described. The ZnO-NRs-AC was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and field emission scanning electron microscopy (FE-SEM) techniques. Subsequently, the loaded BG was quantitatively eluted with N,N-dimethylformamide (DMF) and its content was determined by spectrophotometry. Various experimental parameters affected the extraction recovery including the amount of ZnO-NRs-AC, ultrasound time, pH of the sample solution and desorption conditions; these were investigated and optimized via central composite design (CCD), response surface methodology (RSM) and desirability function (DF) using STATISTICA. The optimized parameters for DSPME with ZnO-NRs-AC of BG from water samples of pH 6.0 are 5 min of sonication time, 150 mu L DMF as an eluent solvent, and an extraction procedure involving 1 mg adsorbent in 10 mL BG solution. At optimized conditions, the calibration curve was linear in the range of 10-7000 ng mL(-1) with a correlation coefficient of 0.999. The LOD (S/N = 3) and LOQ (S/N = 10) were 0.75 and 2.51 ng mL (-1), respectively. The recoveries were in the range of 93.1 to 99.3% in fish farming water and water samples with RSDs below 2.23%. Finally, water samples spiked with BG at a concentration of 500 ng mL (-1) were extracted by DSPME and analyzed by spectrophotometry. The ZnO-NRs-AC exhibited suitable properties and high adsorption capacity for the extraction of BG.