Ultrasound assisted based solid phase extraction for the preconcentration and spectrophotometric determination of malachite green and methylene blue in water samples

In this study, magnetic ferrite nanoparticles CoFe2O4 were synthesized by combustion method. Magnetic solid phase extraction was carried out by ultrasonic assisted (UAMSPE) followed by UV/Vis spectrophotometer (UAMSPE-UV/Vis) to extract malachite green (MG) and methylene blue (MB) from water samples. To investigate the effects of adsorbent dosage, solution pH, ultrasonication time and volume of eluent solvent parameters on the extraction of MG and MB by CoFe2O4, the extraction experiments through the response surface methodology (RSM) were mathematically modeled and described as parameter performance. The results of extraction tests under optimal conditions showed that CoFe2O4 had a high extraction percentage. In optimal conditions, linear range of 70-550 ng mL-1 (R2 = 0.9977) and 40-450 ng mL-1 (R2 = 0.9983) were observed for MG and MB, respectively. Limit of detection (LOD) for MG and MB were 16.5 ng mL-1 and 11 ng mL-1, respectively. Relative standard deviation (RSD) was obtained in good and low values of 2.9% and 2.3% was achieved for MG and MB, respectively. The results of investigating the reusability of CoFe2O4 adsorbent showed that the adsorbent can be used for up to 5 absorption and desorption cycles. Also, the developed method was finally used successfully