RESUMEN
An alternative biotechnological solid phase bio-extraction (SPE) method was developed. Bacillus subtilis loaded multiwalled carbon nanotube was designed and used as biosorbent for the preconcentrations of Pb(II), Ni(II), and Zn(II). The experimental parameters such as sample flow rate, pH of sample solution, amounts of Bacillus subtilis and multiwalled carbon nanotube, volume of sample solution and reusability of column which affects the analytical characteristics of the SPE method were investigated in details. Surface structures were examined by using FTIR, SEM. The best pH was determined as 5.0 and the percentages recoveries of Zn(II), Ni(II), and Pb(II) were determined as 99.1%, 98.7%, and 96.2%, respectively, at a flow rate of 3 mL/min. In this study, in which the profitable sample volume was determined as 400 mL and the amount of multiwalled carbon nanotube (MWCNT) as 50 mg. It was also observed that the column had a significant potential to preconcentrate Zn(II), Ni(II), and Pb(II) even after 25 reuses. The biosorption capacities for Zn(II), Ni(II) and Pb(II) were calculated as 39.67 mg/g, 45.98 mg/g and 51.34 mg/g respectively. The LOD values were calculated as 0.024 ng/mL for Pb(II), 0.029 ng/mL for Ni(II), and 0.019 ng/mL for Zn(II). The linear range was detected as 0.25-25 ng/mL. The concentrations of Pb(II), Ni(II), and Zn(II) in a variety of real food samples were determined by using developed method after application of certified reference sample.
Asunto(s)
Bacillus subtilis , Nanotubos de Carbono , Nanotubos de Carbono/química , Plomo , Extracción en Fase Sólida/métodos , Concentración de Iones de Hidrógeno , ZincRESUMEN
An ecofriendly preconcentration method was developed based on the use of Geobacillus galactosidasius sp. nov immobilized on Amberlite XAD-4 as an adsorbent for the preconcentrations of Hg and Sn. SEM-EDX performed for the investigation of surface functionality and morphology. The detailed investigations of factors such as pH of the solution, flow rate, interfering ions and sample volume have been thanks to the optimization of the pre-concentration system. The optimum pHs were found as 5.0-7.0 for Hg and Sn and also the optimum flow rates were determined as 2 mL min-1 for recovery of Hg and Sn. Under the best experimental conditions, limits of detections (LOD) were found as 0.53 ng mL-1 for Hg and 0.27 ng mL-1 for Sn. RSDs were calculated as 8.2% for Hg and 6.9% for Sn. The process was validated to use certified references (fish samples). ICP-OES was used to measure the levels of Hg and Sn in various real meal patterns after the devised technique was used. Concentrations of Hg and Sn were quantitively measured on gluten-free biscuit, flour, rice, Tuna fish, meat, chicken meat, potato, chocolate, coffee, tap water, energy drink and mineral water samples with low RSD. The developed method emerges as an innovative technology that will eliminate the low cost and toxic effect.