Ultrasound assisted-dispersive-micro-solid phase extraction based on bulky amino bimodal mesoporous silica nanoparticles for speciation of trace manganese (II)/(VII) ions in water samples

This report described the use of amine-functionalized mesoporous silica UVM-7 as nanoadsorbent in ultrasound assisted-dispersive-micro-solid phase extraction (US-D-μ-SPE) procedure for rapid speciation/preconcentration of trace amounts of manganese (II) and manganese (VII) ions, from water samples prior to their determination by atom trapping-flame atomic absorption spectrometry (AT-F AAS). All main factors for the quantitative recoveries of Mn(II)/Mn(VII) ions were investigated and optimized. Based on the developed method, preconcentration and speciation of Mn(II) and Mn(VII) ions with NH2-UVM-7 were obtained in water samples due to the formation of -NH-Mn2 + and -NH3+-MnO4− at optimum pH of 8 and 5, respectively. The batch adsorption capacity of NH2-UVM-7 for Mn(II) and Mn(VII) ions was found to be 1733 μmol g− 1 and 570 μmol g− 1, respectively. Under the optimized conditions, limits of detection (3Sb/m), and limits of quantification (10Sb/m) were 0.007 μg L− 1 and 0.03 μg L− 1 for Mn(II) as well as 0.008 μg L− 1 and 0.04 μg L− 1 for Mn(VII). The preconcentration factors for Mn(II) and Mn(VII) were calculated as 102.3 and 98.8, and their relative standard deviations were 2.3 and 2.8%, respectively (n = 10, C = 10 μg L− 1). The developed method was successfully applied to natural water samples. The validation of the method was also performed by the standard reference material.