pH-controlled solid-phase enrichment of Mn(II): confirmation of the structure of the extracted ternary Mn(II) complex by single crystal X-ray structure analysis

AbstractTrace-level (μg g−1) selective separation of Mn(II) from other associated metal ions have been carried out by impregnating equimolar mixture of pyridine-2, 6-dimethanol (PDM) and thiocyanate ion on silica. The sorbent showed maximum Mn(II) sorption capacity (1.23 mmol g–1) at pH 5.0. Mn(II) was completely eluted by 8.5 mL 1.0 mol L−1HNO3from 1.0 g sorbent and subsequently measured with flame atomic absorption spectrometer (FAAS).The structure of the extracted Mn(II) complex was established by Fourier transform infrared red spectra and confirmed by single crystal X-ray structure analysis. Thermogravimetric analysis (TGA) shows the stability of the isolated Mn(II) complex at the extraction temperature. Three sigma detection limit (N = 10) of the method was 0.6 μg mL−1with a relative standard deviation of 0.1% (N = 10). The method has a pre-concentration factor of 105. Marginal interference from Cu2+has been masked with NH4SCN. The developed method has been tested for trace-level separation and estimation of Mn(II) in spiked water samples.