title: Pyridine appended L-methionine: a novel chelating resin for pH dependent Cr speciation with scanning electron microscopic evidence and monitoring of yeast mediated green bio-reduction of Cr(VI) to Cr(III) in environmental samples.
abstract: Chemical speciation and pH dependent separation of Cr(III) and Cr(VI) species in environmental samples have been achieved by solid phase extraction using a new chelating resin containing pyridine appended L-methionine. Cr(III) is completely sorbed on the resin at pH 8.0 and Cr(VI) at pH 2.0. Hence a pH dependent separation of Cr(III) and Cr(VI) is possible with a limit of detection of 1.6 μg mL(-1) and 0.6 μg mL(-1) respectively. The sorption capacity of the resin for Cr(III) and Cr(VI) is 2.8 mmol g(-1) and 1.3 mmol g(-1) respectively. The sorption of chromium on the resin is supported by scanning electron microscopy (SEM). Complete desorption of Cr(III) and Cr(VI) from 1g of Cr loaded resin was achieved using 10 mL of 2 mol L(-1) HNO(3) and 6 mL of 3 mol L(-1) HNO(3) respectively. Quantitative recoveries of Cr(III) (pH 8.0) and Cr(VI) (pH 2.0) were found to be 96.0% and 98.0% respectively. Reduction efficiency of Rhodotornula mucilaginosa yeast from Cr(VI) to Cr(III) was monitored with this new resin. Concentrations of metal ions were measured by flame atomic absorption spectroscopy (FAAS).
authors.affiliation: Department of Chemistry, The University of Burdwan, Burdwan 713104, India.
authors.forename: Animesh
authors.initials: A
authors.lastname: Sahana
authors.forename: Sudipto
authors.initials: S
authors.lastname: Das
authors.forename: Arnab
authors.initials: A
authors.lastname: Banerjee
authors.forename: Sisir
authors.initials: S
authors.lastname: Lohar
authors.forename: Debasis
authors.initials: D
authors.lastname: Karak
authors.forename: Debasis
authors.initials: D
authors.lastname: Das
mesh_terms: D001673:Biodegradation, Environmental; D002857:Chromium / Q000145:classification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D009682:Magnetic Resonance Spectroscopy; D008715:Methionine / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013054:Spectrophotometry, Atomic; D015003:Yeasts / Q000378:metabolism*
chemical_list: D011725:Pyridines; D002857:Chromium; D008715:Methionine; C023666:pyridine