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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 71(3): 751-4, 2008 Dec 01.
Article in English | MEDLINE | ID: mdl-18339578

ABSTRACT

A covellite mineral sample from Coquimbo region, Chile is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II) and Cu(II). Optical absorption spectrum indicates that Fe(II) and Cu(II) impurities are present in octahedral structure. Bands in the near-infrared from 7,000 to 5,000 cm(-1) result from the overtones of the first fundamental OH-stretching modes.


Subject(s)
Copper/chemistry , Electron Spin Resonance Spectroscopy , Iron/chemistry , Manganese/chemistry , Minerals/chemistry , Spectrophotometry , Spectrophotometry, Ultraviolet , Spectroscopy, Near-Infrared , Thermodynamics
2.
Spectrochim Acta A Mol Biomol Spectrosc ; 71(1): 31-8, 2008 Nov 01.
Article in English | MEDLINE | ID: mdl-18280774

ABSTRACT

Leaves of bhringaraj and guduchi herb of Kadapa district of Andhra Pradesh, India, are dried and powdered. ICP-MS analysis of samples indicates that copper is present in both the samples. An EPR study of guduchi sample also confirms the presence of Fe(III) whereas Eclipta alba confirms the presence of Fe(III), Mn(II) and Cu(II). Optical absorption spectrum of guduchi indicates that Cu(II) is present in rhombically distorted octahedral environment. NIR and IR results are due to carbonate fundamentals.


Subject(s)
Electron Spin Resonance Spectroscopy/methods , Iron/analysis , Mass Spectrometry/methods , Plant Extracts/analysis , Plants, Medicinal/metabolism , Spectrophotometry, Infrared/methods , Copper/analysis , Manganese/analysis , Optics and Photonics , Plant Extracts/chemistry , Spectrophotometry/methods , Spectroscopy, Near-Infrared/methods , Temperature , Trace Elements
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