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A Novel Approach to the Examination of Soil Evidence: Mineral Identification Using Infrared Microprobe Analysis *
Author(s) -
Weinger Brooke A.,
Reffner John A.,
De Forest Peter R.
Publication year - 2009
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2009.01064.x
Subject(s) - microprobe , mineral , infrared , mineralogy , absorbance , silicate minerals , chemistry , electron microprobe , infrared spectroscopy , attenuated total reflection , analytical chemistry (journal) , materials science , silicate , environmental chemistry , optics , metallurgy , chromatography , physics , organic chemistry
Identification of minerals using the infrared microprobe with a diamond internal reflection objective is a rapid and reliable method for forensic soil examinations. Ninety‐six mineral varieties were analyzed, and 77 were differentiated by their attenuated total reflection (ATR) spectra. Mineral grains may be mounted in oil for conventional polarized light microscope characterization and their ATR spectrum obtained with little or no interference by the liquid. This infrared microprobe method can be used to identify silicates, phosphates, nitrates, carbonates, and other covalent minerals; however, ionic minerals, metal oxide and sulfide minerals, and minerals with refractive indexes greater than diamond do not produce identifiable spectra, but the lack of a spectrum or one with high absorbance values does provide useful information. This research demonstrates the overall utility that infrared microprobe analysis brings mineral identification in soil evidence.