Journal: Geostandards and Geoanalytical Research

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2 articles found

Geochemical Fingerprinting by Handheld Laser-Induced Breakdown Spectroscopy

Author: Harmon, R. S. ; et. al.

Journal: Geostandards and Geoanalytical Research (2017)

Applications Chemometrics

DOI: 10.1111/ggr.12175

Authors
Collins, L. M. ; Hark, R. R. ; Rankey, E. C. ; Somers, A. M. ; Throckmorton, C. S. ; Wise, M. A.

Keywords

laser-induced breakdown spectroscopy; real-time chemical analysis; geochemical fingerprinting; stratigraphic correlation; provenance determination; mineral exploration;PARTIAL LEAST-SQUARES; DIAMOND EXPLORATION; GOLD MINERALIZATION; YUKON-TERRITORY; SOLID-SOLUTIONS; TRACE-ELEMENTS; RAPID ANALYSIS; ICP-MS; MINERALS; GARNET

Abstract

A broad suite of geological materials was studied a using a handheld laser-induced breakdown spectroscopy (LIBS) instrument. Because LIBS is simultaneously sensitive to all elements, the full broadband emission spectrum recorded from a single laser shot provides a chemical fingerprint' of any material - solid, liquid or gas. The distinguishing chemical characteristics of the samples analysed were identified through principal component analysis (PCA), which demonstrates how this technique for statistical analysis can be used to identify spectral differences between similar sample types based on minor and trace constituents. Partial least squares discriminant analysis (PLSDA) was used to distinguish and classify the materials, with excellent discrimination achieved for all sample types. This study illustrates through four examples (carbonate minerals and rocks, the oxide mineral pair columbite-tantalite, the silicate mineral garnet and native gold) how portable, handheld LIBS analysers can be used for real-time chemical analysis under simulated field conditions for element or mineral identification, plus such applications as stratigraphic correlation, provenance determination and natural resource exploration.

Area:

Geology

Material:

Carbonate ; Silicate

Elements:

Lines [nm]:

Ca II 315.89 nm Ca II 317.93 nm Ca II 393.37 nm Ca II 396.85 nm Ca I 442.54 nm Ca I 443.57 nm Ca I 445.48 nm Ca I 526.56 nm Ca I 527.03 nm Ca I 558.20 nm Ca I 558.88 nm Ca I 559.01 nm Ca I 559.85 nm Ca I 585.75 nm Ca I 610.27 nm Ca I 612.22 nm Ca I 616.13 nm Ca I 643.91 nm Ca I 646.26 nm Ca I 649.38 nm

Lines [nm]:

Au I 242.80 nm Au I 267.60 nm Au I 312.28 nm Au I 406.51 nm Au I 479.26 nm Au I 523.03 nm Au I 583.74 nm Au I 586.29 nm Au I 595.70 nm Au I 627.82 nm

Lines [nm]:

Mg II 279.55 nm Mg II 280.27 nm Mg I 285.21 nm Mg I 383.23 nm Mg I 383.83 nm Mg II 448.11 nm Mg I 516.73 nm Mg I 517.27 nm Mg I 518.36 nm

Lines [nm]:

Mn II 257.61 nm Mn II 259.37 nm Mn II 260.57 nm Mn I 279.48 nm Mn I 279.83 nm Mn I 403.08 nm Mn I 403.31 nm

Lines [nm]:

Ag II 241.32 nm Ag II 243.78 nm Ag I 546.55 nm Ag I 520.91 nm Ag I 328.07 nm Ag I 338.29 nm

...

Emmision lines:
Ta II 240.06 nm
Ag II 241.32 nm
Au I 242.80 nm
Ag II 243.78 nm
Mn II 257.61 nm
Mn II 259.37 nm
Mn II 260.57 nm
Au I 267.60 nm
Mn I 279.48 nm
Mg II 279.55 nm
Mn I 279.83 nm
Mg II 280.27 nm
Mg I 285.21 nm
Ta II 301.25 nm
Au I 312.28 nm
Be II 313.04 nm
Ca II 315.89 nm
Ca II 317.93 nm
Ag I 328.07 nm
Ag I 338.29 nm
Mg I 383.23 nm
Mg I 383.83 nm
Ca II 393.37 nm
Al I 394.40 nm
Al I 396.15 nm
Ca II 396.85 nm
Mn I 403.08 nm
Mn I 403.31 nm
Au I 406.51 nm
Ca I 442.54 nm
Ca I 443.57 nm
Ca I 445.48 nm
Mg II 448.11 nm
Au I 479.26 nm
Mg I 516.73 nm
Mg I 517.27 nm
Mg I 518.36 nm
Ag I 520.91 nm
Au I 523.03 nm
Ca I 526.56 nm
Ca I 527.03 nm
Ag I 546.55 nm
Ca I 558.20 nm
Ca I 558.88 nm
Ca I 559.01 nm
Ca I 559.85 nm
Au I 583.74 nm
Ca I 585.75 nm
Au I 586.29 nm
Na I 589.00 nm
Na I 589.59 nm
Au I 595.70 nm
Ca I 610.27 nm
Li I 610.35 nm
Ca I 612.22 nm
Ca I 616.13 nm
Au I 627.82 nm
Ca I 643.91 nm
Ca I 646.26 nm
Ca I 649.38 nm
H I 656.27 nm
Li I 670.78 nm

Comparison of Fused Glass Beads and Pressed Powder Pellets for the Quantitative Measurement of Al, Fe, Si and Ti in Bauxite by Laser-Induced Breakdown Spectroscopy

Author: Carvalho, A. A. C. ; et. al.

Journal: Geostandards and Geoanalytical Research (2017)

Applications

DOI: 10.1111/ggr.12173

Authors
Alves, V. C. ; Leme, F. O. ; Nomura, C. S. ; Oliveira, P. V. ; Silvestre, D. M.

Keywords

laser-induced breakdown spectroscopy; borate fusion; bauxite; sample preparation; matrix-match; pellet;PLASMA-MASS SPECTROMETRY; ELEMENTAL ANALYSES; LIBS; SAMPLES; GEOCHEMISTRY; FUSION

Abstract

Due to matrix interference and sample particle size effects, some of the most important and difficult issues in laser-induced breakdown spectroscopy (LIBS) analysis are the calibration and quantitative measurement of a complex matrix. This study proposes the use of borate fusion as an alternative sample preparation procedure for the quantitative measurement of Al, Fe, Si and Ti in bauxite by LIBS. Analytical calibration curves were made using bauxite certified reference materials (CRM), and the precision and accuracy of the methods were evaluated by analysing an additional bauxite CRM, using two different approaches: pressed powder pellets and fused glass beads. The borate fusion method was the most suitable sample preparation technique, since particle size effects and matrix interference could be minimised, obtaining better linearity on the analytical calibration curves (r(2)), and more accurate and more precise results for bauxite analysis.

Area:

Geology ; Industry

Material:

Bauxite ; Fused glass bead ; Pellet

Elements:

Lines [nm]:

Al I 394.40 nm

Emmision lines:
Al I 394.40 nm

Journal: Geostandards and Geoanalytical Research

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