DOI: 10.1177/0003702817697337

Authors
Han, S. H. ; Nam, S. H.

Keywords

Laser-induced breakdown spectroscopy; LIBS; multivariate analysis; soft independent modeling of class analogy; SIMCA; partial least squares discriminant analysis; PLS-DA; edible salt;INDUCED BREAKDOWN SPECTROSCOPY; SEA SALTS; LIBS; IDENTIFICATION; COMPACT; ORIGIN

Abstract

We report soft independent modeling of class analogy (SIMCA) analysis of laser-induced plasma emission spectra of edible salts from 12 different geographical origins for their classification model. The spectra were recorded by using a simple laser-induced breakdown spectroscopy (LIBS) device. Each class was modeled by principal component analysis (PCA) of the LIBS spectra. For the classification of a separate test data set, the SIMCA model showed 97% accuracy in classification. An additional insight could be obtained by comparing the SIMCA classification result with that of partial least squares discriminant analysis (PLS-DA). Different from SIMCA, the PLS-DA classification accuracy seems to be sensitive to addition of new sample classes to the whole data set. This indicates that the individual modeling approach (SIMCA) can be an alternative to global modeling (PLS-DA), particularly for the classification problems with a relatively large number of sample classes.

DOI: 10.1177/0003702817691288

Authors
Gonzalez, J. ; Chirinos, J. ; Mao, X. L. ; Oropeza, D. ; Russo, R. E. ; Yoo, J. ; Zorba, V.

Keywords

Edible salt; sulfur; laser ablation sampling; laser-induced breakdown spectroscopy; LIBS; laser ablation inductively coupled optical emission spectrometry; LA-ICP-OES; laser ablation inductively coupled plasma mass spectrometry; LA-ICP-MS;INDUCED BREAKDOWN SPECTROSCOPY; REINFORCED-CONCRETE STRUCTURES; PLASMA-MASS-SPECTROMETRY; SEA SALTS; ELEMENTS; CLASSIFICATION; INTENSITY; CHLORINE; SODIUM; ORIGIN

Abstract

We evaluated the performance of laser ablation analysis techniques such as laser-induced breakdown spectroscopy (LIBS), laser ablation inductively coupled optical emission spectrometry (LA-ICP-OES), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), in comparison with that of ICP-OES using aqueous solutions for the quantification of sulfur (S) in edible salts from different geographical origins. We found that the laser ablation based sampling techniques were not influenced by loss of S, which was observed in ICP-OES with aqueous solutions for a certain salt upon their dissolution in aqueous solutions, originating from the formation of volatile species and precipitates upon their dilution in water. Although detection of S using direct lasersampling with LA-ICP-MS has well-known isobaric and polyatomic interferences, LIBS and LA-ICP-OES showed good accuracy in the detection of S for all salts. LIBS also provided the ability to identify the dominant chemical form in which S is present in salts. Correlation between S and oxygen, oserved in LIBS spectra, provided chemical information about the presence of S2- or SO42-, which are associated with the origin and quality of edible salts.