NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARON

Multivariate calibration of UV-visible spectral data using partial least-squares (PLS) has been applied to the determination of the nitrate content in Chilean Caliche samples, in the concentration range from 1 to 20% NaNO3 The multivariate approach is required since the samples do also contain unkno...

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Autores principales:	BRAVO,MANUEL, OLWIERT,ALEJANDRO C, OELCKERS,BEATRIZ
Lenguaje:	English
Publicado:	Sociedad Chilena de Química 2009
Materias:	Nitrate determination UV-visible spectrophotometry Multivariate calibration Partial least-squares
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072009000100022
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spelling	oai:scielo:S0717-970720090001000222009-05-12NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARONBRAVO,MANUELOLWIERT,ALEJANDRO COELCKERS,BEATRIZ Nitrate determination UV-visible spectrophotometry Multivariate calibration Partial least-squares Multivariate calibration of UV-visible spectral data using partial least-squares (PLS) has been applied to the determination of the nitrate content in Chilean Caliche samples, in the concentration range from 1 to 20% NaNO3 The multivariate approach is required since the samples do also contain unknown interferences which are spectrally active in the useful wavelength region for nitrate quantitation (near 301 nm). A set of fifteen calibration samples was employed to build the multivariate model, selected using the Kennard-Stone methodology, starting from real Caliche samples whose nitrate content was previously determined using the reference Devarda method. The figures of merit of the multivariate model were satisfactory (the limit of detection and quantitation reached 0.04% and 0.12 % of NaNO3, respectively, with an average error of prediction of 0.3 % of NaNO3). Then, the PLS model was then applied to a set of independent Caliche samples. The results were compared with a univariate UV approach, and with the nitrate content determined by the reference method, using the linear regression of predicted vs. reference concentration values, together with the elliptical joint confidence region test for the slope and intercept of the latter regression. The results indícate that the univariate method is unsuitable for analyzing the presently studied samples, unlike the multivariate model. Finally, the analytical methodology proposed appears as reliable and cheap alternative for routine analysis of a large number of caliche samples.info:eu-repo/semantics/openAccessSociedad Chilena de QuímicaJournal of the Chilean Chemical Society v.54 n.1 20092009-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072009000100022en10.4067/S0717-97072009000100022
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Nitrate determination UV-visible spectrophotometry Multivariate calibration Partial least-squares
spellingShingle	Nitrate determination UV-visible spectrophotometry Multivariate calibration Partial least-squares BRAVO,MANUEL OLWIERT,ALEJANDRO C OELCKERS,BEATRIZ NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARON
description	Multivariate calibration of UV-visible spectral data using partial least-squares (PLS) has been applied to the determination of the nitrate content in Chilean Caliche samples, in the concentration range from 1 to 20% NaNO3 The multivariate approach is required since the samples do also contain unknown interferences which are spectrally active in the useful wavelength region for nitrate quantitation (near 301 nm). A set of fifteen calibration samples was employed to build the multivariate model, selected using the Kennard-Stone methodology, starting from real Caliche samples whose nitrate content was previously determined using the reference Devarda method. The figures of merit of the multivariate model were satisfactory (the limit of detection and quantitation reached 0.04% and 0.12 % of NaNO3, respectively, with an average error of prediction of 0.3 % of NaNO3). Then, the PLS model was then applied to a set of independent Caliche samples. The results were compared with a univariate UV approach, and with the nitrate content determined by the reference method, using the linear regression of predicted vs. reference concentration values, together with the elliptical joint confidence region test for the slope and intercept of the latter regression. The results indícate that the univariate method is unsuitable for analyzing the presently studied samples, unlike the multivariate model. Finally, the analytical methodology proposed appears as reliable and cheap alternative for routine analysis of a large number of caliche samples.
author	BRAVO,MANUEL OLWIERT,ALEJANDRO C OELCKERS,BEATRIZ
author_facet	BRAVO,MANUEL OLWIERT,ALEJANDRO C OELCKERS,BEATRIZ
author_sort	BRAVO,MANUEL
title	NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARON
title_short	NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARON
title_full	NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARON
title_fullStr	NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARON
title_full_unstemmed	NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARON
title_sort	nitrate determination in chilean caliche samples by uv-visible absorbance measurements and multivariate calibraron
publisher	Sociedad Chilena de Química
publishDate	2009
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072009000100022
work_keys_str_mv	AT bravomanuel nitratedeterminationinchileancalichesamplesbyuvvisibleabsorbancemeasurementsandmultivariatecalibraron AT olwiertalejandroc nitratedeterminationinchileancalichesamplesbyuvvisibleabsorbancemeasurementsandmultivariatecalibraron AT oelckersbeatriz nitratedeterminationinchileancalichesamplesbyuvvisibleabsorbancemeasurementsandmultivariatecalibraron
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NITRATE DETERMINATION IN CHILEAN CALICHE SAMPLES BY UV-VISIBLE ABSORBANCE MEASUREMENTS AND MULTIVARIATE CALIBRARON

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