Simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs

Laser Induced Breakdown Spectroscopy (LIBS) is a versatile technique. It has enormous potential for in-situ elemental analysis of virtually any kind of material. Undesired fluctuations in analytical conditions seriously influence its quantitative measurements. Double Simultaneous Pulse (DSP) configu...

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Main Author: Rizvi, Syed Zuhaib Haider
Format: Thesis
Language:English
Published: 2015
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Online Access:http://eprints.utm.my/id/eprint/77950/1/SyedZuhaibHaiderPFS2015.pdf
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spelling my-utm-ep.779502018-07-18T07:36:53Z Simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs 2015-04 Rizvi, Syed Zuhaib Haider QC Physics Laser Induced Breakdown Spectroscopy (LIBS) is a versatile technique. It has enormous potential for in-situ elemental analysis of virtually any kind of material. Undesired fluctuations in analytical conditions seriously influence its quantitative measurements. Double Simultaneous Pulse (DSP) configuration is introduced in this work that can potentially minimize the influence of error factors and improve repeatability as well as detection limit. Its performance is compared with conventional Single Pulse (SP) LIBS configuration in a series of experiments performed under controlled environments of air and argon. Herbal samples Ficus Deltoidea, Phaleria Macrocarpa and Strobilanthes Crispus are utilized as investigative materials. Nd:YAG laser (1064 nm, 6 ns, 544 mJ) and Ocean Optics HR4000 spectrometer are employed for laser induced breakdown spectroscopic studies. Mg, Ca, Pb and Cu are quantified in samples through both configurations of LIBS. Better line profiles, emission intensities, signal-to-noise ratios (SNRs) and signal-to-background ratios (SBRs) are observed with DSP configuration. Electron density and plasma temperatures obtained from DSP configuration are slightly higher than those obtained with SP configuration. Comparatively, DSP configuration performs better in the estimation of heavy metal concentrations. Linear correlations of the calibration plots, limits of detection (LODs), relative standard deviation (RSD) and Errors of Prediction are generally improved. Minimum LODs obtained for Pb, Cu, Mg and Ca are 38.63 μg/g, 47.75 μg/g, 8.92 μg/g and 8.72 μg/g respectively. Minimum values of root mean square error of prediction (RMSEP) in the measurements, as yielded from SP and DSP configurations, are 83.13 μg/g and 43.13 μg/g respectively. Smaller errors and better repeatability are found as special traits of argon while smaller LOD is that of air environment. In this study DSP outperforms SP configuration at several fronts in both environments. It concludes that DSP can be a better alternative configuration of LIBS for quantification of heavy metals in herbal plants. 2015-04 Thesis http://eprints.utm.my/id/eprint/77950/ http://eprints.utm.my/id/eprint/77950/1/SyedZuhaibHaiderPFS2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:96675 phd doctoral Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution Universiti Teknologi Malaysia
collection UTM Institutional Repository
language English
topic QC Physics
spellingShingle QC Physics
Rizvi, Syed Zuhaib Haider
Simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs
description Laser Induced Breakdown Spectroscopy (LIBS) is a versatile technique. It has enormous potential for in-situ elemental analysis of virtually any kind of material. Undesired fluctuations in analytical conditions seriously influence its quantitative measurements. Double Simultaneous Pulse (DSP) configuration is introduced in this work that can potentially minimize the influence of error factors and improve repeatability as well as detection limit. Its performance is compared with conventional Single Pulse (SP) LIBS configuration in a series of experiments performed under controlled environments of air and argon. Herbal samples Ficus Deltoidea, Phaleria Macrocarpa and Strobilanthes Crispus are utilized as investigative materials. Nd:YAG laser (1064 nm, 6 ns, 544 mJ) and Ocean Optics HR4000 spectrometer are employed for laser induced breakdown spectroscopic studies. Mg, Ca, Pb and Cu are quantified in samples through both configurations of LIBS. Better line profiles, emission intensities, signal-to-noise ratios (SNRs) and signal-to-background ratios (SBRs) are observed with DSP configuration. Electron density and plasma temperatures obtained from DSP configuration are slightly higher than those obtained with SP configuration. Comparatively, DSP configuration performs better in the estimation of heavy metal concentrations. Linear correlations of the calibration plots, limits of detection (LODs), relative standard deviation (RSD) and Errors of Prediction are generally improved. Minimum LODs obtained for Pb, Cu, Mg and Ca are 38.63 μg/g, 47.75 μg/g, 8.92 μg/g and 8.72 μg/g respectively. Minimum values of root mean square error of prediction (RMSEP) in the measurements, as yielded from SP and DSP configurations, are 83.13 μg/g and 43.13 μg/g respectively. Smaller errors and better repeatability are found as special traits of argon while smaller LOD is that of air environment. In this study DSP outperforms SP configuration at several fronts in both environments. It concludes that DSP can be a better alternative configuration of LIBS for quantification of heavy metals in herbal plants.
format Thesis
qualification_name Doctor of Philosophy (PhD.)
qualification_level Doctorate
author Rizvi, Syed Zuhaib Haider
author_facet Rizvi, Syed Zuhaib Haider
author_sort Rizvi, Syed Zuhaib Haider
title Simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs
title_short Simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs
title_full Simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs
title_fullStr Simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs
title_full_unstemmed Simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs
title_sort simultaneous double pulse enhanced laser induced breakdown spectroscopic detection of trace heavy metals in herbs
granting_institution Universiti Teknologi Malaysia, Faculty of Science
granting_department Faculty of Science
publishDate 2015
url http://eprints.utm.my/id/eprint/77950/1/SyedZuhaibHaiderPFS2015.pdf
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