Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry

Njaka Namelantsoa Andriamahenina; Elise Octavie Rasoazanany; Herinirina Nomenjanahary Ravoson; Lucienne Voahangilalao Rakotozafy; Manovantsoatsiferana Harinoely; Raoelina Andraimbololona; Randrianarivony Edmond

doi:doi:10.11648/j.wjac.20180301.12

Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry

Njaka Namelantsoa Andriamahenina, Elise Octavie Rasoazanany, Herinirina Nomenjanahary Ravoson, Lucienne Voahangilalao Rakotozafy, Manovantsoatsiferana Harinoely, Raoelina Andraimbololona, Randrianarivony Edmond

Published in World Journal of Applied Chemistry (Volume 3, Issue 1)

Received: 16 November 2017 Accepted: 24 November 2017 Published: 2 January 2018

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Abstract

Outlier in the calibration of lead by graphite furnace atomic absorption spectrometry (GF-AAS) has been studied with help of the statistical tool F-test and T-test. The process consisted on measuring five standard solutions with three replicate to prepare the calibration curve. Ordinary least squares method (OLSM) was used to get the equation of the linear calibration curve; the correlation coefficient R^² and analysis of variance (ANOVA) was used to validate the linearity of this calibration curve. Proceeding to the graphic representation and the residual plot of the calibration, a suspected outlier was found. The statistical tool F-test and T-test were used to examine the suspected outlier, they yield the same result and confirm the outlier data. The calibration curve with and without the outlier data were taken care to investigate the effect of this outlier in the limit of detection (LOD), limit of quantification (LOQ), the concentration of lead in the fourteen samples and the uncertainty related to calibration curve. It has been observed that the linearity of the calibration curve is accepted for both cases. For the case of the calibration with the outlier, the estimated LOD and LOQ were 1.76 µg L^-1 and 5.18 µg L^-1, respectively. The concentrations of lead in the sample are between 2.85 µg L^-1 and 22.61µg L^-1 and the uncertainty related to calibration curve vary between 1.17µg L^-1 and 1.41 µg L^-1. On the other hand, for the calibration without the outlier data, the value of LOD and LOQ were improved compared to the previous value, the value of these two parameters were 1.32 µg L^-1 and 3.96 µg L^-1, respectively. The concentration of lead in the sample vary between 2.75 µg L^-1 and 22.52 µg L^-1, compared to the previous concentration these value decrease from 0.40% and 3.29%. The uncertainties related to calibration curve vary between 0.90 µg L^-1 and 1.09 µg L^-1 for the second case, compared to the uncertainty in the first case, the uncertainty decreases from 22.48% to 23.53%. In conclusion, dealing with outlier improves the quality of the measurement and allow producing a reliable analytical data.

Published in	World Journal of Applied Chemistry (Volume 3, Issue 1)
DOI	10.11648/j.wjac.20180301.12
Page(s)	10-16
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2018. Published by Science Publishing Group

Keywords

Outlier, Calibration Curve, Lead, Graphite Furnace Atomic Absorption Spectrometry, Limit of Detection, Limit of Quantification, Uncertainty

References

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[2]	Vicki J Barwick, Trevor J Duguid Farrant Stephen L R Ellison, Practical Statistics for the Analytical Scientist, 2nd ed.: RSC Publishing, 2009.
[3]	Shaun Burke, "Regression and Calibration," Statistics and data analysis.
[4]	Ting Ren, Li-Jiao Zhao Wen-Si Zhong, "Determination of Pb (Lead), Cd (Cadmium), Cr(Chromium), Cu (Copper), and Ni (Nickel) in Chinesetea with high-resolution continuum source graphite furnace atomic absorption spectrometry," 2015.
[5]	Manfred Reichenba¨cher and Ju¨rgen W. Einax, Challenges in Analytical Quality Assurance, 2011.
[6]	Jacek Namie´snik Piotr Konieczka, Quality Assurance and Quality Control in the Analytical Chemical Laboratory.: WILEY-VCH, 2009.
[7]	V. Dammann, G. Donnevert W. Funk, Quality Assurance in Analytical Chemistry, 2007.
[8]	Roberto G. Junqueira Scheilla V. C. de Souza, "A procedure to assess linearity by ordinary least squares method," 2005.
[9]	Ira S. Krull Michael E. Swartz, Handbook of Analytical Validation, 2012.
[10]	RAZAFINTSALAMA Volasoa Tahiana, Dosage de métaux lourds (Pb, Cd, Fe) par la spectrométrie d’absorption atomique dans les tissus animaux, 2009.
[11]	Ypatia Zannikou, Fanourios Zannikos Dimitrios Theodorou, "Estimation of the standard uncertainty of a calibration curve: application to sulfur mass concentration determination in fuels," 2011.
[12]	Geneva International Organization for Standardization,.
[13]	A Williams S L R Ellison, Quantifying Uncertainty in Analytical Measurement. CG, EURACHEM / CITAC Guide, 2012.
[14]	Md Pauzi Abdullah, Zuriati Zakaria, Seyedeh Belin Tavakoli Sany, Majid Rezayi, Houshang Hassonizadeh Naghmeh Saadati, "Limit of detection and limit of quantification development procedures for organochlorine pesticides analysis in water and sediment matrices," in Chemistry Central Journal., 2013.

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Njaka Namelantsoa Andriamahenina, Elise Octavie Rasoazanany, Herinirina Nomenjanahary Ravoson, Lucienne Voahangilalao Rakotozafy, Manovantsoatsiferana Harinoely, et al. (2018). Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry. World Journal of Applied Chemistry, 3(1), 10-16. https://doi.org/10.11648/j.wjac.20180301.12

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Njaka Namelantsoa Andriamahenina; Elise Octavie Rasoazanany; Herinirina Nomenjanahary Ravoson; Lucienne Voahangilalao Rakotozafy; Manovantsoatsiferana Harinoely, et al. Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry. World J. Appl. Chem. 2018, 3(1), 10-16. doi: 10.11648/j.wjac.20180301.12

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Njaka Namelantsoa Andriamahenina, Elise Octavie Rasoazanany, Herinirina Nomenjanahary Ravoson, Lucienne Voahangilalao Rakotozafy, Manovantsoatsiferana Harinoely, et al. Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry. World J Appl Chem. 2018;3(1):10-16. doi: 10.11648/j.wjac.20180301.12

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@article{10.11648/j.wjac.20180301.12,
  author = {Njaka Namelantsoa Andriamahenina and Elise Octavie Rasoazanany and Herinirina Nomenjanahary Ravoson and Lucienne Voahangilalao Rakotozafy and Manovantsoatsiferana Harinoely and Raoelina Andraimbololona and Randrianarivony Edmond},
  title = {Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry},
  journal = {World Journal of Applied Chemistry},
  volume = {3},
  number = {1},
  pages = {10-16},
  doi = {10.11648/j.wjac.20180301.12},
  url = {https://doi.org/10.11648/j.wjac.20180301.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.wjac.20180301.12},
  abstract = {Outlier in the calibration of lead by graphite furnace atomic absorption spectrometry (GF-AAS) has been studied with help of the statistical tool F-test and T-test. The process consisted on measuring five standard solutions with three replicate to prepare the calibration curve. Ordinary least squares method (OLSM) was used to get the equation of the linear calibration curve; the correlation coefficient R² and analysis of variance (ANOVA) was used to validate the linearity of this calibration curve. Proceeding to the graphic representation and the residual plot of the calibration, a suspected outlier was found. The statistical tool F-test and T-test were used to examine the suspected outlier, they yield the same result and confirm the outlier data. The calibration curve with and without the outlier data were taken care to investigate the effect of this outlier in the limit of detection (LOD), limit of quantification (LOQ), the concentration of lead in the fourteen samples and the uncertainty related to calibration curve. It has been observed that the linearity of the calibration curve is accepted for both cases. For the case of the calibration with the outlier, the estimated LOD and LOQ were 1.76 µg L-1 and 5.18 µg L-1, respectively. The concentrations of lead in the sample are between 2.85 µg L-1 and 22.61µg L-1 and the uncertainty related to calibration curve vary between 1.17µg L-1 and 1.41 µg L-1. On the other hand, for the calibration without the outlier data, the value of LOD and LOQ were improved compared to the previous value, the value of these two parameters were 1.32 µg L-1 and 3.96 µg L-1, respectively. The concentration of lead in the sample vary between 2.75 µg L-1 and 22.52 µg L-1, compared to the previous concentration these value decrease from 0.40% and 3.29%. The uncertainties related to calibration curve vary between 0.90 µg L-1 and 1.09 µg L-1 for the second case, compared to the uncertainty in the first case, the uncertainty decreases from 22.48% to 23.53%. In conclusion, dealing with outlier improves the quality of the measurement and allow producing a reliable analytical data.},
 year = {2018}
}

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TY  - JOUR
T1  - Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry
AU  - Njaka Namelantsoa Andriamahenina
AU  - Elise Octavie Rasoazanany
AU  - Herinirina Nomenjanahary Ravoson
AU  - Lucienne Voahangilalao Rakotozafy
AU  - Manovantsoatsiferana Harinoely
AU  - Raoelina Andraimbololona
AU  - Randrianarivony Edmond
Y1  - 2018/01/02
PY  - 2018
N1  - https://doi.org/10.11648/j.wjac.20180301.12
DO  - 10.11648/j.wjac.20180301.12
T2  - World Journal of Applied Chemistry
JF  - World Journal of Applied Chemistry
JO  - World Journal of Applied Chemistry
SP  - 10
EP  - 16
PB  - Science Publishing Group
SN  - 2637-5982
UR  - https://doi.org/10.11648/j.wjac.20180301.12
AB  - Outlier in the calibration of lead by graphite furnace atomic absorption spectrometry (GF-AAS) has been studied with help of the statistical tool F-test and T-test. The process consisted on measuring five standard solutions with three replicate to prepare the calibration curve. Ordinary least squares method (OLSM) was used to get the equation of the linear calibration curve; the correlation coefficient R² and analysis of variance (ANOVA) was used to validate the linearity of this calibration curve. Proceeding to the graphic representation and the residual plot of the calibration, a suspected outlier was found. The statistical tool F-test and T-test were used to examine the suspected outlier, they yield the same result and confirm the outlier data. The calibration curve with and without the outlier data were taken care to investigate the effect of this outlier in the limit of detection (LOD), limit of quantification (LOQ), the concentration of lead in the fourteen samples and the uncertainty related to calibration curve. It has been observed that the linearity of the calibration curve is accepted for both cases. For the case of the calibration with the outlier, the estimated LOD and LOQ were 1.76 µg L-1 and 5.18 µg L-1, respectively. The concentrations of lead in the sample are between 2.85 µg L-1 and 22.61µg L-1 and the uncertainty related to calibration curve vary between 1.17µg L-1 and 1.41 µg L-1. On the other hand, for the calibration without the outlier data, the value of LOD and LOQ were improved compared to the previous value, the value of these two parameters were 1.32 µg L-1 and 3.96 µg L-1, respectively. The concentration of lead in the sample vary between 2.75 µg L-1 and 22.52 µg L-1, compared to the previous concentration these value decrease from 0.40% and 3.29%. The uncertainties related to calibration curve vary between 0.90 µg L-1 and 1.09 µg L-1 for the second case, compared to the uncertainty in the first case, the uncertainty decreases from 22.48% to 23.53%. In conclusion, dealing with outlier improves the quality of the measurement and allow producing a reliable analytical data.
VL  - 3
IS  - 1
ER  -

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Author Information

Njaka Namelantsoa Andriamahenina

Department of X-Ray Fluorescence and Environment, Institut National des Sciences et Techniques Nucléaires, Antananarivo, Madagascar
Elise Octavie Rasoazanany

Department of X-Ray Fluorescence and Environment, Institut National des Sciences et Techniques Nucléaires, Antananarivo, Madagascar
Herinirina Nomenjanahary Ravoson

Department of X-Ray Fluorescence and Environment, Institut National des Sciences et Techniques Nucléaires, Antananarivo, Madagascar
Lucienne Voahangilalao Rakotozafy

Department of X-Ray Fluorescence and Environment, Institut National des Sciences et Techniques Nucléaires, Antananarivo, Madagascar
Manovantsoatsiferana Harinoely

Department of X-Ray Fluorescence and Environment, Institut National des Sciences et Techniques Nucléaires, Antananarivo, Madagascar
Raoelina Andraimbololona

Department of Theoretical Physics, Institut National des Sciences et Techniques Nucléaires, Antananarivo, Madagascar
Randrianarivony Edmond

Department of Physics, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar

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APA Style

Njaka Namelantsoa Andriamahenina, Elise Octavie Rasoazanany, Herinirina Nomenjanahary Ravoson, Lucienne Voahangilalao Rakotozafy, Manovantsoatsiferana Harinoely, et al. (2018). Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry. World Journal of Applied Chemistry, 3(1), 10-16. https://doi.org/10.11648/j.wjac.20180301.12

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ACS Style

Njaka Namelantsoa Andriamahenina; Elise Octavie Rasoazanany; Herinirina Nomenjanahary Ravoson; Lucienne Voahangilalao Rakotozafy; Manovantsoatsiferana Harinoely, et al. Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry. World J. Appl. Chem. 2018, 3(1), 10-16. doi: 10.11648/j.wjac.20180301.12

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AMA Style

Njaka Namelantsoa Andriamahenina, Elise Octavie Rasoazanany, Herinirina Nomenjanahary Ravoson, Lucienne Voahangilalao Rakotozafy, Manovantsoatsiferana Harinoely, et al. Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry. World J Appl Chem. 2018;3(1):10-16. doi: 10.11648/j.wjac.20180301.12

Copy | Download

@article{10.11648/j.wjac.20180301.12,
  author = {Njaka Namelantsoa Andriamahenina and Elise Octavie Rasoazanany and Herinirina Nomenjanahary Ravoson and Lucienne Voahangilalao Rakotozafy and Manovantsoatsiferana Harinoely and Raoelina Andraimbololona and Randrianarivony Edmond},
  title = {Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry},
  journal = {World Journal of Applied Chemistry},
  volume = {3},
  number = {1},
  pages = {10-16},
  doi = {10.11648/j.wjac.20180301.12},
  url = {https://doi.org/10.11648/j.wjac.20180301.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.wjac.20180301.12},
  abstract = {Outlier in the calibration of lead by graphite furnace atomic absorption spectrometry (GF-AAS) has been studied with help of the statistical tool F-test and T-test. The process consisted on measuring five standard solutions with three replicate to prepare the calibration curve. Ordinary least squares method (OLSM) was used to get the equation of the linear calibration curve; the correlation coefficient R² and analysis of variance (ANOVA) was used to validate the linearity of this calibration curve. Proceeding to the graphic representation and the residual plot of the calibration, a suspected outlier was found. The statistical tool F-test and T-test were used to examine the suspected outlier, they yield the same result and confirm the outlier data. The calibration curve with and without the outlier data were taken care to investigate the effect of this outlier in the limit of detection (LOD), limit of quantification (LOQ), the concentration of lead in the fourteen samples and the uncertainty related to calibration curve. It has been observed that the linearity of the calibration curve is accepted for both cases. For the case of the calibration with the outlier, the estimated LOD and LOQ were 1.76 µg L-1 and 5.18 µg L-1, respectively. The concentrations of lead in the sample are between 2.85 µg L-1 and 22.61µg L-1 and the uncertainty related to calibration curve vary between 1.17µg L-1 and 1.41 µg L-1. On the other hand, for the calibration without the outlier data, the value of LOD and LOQ were improved compared to the previous value, the value of these two parameters were 1.32 µg L-1 and 3.96 µg L-1, respectively. The concentration of lead in the sample vary between 2.75 µg L-1 and 22.52 µg L-1, compared to the previous concentration these value decrease from 0.40% and 3.29%. The uncertainties related to calibration curve vary between 0.90 µg L-1 and 1.09 µg L-1 for the second case, compared to the uncertainty in the first case, the uncertainty decreases from 22.48% to 23.53%. In conclusion, dealing with outlier improves the quality of the measurement and allow producing a reliable analytical data.},
 year = {2018}
}

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TY  - JOUR
T1  - Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry
AU  - Njaka Namelantsoa Andriamahenina
AU  - Elise Octavie Rasoazanany
AU  - Herinirina Nomenjanahary Ravoson
AU  - Lucienne Voahangilalao Rakotozafy
AU  - Manovantsoatsiferana Harinoely
AU  - Raoelina Andraimbololona
AU  - Randrianarivony Edmond
Y1  - 2018/01/02
PY  - 2018
N1  - https://doi.org/10.11648/j.wjac.20180301.12
DO  - 10.11648/j.wjac.20180301.12
T2  - World Journal of Applied Chemistry
JF  - World Journal of Applied Chemistry
JO  - World Journal of Applied Chemistry
SP  - 10
EP  - 16
PB  - Science Publishing Group
SN  - 2637-5982
UR  - https://doi.org/10.11648/j.wjac.20180301.12
AB  - Outlier in the calibration of lead by graphite furnace atomic absorption spectrometry (GF-AAS) has been studied with help of the statistical tool F-test and T-test. The process consisted on measuring five standard solutions with three replicate to prepare the calibration curve. Ordinary least squares method (OLSM) was used to get the equation of the linear calibration curve; the correlation coefficient R² and analysis of variance (ANOVA) was used to validate the linearity of this calibration curve. Proceeding to the graphic representation and the residual plot of the calibration, a suspected outlier was found. The statistical tool F-test and T-test were used to examine the suspected outlier, they yield the same result and confirm the outlier data. The calibration curve with and without the outlier data were taken care to investigate the effect of this outlier in the limit of detection (LOD), limit of quantification (LOQ), the concentration of lead in the fourteen samples and the uncertainty related to calibration curve. It has been observed that the linearity of the calibration curve is accepted for both cases. For the case of the calibration with the outlier, the estimated LOD and LOQ were 1.76 µg L-1 and 5.18 µg L-1, respectively. The concentrations of lead in the sample are between 2.85 µg L-1 and 22.61µg L-1 and the uncertainty related to calibration curve vary between 1.17µg L-1 and 1.41 µg L-1. On the other hand, for the calibration without the outlier data, the value of LOD and LOQ were improved compared to the previous value, the value of these two parameters were 1.32 µg L-1 and 3.96 µg L-1, respectively. The concentration of lead in the sample vary between 2.75 µg L-1 and 22.52 µg L-1, compared to the previous concentration these value decrease from 0.40% and 3.29%. The uncertainties related to calibration curve vary between 0.90 µg L-1 and 1.09 µg L-1 for the second case, compared to the uncertainty in the first case, the uncertainty decreases from 22.48% to 23.53%. In conclusion, dealing with outlier improves the quality of the measurement and allow producing a reliable analytical data.
VL  - 3
IS  - 1
ER  -

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