%0 Journal Article
%T Dealing with Outlier in Linear Calibration Curves: A Case Study of Graphite Furnace Atomic Absorption Spectrometry
%J -
%D 2018
%X 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 ¦Ìg L-1 and 5.18 ¦Ìg L-1, respectively. The concentrations of lead in the sample are between 2.85 ¦Ìg L-1 and 22.61¦Ìg L-1 and the uncertainty related to calibration curve vary between 1.17¦Ìg L-1 and 1.41 ¦Ìg 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 ¦Ìg L-1 and 3.96 ¦Ìg L-1, respectively. The concentration of lead in the sample vary between 2.75 ¦Ìg L-1 and 22.52 ¦Ìg 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 ¦Ìg L-1 and 1.09 ¦Ìg 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
%K Outlier
%K Calibration Curve
%K Lead
%K Graphite Furnace Atomic Absorption Spectrometry
%K Limit of Detection
%K Limit of Quantification
%K Uncertainty
%U http://www.sciencepublishinggroup.com/journal/paperinfo?journalid=206&doi=10.11648/j.wjac.20180301.12