Non-parametric linear regression of discrete Fourier transform convoluted densitometric peak responses

Korany, Mohamed A.; Hewala, Ismail I.; Abdel-Hai, Karim M.

doi:10.1016/j.jpba.2005.08.037

Cited by 17 publications

(18 citation statements)

References 20 publications

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“…[13][14][15][16][17] This was benecial in the presented non ideal cases of linearity at which the accuracy and precision of the method were recovered, as will be discussed later in the section of accuracy and precision assessment. Data at the selected points were used for the assessment of linearity, precision and accuracy.…”

Section: Methodsmentioning

confidence: 91%

“…[13][14][15][16][17] For the atomic absorbance curve of chromium at the non ideal cases of linearity, the absorbance (A) was recorded versus time at 0.1 s as time interval then the D 1 and D 2 curves were obtained using Excel soware. Application of derivative technique (D method) to GFAAS response data.…”

Section: Methodsmentioning

confidence: 99%

“…4,5 However, decreasing the slit cause a decrease in the amount of light from the resonance line itself. [13][14][15][16][17] If the calibration data points cannot be represented by a straight line, they could be t well to a curved algebraic function. An optimization of the slit width should be done to get the minimum calibration graph curvature and the least baseline noise level.…”

Section: Introductionmentioning

confidence: 99%

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Derivative-Fourier transforms-polynomial fit: a coupling of interest in common non-ideal cases arises during trace metal analysis using graphite furnace atomic absorption spectrometry

et al. 2015

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Chemometric treatment was proposed for handling graphite furnace atomic absorption (GFAAS) data. It aims at correcting the errors encountered in such a technique due to improper method parameter optimization such as: temperature of pyrolysis, absence of a chemical (matrix) modifier, slit width, concentration working range and cleaning of the graphite tube between injections. These common examples of improper method parameters optimization lead to non-ideal cases of linearity, at which the calibration curves suffer from a pronounced downward curvature. This will eventually cause a complete loss of accuracy and precision. The suggested chemometric handling of data involves the application of a derivative method to GFAA peaks followed by their convolution using 8 points sin x i polynomials (discrete Fourier functions). The calibration data points before and after the chemometric treatment were fitted using different polynomial orders to investigate the efficiency of the proposed chemometric. Also, assessment of precision and accuracy was done to test the efficiency of the method and to check the absence of polynomial over-fitting. For comparison, the analysis was done using optimized method parameters, ideal case of linearity. For the nonideal cases, t and F tests were applied to test the presence of significance differences in accuracy and precision results obtained before the data treatment and after the data treatment using different chemometric methods along with the different order polynomials used to fit the different calibration data. Fig. 1 Signal graphics of chromium metal, (a) is for the ideal case at 40 ppb conc. level and (b-e) are for the different non ideal cases at the same conc. level (40 ppb) while (f) is for the non ideal case of improper working range selection at 100 ppb conc. level. 47868 | RSC Adv., 2015, 5, 47866-47875 This journal isFig. 3 First (a) and second (b) derivative curves derived from the signal graphic in Fig. 1c (40 ppb) of the non ideal case (improper slit width selection) and their convoluted Fourier curves (a 0 ) and (b 0 ), the arrows indicates the selected points used. 47870 | RSC Adv., 2015, 5, 47866-47875 This journal is

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Section: Methodsmentioning

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Derivative-Fourier transforms-polynomial fit: a coupling of interest in common non-ideal cases arises during trace metal analysis using graphite furnace atomic absorption spectrometry

et al. 2015

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“…First, it does not assume that all the errors are in the y-direction; second, it does not assume that either the x-or y-direction errors are normally distributed; and third, it is not affected by the presence of outlying results (Korany et al 2006).…”

Section: Theil Methodsmentioning

confidence: 99%

A comparative study of some estimation methods for parameters and effects of outliers in simple regression model for research on small ruminants

Çankaya

2008

Trop Anim Health Prod

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This paper investigated estimation methods: least squares method, M-estimation, Theil method, Least Absolute Deviation method to estimate the parameters of simple regression model in situation that the underlying assumptions of least squares estimation are untenable because of outliers. To compare these methods, the effect of chest girth on body weights of German Farm x Hair crossbred kids at weaning period was examined. Chest girth of kids is independent variable and body weight at weaning period is dependent variable in the model. Mean square error and R(2) value are used to evaluate estimator performance. Because two observation values are outliers and the model estimated from this method have minimum mean square error and maximum R(2) value for different sample sizes (n = 10, 20, 30 or 50), M-estimation method is proposed to predict the parameters of the model.

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“…The application of chemometrics to the analytical signals has been widely reported using different analytical techniques, for example, spectrophotometry (Youssef and Maher, ), spectrofluorimetry (Damiani, ), polarography (Maher and Youssef, ), voltammetry (Gui et al ., ), HPLC (Korany et al ., , ), high‐performance thin layer chromatography (HPTLC) (Korany et al ., ) and gas chromatography (Tsiallou et al ., ). Moreover, chemometric methods have been significantly used in the electrophoretic analysis of drugs either for the purpose of method optimization (Garkani‐Nejad and Seyedbagheri, ; Zhu et al ., ) or for drug analysis (Erny et al ., ; Zhang et al ., ; Liu et al ., )…”

Section: Introductionmentioning

confidence: 99%

Recent advances in applications of capillary electrophoresis with Fourier transform convolution: application to kinetic study of hydrolysis of hydrochlorothiazide

Maher

2013

Biomedical Chromatography

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This manuscript discusses the application of chemometrics to the handling of capillary electrophoresis (CE) response data using the internal standard method. Derivative treatment (D method) of CE response data was used. Furthermore, convolution of the resulting derivative curves using discrete Fourier functions, the so-called D/FF method, was applied. This approach is extremely beneficial where ideal baseline separation of electrophoretic peaks cannot be achieved, as in the case of drug isomers, structural related impurities or degradation products. The potential of these methods for resolving overlapping peaks was evaluated using the hydrolysis of hydrochlorothiazide (HCT) as an illustrative model. CE analysis was performed using a deactivated fused silica capillary (55 cm effective length and 75 μm i.d.), and background electrolyte solution consisted of phosphate buffer (20 mM, pH 8.0). Both chemometric methods allowed the determination of the intact drug (HCT) and its degraded form with high a degree of accuracy and precision. This was found to be beneficial in studying the degradation kinetics of hydrolysis of HCT at different temperatures. The corresponding pseudo-first order rate constants and half-lives were calculated. Finally, the proposed method made use of diode array detection as a tool for peak identity and purity confirmation.

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Non-parametric linear regression of discrete Fourier transform convoluted densitometric peak responses

Cited by 17 publications

References 20 publications

Derivative-Fourier transforms-polynomial fit: a coupling of interest in common non-ideal cases arises during trace metal analysis using graphite furnace atomic absorption spectrometry

Derivative-Fourier transforms-polynomial fit: a coupling of interest in common non-ideal cases arises during trace metal analysis using graphite furnace atomic absorption spectrometry

A comparative study of some estimation methods for parameters and effects of outliers in simple regression model for research on small ruminants

Recent advances in applications of capillary electrophoresis with Fourier transform convolution: application to kinetic study of hydrolysis of hydrochlorothiazide

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