Non-parametric linear regression of discrete Fourier transform convoluted chromatographic peak responses in non-ideal conditions

Korany, Mohamed A.; Fahmy, Ossama T.; Mahgoub, Hoda; Maher, Hadir M.

doi:10.1016/j.talanta.2005.01.008

Cited by 24 publications

(20 citation statements)

References 10 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: 93%

“…[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: 93%

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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“…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: 97%

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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“…Korany et al developed a chemometric method based on non-parametric linear regression of derivative/discrete Fourier transform convoluted high performance liquid chromatographic peak responses in non-ideal conditions [19]. This technique was extended to be used in TLC response data by applying the derivative technique by itself and followed by convolution using 8-points sin x i polynomials The present study deals with applying the derivative technique by itself and followed by convolution using 8-points sin x i polynomials (discrete Fourier functions).…”

Section: Introductionmentioning

confidence: 99%

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

Korany

Hewala

Abdel-Hai

2006

Journal of Pharmaceutical and Biomedical Analysis

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Non-parametric linear regression of discrete Fourier transform convoluted chromatographic peak responses in non-ideal conditions

Cited by 24 publications

References 10 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

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

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

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