Non-parametric linear regression of discrete Fourier transform convoluted chromatographic peak responses under non-ideal conditions of internal standard method

Korany, Mohamed A.; Maher, Hadir M.; Galal, Shereen M.; Fahmy, Ossama T.; Ragab, Marwa A.A.

doi:10.1016/j.talanta.2010.08.046

Cited by 28 publications

(22 citation statements)

References 19 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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“…Many analytical methods have been published for the determination of SB based on spectrophotometric (Sowmya KV et al, 2011;Tang and Tan, 1998), chemometric (Korany et al, 2010;El-Gindy et al, 2005), chromatographic (Kumar et al, 2012;Zhang et al, 2011;Louchaichi et al, 2009b;Galli and Barbas, 2004), in addition to electroanalytical methods (Peres et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…Guaifenesin has been determined mainly in the presence of other drugs by spctrofluorimetric (Maher et al, 2014) spectrophotometric (Bhattacharyya et al, 2013;Pappano et al, 1997), chemometric (Korany et al, 2010;Donmez et al, 2011), chromatographic (Kolhal et al, 2014;Abdelwahab and Abdelaleem, 2013;Suneetha G et al, 2012;Younus et al, 2012;Elkady, 2010;Louhaichi et al, 2009a;Denola et al, 2009) and voltammetric (Tapsoba et al, 2005) methods.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous determination of a quaternary mixture of oxomemazine, sodium benzoate, guaifenesin and paracetamol by chromatographic methods

Farid

Ragehy

Hegazy

et al. 2014

Beni-Suef University Journal of Basic and Applied Sciences

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ParacetamolGuaifenesin Oxomemazine Sodium benzoate a b s t r a c tThe aim of the present work was to develop simple, accurate, sensitive and selective methods for the simultaneous determination of oxomemazine (Ox), sodium benzoate (SB), guaifenesin (Gu), andparacetamol (Par). Two methods were described and validated for the simultaneous determination of the four drugs in syrup and suppositories. The first method was a reversed phase HPLC and UVdetection at 220 nm. The assay was performed using C 18 column and an isocratic elution using acetonitrile e methanol e 35 mM KH2PO4 (20: 5: 75; by volume, pH was adjusted to 2.9 ± 0.1) as the mobile phase. The flow rate was 1.5 mL/ min and separation was achieved in less than 15 min. The second method was a TLCspectrodensitometric method, used to separate, identify and quantify the four drugs when present in combination. The drugs were applied on silica gel plates and development was made using methylene chloride-methanol-acetic acid-33% ammonia (89: 8.4: 2: 0.6, by volume) as a mobile phase. The bands of the four drugs were quantified by scanning spectrodensitometricaly at 270 nm. The suggested chromatographic methods were validated and applied successfully to the analysis of the syrup and suppositories.

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Least median of squares and iteratively re‐weighted least squares as robust linear regression methods for fluorimetric determination of α‐lipoic acid in capsules in ideal and non‐ideal cases of linearity

et al. 2018

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This study outlines two robust regression approaches, namely least median of squares (LMS) and iteratively re-weighted least squares (IRLS) to investigate their application in instrument analysis of nutraceuticals (that is, fluorescence quenching of merbromin reagent upon lipoic acid addition). These robust regression methods were used to calculate calibration data from the fluorescence quenching reaction (∆F and F-ratio) under ideal or non-ideal linearity conditions. For each condition, data were treated using three regression fittings: Ordinary Least Squares (OLS), LMS and IRLS. Assessment of linearity, limits of detection (LOD) and quantitation (LOQ), accuracy and precision were carefully studied for each condition. LMS and IRLS regression line fittings showed significant improvement in correlation coefficients and all regression parameters for both methods and both conditions. In the ideal linearity condition, the intercept and slope changed insignificantly, but a dramatic change was observed for the non-ideal condition and linearity intercept. Under both linearity conditions, LOD and LOQ values after the robust regression line fitting of data were lower than those obtained before data treatment. The results obtained after statistical treatment indicated that the linearity ranges for drug determination could be expanded to lower limits of quantitation by enhancing the regression equation parameters after data treatment. Analysis results for lipoic acid in capsules, using both fluorimetric methods, treated by parametric OLS and after treatment by robust LMS and IRLS were compared for both linearity conditions.

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Non-parametric linear regression of discrete Fourier transform convoluted chromatographic peak responses under non-ideal conditions of internal standard method

Cited by 28 publications

References 19 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

Simultaneous determination of a quaternary mixture of oxomemazine, sodium benzoate, guaifenesin and paracetamol by chromatographic methods

Least median of squares and iteratively re‐weighted least squares as robust linear regression methods for fluorimetric determination of α‐lipoic acid in capsules in ideal and non‐ideal cases of linearity

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