Analytical chemistry
Rouhollah Heydari; Farzaneh Bastami; Mohammad Hosseini; Mohammad Alimoradi
Volume 5, Issue 3, pp. 237-363, Serial No. 16 , July 2017, , Pages 242-251
Abstract
In this study, a simple and low-cost method was developed for extraction and pre-concentration of brilliant blue(BB) and Tropaeolin O(TO) in food samples using cloud point extraction (CPE) prior to spectrophotometric determination. The effects of main factors such as pH, surfactant and salt concentrations, ...
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In this study, a simple and low-cost method was developed for extraction and pre-concentration of brilliant blue(BB) and Tropaeolin O(TO) in food samples using cloud point extraction (CPE) prior to spectrophotometric determination. The effects of main factors such as pH, surfactant and salt concentrations, incubation time and temperature on the cloud point extraction of both dyes were investigated and optimized. Linear range of calibration curves were obtained in the range of 50–4000 ng mL−1 for BB and 50–5000 ng mL−1 for TO under the optimum conditions. The limit of detection values for BB and TO were 10 and 20ng mL−1, respectively. The relative standard deviation (RSD) values of both dyes for repeated measurments (n=6) were less than 2.2 %. The obtained results demonstrate that the proposed method can be applied satisfactorily to determine these dyes in different food samples.
Analytical chemistry
Ahmadreza Amraei; Ali Niazi; Mohammad Alimoradi
Volume 5, Issue 2, pp. 121-236, Serial No. 15 , April 2017, , Pages 207-216
Abstract
Naphthol isomers were simultaneously and spectrophotometrically determined in wastewater, using a model based on net analyte signal (NAS). The calibration method used is a variation of the original hybrid linear analysis method as proposed by Goicoechea and Olivieri (HLA/GO). Owing to spectral interferences, ...
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Naphthol isomers were simultaneously and spectrophotometrically determined in wastewater, using a model based on net analyte signal (NAS). The calibration method used is a variation of the original hybrid linear analysis method as proposed by Goicoechea and Olivieri (HLA/GO). Owing to spectral interferences, the simultaneous determination of mixtures of naphthol isomers, using a spectrophotometric method, is difficult. A rapid and powerful method was used for wavelength selection in the modeling step, based on the minimization of the error indicator (EI), which was estimated as a function of the moving spectral region. The calculation of the net analytical signal using a modified HLA/GO method allows us to determine several figures of merit, as selectivity, sensitivity, analytical sensitivity and limit of detection of the proposed multivariate calibration. The limit of detection (LOD) for 1 and 2-naphthol, were 0.04 and 0.06 (µg/mL) respectively. The proposed model was tested in the analysis of wastewater samples, without previous sample preparation steps, obtaining recovery values between 98 and 104.00%, for 1-naphthol and between 97.00 and 103.00%, for 2-naphthol.