scholarly journals Simultaneous Determination of Cu(II) and Ag(I) on SP Sephadex C25 as Complexes with 1-Phenyl-1,2-Propanedione-2-Oximethiosemicarbazone by Derivative Spectrophotometry

2007 ◽  
Vol 90 (6) ◽  
pp. 1695-1700 ◽  
Author(s):  
Libby Morales ◽  
M Inés Toral
Keyword(s):  
Simultaneous Determination ◽  
Inductively Coupled Plasma ◽  
Solid Phase ◽  
Industrial Effluents ◽  
Derivative Spectrophotometry ◽  
Zero Crossing ◽  
Inductively Coupled ◽  
Relative Standard ◽  
Stirring Time

Abstract The proposed method was based on retention and preconcentration of the complexes Cu(II)PPDOT and Ag(I)PPDOT on a solid phase in acid medium. The complexes were quantitatively retained in the cation exchanger SP Sephadex C25, and the analytical measurements were executed directly in the solid phase by derivative spectrophotometry. In this simultaneous determination, the second derivative and the zero crossing method were used. The determination of copper and silver was carried out to 321.0 and 427.0 nm, respectively. In order to obtain quantitative recoveries of the metal ions, various experimental analytical parameters, such as pH, stirring time, volume, and amount of solid phase, were optimized. The effect of interfering ions on the determination was described. The recovery values for Cu(II) and Ag(I) were found to be >98, and the relative standard deviation was 2. The detection limits (3 criterion) for Cu(II) and Ag(I) were found to be 0.9 108 and 13 108 M, respectively. The developed method was utilized for preconcentration and determination of Cu(II) and Ag(I) in industrial effluents and natural water samples. The results were consistent with those provided by inductively coupled plasma/mass spectrometry.

scholarly journals Application of Derivative Spectrophotometry for Simultaneous Determination of Quinapril and Hydrochlorothiazide in the Combination Tablets

2004 ◽  
Vol 87 (4) ◽  
pp. 847-851 ◽  
Author(s):  
Dorota Kowalczuk ◽  
Hanna Hopkała
Keyword(s):  
Standard Deviation ◽  
Simultaneous Determination ◽  
Relative Standard Deviation ◽  
Spectrophotometric Method ◽  
Derivative Spectrophotometry ◽  
Order Derivative ◽  
Zero Crossing ◽  
Relative Standard ◽  
Separation Of Components

Abstract A new second-order-derivative spectrophotometric method using zero-crossing technique measures quinapril (QUI) and hydrochlorothiazide (HYD) in 2-component mixtures. The procedure does not require prior separation of components from the sample. QUI was determined at a wavelength of 211.6 nm (zero-crossing wavelength point of HYD). Similarly, HYD was measured at 270.8 nm (zero-crossing wavelength point of QUI). Calibration graphs were constructed over the concentration range of 4.0 to 24.0 μ/mL for QUI and 2.5 to 15.0 μg/mL for HYD. Detection and quantitation limits were 0.85 and 2.5 μg/mL for QUI and 0.12 and 0.4 μg/mL for HYD, respectively. The accuracy (recovery 100.5–102%), precision (relative standard deviation less than 3.5% for QUI and 1.5% for HYD), selectivity, and sensitivity of the elaborated methods were satisfactory. The proposed method was applied successfully for the determination of both drugs in QUI-HYD tablets.

scholarly journals Simultaneous Determination of Estradiol and Medroxyprogesterone Acetate in Pharmaceutical Formulations by Second-Derivative Spectrophotometry

2002 ◽  
Vol 85 (4) ◽  
pp. 883-888 ◽  
Author(s):  
M Inés Toral ◽  
César Soto ◽  
Pablo Richter ◽  
Ana E Tapai
Keyword(s):  
Simultaneous Determination ◽  
Medroxyprogesterone Acetate ◽  
Signal To Noise Ratio ◽  
Pharmaceutical Formulations ◽  
Derivative Spectrophotometry ◽  
Fast Method ◽  
Second Derivative ◽  
Zero Crossing ◽  
Relative Standard

Abstract This paper reports a simple and fast method for the simultaneous determination of estradiol (ED) and medroxyprogesterone acetate (MP) in pharmaceutical formulations by second-derivative spectrophotometry. Methanol was used to extract the drugs from formulations, and subsequently the extracts were evaluated directly by derivative spectrophotometry. The drugs were determined simultaneously by using the graphic method at 297.4 nm for ED and the zero-crossing method at 273.4 nm for MP. If both compounds are present together in a sample, it is possible to quantitate one in the presence of the other. The best signal-to-noise ratio was found when the second derivative of the spectrum was used. The linear ranges for determination of the drugs were 4.7 × 10−6 to 1.6 × 10−4 and 7.2 × 10−6 to 2.0 × 10−4 mol/L for ED and MP, respectively. The ingredients commonly found in commercial pharmaceutical formulations do not interfere with the determination. Chemical and spectral variables were optimized for the determination of both analytes. Good levels of repeatability (relative standard deviation), 1.4 and 1.9%, were obtained for ED and MP, respectively. The proposed method was applied to the determination of these drugs in pharmaceutical formulations.

Simultaneous Determination of Ruthenium and Zinc in Catalysts for Hydrogenation of Benzene to Cyclohexene Using Sodium Peroxide Fusion Sample Digestion and ICP-OES

2014 ◽  
Vol 1004-1005 ◽  
pp. 1281-1284
Author(s):  
Xiao Juan Wei ◽  
Zhi Quan Tian
Keyword(s):  
Simultaneous Determination ◽  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Sample Digestion ◽  
Inductively Coupled ◽  
Relative Standard ◽  
Plasma Optical Emission Spectrometry ◽  
Novel Method

A novel method for simultaneous determination of ruthenium and zinc in catalysts for hydrogenation of benzene to cyclohexene was established by inductively coupled plasma optical emission spectrometry after sample digestion by high temperature fusion with Na2O2. Such experiment conditions were investigated as the influence of sample digestion methods, fusion time, fusion temperature, the dosage of Na2O2and interfering ions on the determination. Under the optimized conditions, the limits of detection (LODs) of Ru and Zn for tested solutions were 11 and 13 ng mL-1, respectively. The relative standard deviations (RSDs) for Ru and Zn were 2.01 and 2.35 % (CRu, Zn= 1 mg L-1, n = 7), respectively. The linear ranges of calibration graphs for Ru and Zn were 0.05 ~ 100.00 mg L-1and 0.04 ~ 50.00 mg L-1, respectively. The proposed method was applied to determine catalyst samples with good recoveries and satisfactory results.

scholarly journals Solid phase extraction and determination of indium using multiwalled carbon nanotubes modified with magnetic nanoparticles

2018 ◽  
Vol 1 (01) ◽  
pp. 5-10 ◽  
Author(s):  
Ehsan Zolfonoun
Keyword(s):  
Inductively Coupled Plasma ◽  
Solid Phase ◽  
Optical Emission ◽  
Environmental Water ◽  
Sample Volume ◽  
Emission Spectrometry ◽  
Multiwalled Carbon ◽  
Inductively Coupled ◽  
Relative Standard

In this work MWCNTs-Fe3O4 nanocomposite was used as an adsorbent for extraction and preconcentration of indium from aqueous solutions. The magnetic MWCNTs with adsorbed analytes were easily separated from the aqueous solution by applying an external magnetic field. After elution of the adsorbed analytes, the concentration of indium was determined using inductively coupled plasma optical emission spectrometry determination. The effects of pH, sorbent amount, eluent type, chelating reagent concentration, sample volume and time on the recovery of the In(III) were investigated. Under the optimum conditions, the detection limit for In(III) was 0.28 μg L−1. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of ten replicates, was 3.1 %. The method was successfully applied for the determination of In(III) in environmental water samples.

scholarly journals Simultaneous Determination of N-Butylscopolamine and Oxazepam in Pharmaceutical Formulations by First-Order Digital Derivative Spectrophotometry

2005 ◽  
Vol 88 (4) ◽  
pp. 1173-1178 ◽  
Author(s):  
Maria Inés Toral ◽  
Marcelo A Muñoz ◽  
Sandra L Orellana
Keyword(s):  
Standard Deviation ◽  
Simultaneous Determination ◽  
Relative Standard Deviation ◽  
Pharmaceutical Formulations ◽  
Derivative Spectrophotometry ◽  
Simple Method ◽  
Zero Crossing ◽  
First Order ◽  
Relative Standard

Abstract A simple method has been developed for the simultaneous determination of N-butylscopolamine bromide and oxazepam in pharmaceutical formulations using first-order digital derivative spectrophotometry. Acetonitrile was selected as the solvent in which both compounds showed well-defined bands. Both analytes showed good stability in this solvent when solutions of the analytes were exposed to light and temperatures between 20° and 80°C. The simultaneous determination of both drugs was performed by the zero-crossing method at 226.0 and 257.0 nm for N-butylscopolamine and oxazepam, respectively. The linear range of determination was found to be 2.5 × 10−7 to 8.0 × 10−5 mol/L for N-butylscopolamine and 7.1 × 10−8 to 8.0 × 10−5 mol/L for oxazepam. A very good level of repeatability (relative standard deviation) of 0.2% was observed for N-butylscopolamine and oxazepam. The ingredients commonly found in pharmaceutical formulations do not interfere. The proposed method was applied to the determination of these drugs in pharmaceutical formulations (capsules).

Simultaneous Determination of Ruthenium, Zinc and Zirconium in Waste Zirconium Dioxide Loaded Ruthenium-Zinc Catalysts Using Inductively Coupled Plasma Optical Emission Spectrometry

2014 ◽  
Vol 989-994 ◽  
pp. 480-483
Author(s):  
Xiao Juan Wei ◽  
Jian Ming Pan
Keyword(s):  
Simultaneous Determination ◽  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Sample Digestion ◽  
Inductively Coupled ◽  
Relative Standard ◽  
Plasma Optical Emission Spectrometry ◽  
Optimized Conditions

A technique for simultaneous determination of Ru, Zn and Zr in waste Ru-Zn/ZrO2catalysts using ICP-OES after sample digestion by high temperature fusion with KOH-KNO3mixture was described. Such experiment conditions were investigated as the influence of sample digestion methods, fusion time, fusion temperature, the dosage of KOH-KNO3mixture and interfering ions on the determination. Under the optimized conditions, the limits of detection (LODs) of Ru, Zn and Zr for tested solutions were 11, 8 and 5 ng mL-1, respectively. The relative standard deviations (RSDs) for Ru, Zn and Zr were 2.01, 2.55 and 1.92 % (CRu, Zn,Zr= 1 mg L-1, n = 7), respectively. The linear ranges of calibration graphs for Ru, Zn and Zr were 0 ~ 100.00 mg L-1, 0 ~ 50.00 mg L-1and 0~60.00 mg L-1, respectively. The proposed method was applied to determine the practical samples with good recoveries and satisfactory results.

scholarly journals Three Different Spectrophotometric Methods for Simultaneous Determination of Pyriproxyfen and Chlorothalonil Residues in Cucumber and Cabbage Samples

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Shilan A. Omer ◽  
Nabil A. Fakhre
Keyword(s):  
Simultaneous Determination ◽  
Simultaneous Estimation ◽  
Zero Crossing ◽  
Spectrophotometric Methods ◽  
First Derivative ◽  
The Third ◽  
Mean Centering ◽  
Relative Standard ◽  
One Way Anova

In this study, three simple and accurate spectrophotometric methods for simultaneous determination of pyriproxyfen and chlorothalonil residues in cucumbers and cabbages grown in experimental greenhouse were studied. The first method was based on the zero-crossing technique measurement for first and second derivative spectrophotometry. The second method was based on the first derivative of the ratio spectra. However, the third method was based on mean centering of ratio spectra. These procedures lack any previous separation steps. The calibration curves for three spectrophotometric methods are linear in the concentration range of 1–30 μg·mL−1 and 0.5–7 μg·mL−1 for pyriproxyfen and chlorothalonil successively. The recoveries ranged from 82.12–97.40% for pyriproxyfen and 81.51–97.04% for chlorothalonil with relative standard deviations less than 4.95% and 5.45% in all instances for pyriproxyfen and chlorothalonil, respectively. The results obtained from the proposed methods were compared statistically by using one-way ANOVA, and the results revealed there were no significant differences between ratio spectra and mean centering methods with the zero-crossing technique. The proposed methods are successfully applied for the simultaneous estimation of the residue of both pesticides in cucumber and cabbage samples.

Determination of Rhodium in Rhodium-Loaded Carbon Catalysts Using Microwave-Assisted Sample Digestion and ICP-OES

2014 ◽  
Vol 1033-1034 ◽  
pp. 53-56 ◽  
Author(s):  
Jun Yi Pan ◽  
Xiao Juan Wei
Keyword(s):  
Inductively Coupled Plasma ◽  
Atomic Emission ◽  
Emission Spectrometry ◽  
Plasma Atomic Emission Spectrometry ◽  
Sample Digestion ◽  
Inductively Coupled ◽  
Relative Standard ◽  
Novel Method ◽  
Carbon Catalysts

A novel method for the determination of rhodium in rhodium-loaded carbon catalyst samples was established by inductively coupled plasma atomic emission spectrometry after samples digested by microwave oven with aqua regia. Such experiment conditions were investigated as the influence of sample digestion methods, digestion time, digestion temperature and interfering ions on the determination. Under the optimized conditions, the limits of detection (LODs) of Rh for tested solutions were 9 ng mL-1. The relative standard deviations (RSDs) for Rh were 2.11 (CRh = 1 mg L-1, n = 7). The linear ranges of calibration graphs for Rh were 0 ~ 150.00 mg L-1. The proposed method was applied to determine the practical samples with good recoveries and satisfactory results.

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