scholarly journals Second-Derivative Spectrometric Determination of Urea in Milk Using the Diacetyl Monoxime Reagent

2010 ◽  
Vol 93 (2) ◽  
pp. 485-491 ◽  
Author(s):  
Steven A Nyanzi ◽  
Maureen Isiko ◽  
Francis Kateregga ◽  
Wolfgang Schwack
Keyword(s):  
Correlation Coefficients ◽  
Colorimetric Determination ◽  
Second Derivative ◽  
Linear Calibration ◽  
Colored Complex ◽  
Spectral Bands ◽  
Sensitivity And Selectivity ◽  
Diacetyl Monoxime ◽  
Second Derivative Method

Abstract The application of derivative spectrometry to resolve overlapping spectra and improve the sensitivity and selectivity of the colorimetric determination of urea in milk using diacetyl monoxime is presented. With first-derivative (1D) spectrometry, the max of the colored complex was established to be 525 nm. The absorption band at max 525 nm in normal absorption (0D) spectrometry was resolved into three clearly distinct spectral bands with minima at 497, 530, and 566 nm with second-derivative (2D) spectrometry. With the second-derivative (2D530) technique, the depth of the trough of the strongest signal at 530 nm was used to determine urea in milk samples. Linear calibration curves for urea were obtained over a concentration range of 0.21.4 mg/L, with correlation coefficients greater than 0.999. The LOD and LOQ of the method were 0.01 and 0.03 mg/L, respectively. Recoveries of 99100 of spiked urea in milk with RSD values below 2.0 were obtained. The second-derivative method is simple, affordable, sensitive, and selective for the determination of urea in milk.

Colorimetric determination of urea v2

2021 ◽  
Author(s):  
noah.langenfeld not provided ◽  
Laurenpayne not provided ◽  
Bruce Bugbee
Keyword(s):  
Colorimetric Determination ◽  
Diacetyl Monoxime

This protocol measures the absorbance of urea in solution in complexation with diacetyl monoxime at 520 nm and is linearly proportional to concentration up to 5 mM urea.

Different Spectrophotometric and Chromatographic Methods for Determination of Mepivacaine and Its Toxic Impurity

2017 ◽  
Vol 100 (5) ◽  
pp. 1392-1399 ◽  
Author(s):  
Nada S Abdelwahab ◽  
Nehal F Fared ◽  
Mohamed Elagawany ◽  
Esraa H Abdelmomen
Keyword(s):  
Particle Size ◽  
Stationary Phase ◽  
Second Derivative ◽  
Spectrophotometric Measurement ◽  
Spectrophotometric Methods ◽  
Derivative Method ◽  
Tlc Plates ◽  
Second Derivative Method ◽  
Developing System

Abstract Stability-indicating spectrophotometric, TLC-densitometric, and ultra-performance LC (UPLC) methods were developed for the determination of mepivacaine HCl (MEP) in the presence of its toxic impurity, 2,6-dimethylanaline (DMA). Different spectrophotometric methods were developed for the determination of MEP and DMA. In a dual-wavelength method combined with direct spectrophotometric measurement, the absorbancedifference between 221.4 and 240 nm was used for MEPmeasurements, whereas the absorbance at 283 nm was used for measuring DMA in the binary mixture. In the second-derivative method, amplitudes at 272.2 and 232.6 nm were recorded and used for the determination of MEP and DMA, respectively. The developed TLC-densitometric method depended on chromatographic separation using silica gel 60 F254 TLC plates as a stationary phase and methanol–water–acetic acid (9 + 1 + 0.1, v/v/v) as a developing system, with UV scanning at 230 nm. The developed UPLC method depended on separation using a C18 column (250 × 4.6 mm id, 5 μm particle size) as a stationary phase and acetonitrile–water (40 + 60, v/v; pH 4 with phosphoric acid) as a mobilephase at a flow rate of 0.4 mL/min, with UV detection at 215 nm. The chromatographic run time was approximately 1 min. The proposed methods were validated with respect to International Conference on Harmonization guidelines regarding precision, accuracy, ruggedness, robustness, and specificity.

scholarly journals Utility of N-Bromosuccinimide as a Green Chemical Reagent for Determination of H2-Receptor Antagonists in their Pharmaceutical Dosage Forms

2019 ◽  
Vol 27 (1) ◽  
pp. 47-64
Author(s):  
Ahmed I. Hassan
Keyword(s):  
Correlation Coefficients ◽  
Dosage Forms ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Receptor Antagonists ◽  
Pharmaceutical Dosage Forms ◽  
Drug Concentrations ◽  
Environmentally Safe ◽  
The Common

Abstract An environmentally safe, simple and robust spectrophotometric method has been developed for determination of H2-receptor antagonists namely: cimetidine (CIM), famotidine (FAM), nizatidine (NIZ), and ranitidine hydrochloride (RAN). The method was depend on the reaction of the studied drugs with N-bromosuccinimide (NBS), environmentally friendly reagent, and the excess NBS was measured by its reaction with phloroglucinol to give a yellow chromogenic product (λmax at 435 nm). The absorption intensity decrease (ΔA) was correlated with drug concentrations in the sample solutions. By using of the optimum conditions, linear calibration curves with good correlation coefficients (0.9958–0.9998) were found between the measured ΔA values and the corresponding drugs concentrations in the range of 12-80 μg mL−1. Limits of detection were in the range 1.31-2.21 μg mL−1. The proposed method was validated and successfully applied for the analysis of the above mentioned drugs in their bulk and pharmaceutical dosage forms with good recoveries (98.5 ± 0.98 to 102.5 ± 0.79%). No interferences were obtained from the common excipients. The proposed method was successfully applied for the analysis of H2RAs in their dosage forms and the results were comparable with that obtained by the official methods.

Colorimetric Determination of 3-Amino-l,2,4-Triazole in Grain or Meal

1982 ◽  
Vol 65 (1) ◽  
pp. 24-27
Author(s):  
Michel Galoux ◽  
Jean-C Van Damme ◽  
Albert Bernes
Keyword(s):  
Sulfuric Acid ◽  
Limit Of Detection ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
Colored Complex ◽  
Adsorption Desorption

Abstract This colorimetric method for the determination of 3-amino-l,2,4-triazole in grain or meal is a modification of the Storherr and Burke method. The herbicide is extracted from grain with methanol, and purified by adsorption-desorption on resin. The extract is cleaned by digestion with sulfuric acid and clarified with charcoal. The colored complex formed by coupling with N-(1-naphthyl)ethylenediammonium dichloride is measured spectrophotometrically at 455 nm. The limit of detection is 0.05 ppm.

scholarly journals Chemometric Methods for the Simultaneous Determination of Some Water-Soluble Vitamins

2011 ◽  
Vol 94 (2) ◽  
pp. 467-481 ◽  
Author(s):  
Abdel-Maaboud I Mohamed ◽  
Horria A Mohamed ◽  
Niveen A Mohamed ◽  
Marwa R El-Zahery
Keyword(s):  
Correlation Coefficients ◽  
Water Soluble ◽  
Multivariate Methods ◽  
Linear Calibration ◽  
Principal Components Regression ◽  
Regression Methods ◽  
Spectrophotometric Methods ◽  
First Derivative ◽  
Accuracy And Precision

Abstract Two spectrophotometric methods, derivative and multivariate methods, were applied for the determination of binary, ternary, and quaternary mixtures of the water-soluble vitamins thiamine HCl (I), pyridoxine HCl (II), riboflavin (III), and cyanocobalamin (IV). The first method is divided into first derivative and first derivative of ratio spectra methods, and the second into classical least squares and principal components regression methods. Both methods are based on spectrophotometric measurements of the studied vitamins in 0.1 M HCl solution in the range of 200500 nm for all components. The linear calibration curves were obtained from 2.590 g/mL, and the correlation coefficients ranged from 0.9991 to 0.9999. These methods were applied for the analysis of the following mixtures: (I) and (II); (I), (II), and (III); (I), (II), and (IV); and (I), (II), (III), and (IV). The described methods were successfully applied for the determination of vitamin combinations in synthetic mixtures and dosage forms from different manufacturers. The recovery ranged from 96.1 1.2 to 101.2 1.0 for derivative methods and 97.0 0.5 to 101.9 1.3 for multivariate methods. The results of the developed methods were compared with those of reported methods, and gave good accuracy and precision.

The colorimetric determination of cyanate ion with hydroxylamine-diacetyl monoxime

1974 ◽  
Vol 23 (9) ◽  
pp. 1071-1073
Author(s):  
Keiichiro ISHII ◽  
Takeji IWAMOTO ◽  
Kazuhiko YAMANISHI
Keyword(s):  
Colorimetric Determination ◽  
Diacetyl Monoxime

scholarly journals Determination of the Dissociation Constants of Metformin from a Second Derivative UV Spectrum

2020 ◽  
Vol 11 (1) ◽  
pp. 790-796 ◽  
Author(s):  
Khalid Waleed S. Al-Janabi ◽  
Ali Khalil Mahmood ◽  
Hasan M. Luaibi
Keyword(s):  
Aqueous Solution ◽  
Dissociation Constants ◽  
Correlation Coefficients ◽  
Pharmaceutical Compounds ◽  
Second Derivative ◽  
Uv Spectrum ◽  
Established Method ◽  
Ultraviolet Spectra ◽  
The Mean

An environmentally begnin second derivative spectrometric approach was developed for the estimation of the dissociation constants pKa(s) of metformin, a common anti-diabetic drug.  The ultraviolet spectra of the aqueous solution of metformin were measured at different acidities, then the second derivative of each spectrum was graphed. The overlaid second derivative graphs exhibited two isobestic points at 225.5 nm and 244 nm pointing out to the presence of two dissociation constants for metformin pKa1 and pKa2, respectively. The method was validated by evaluating the reproducibility of the acquired results by comparing the estimated values of the dissociation constants of two different strategies that show excellent matching. As well as, the whole procedure was repeated with a new set of standard solutions and buffers for further verification. The average calculated values of pKa1 and pKa2 were found to be 2.72±0.01 and 11.61±0.08, with correlation coefficients ( R2) of 0.9916 and 0.9614, respectively. The established method was fast, affordable, reproducible, and the mean pKa values obtained were accurate and can be applied for the estimation of the dissociation constants of other active pharmaceutical compounds

scholarly journals A SIMPLE SPECTROPHOTOMETRIC METHOD FOR THE TRACE DETERMINATION OF COPPER(II)

2012 ◽  
Vol 09 (18) ◽  
pp. 50-56
Author(s):  
Raghavendra Guru Prasad ALURU ◽  
Srilalitha VINNAKOTA ◽  
Ramana Kumar KAKARLA ◽  
RAO KRISHNA RAO Ravindranath LAKSHMANA
Keyword(s):  
Spectrophotometric Method ◽  
Trace Determination ◽  
Method Detection Limit ◽  
Linear Calibration ◽  
Limit Of Quantification ◽  
Colored Complex ◽  
Metabolic Functions ◽  
Greenish Yellow ◽  
Determination Of Copper

Copper is an essential trace nutrient for plants, animals. It is very essential at lower levels for specific metabolic functions, but is harmful at elevated levels. Significant amount of copper is widespread in the environment form variety of sources. A simple spectrophotometric method is presented for the determination of trace amounts of copper using salicyl salicyclic acid hydrazone (SSAH) as a spectrophotometric reagent. The proposed method has the advantages of sensitivity, rapidity and selectivity without any prior separation or extraction. The method was based on the reaction between SSAH and Cu(II) in acidic medium to produce a greenish-yellow colored complex. The complex has an absorption maximum at 420 nm. Beer’s law is obayed in the concentration range 0.2497 to 2.2471 μg mL−1. Several parameters like stability constant (1.13×107), molar absorption coefficient (8.560×104 L mol–1cm–1), Sandell’s sensitivity (0.0007 μg cm–2), linear calibration range, stoichiometry of the complex (1:1), method detection limit (0.0299 μg mL–1), limit of quantification (0.0598 μg mL–1), standard deviation (2.624%–3.567%) etc were calculated and presented. The effect of foreign ions on the determination was presented. The method was successfully applied for the determination of copper in spiked water samples and alloy samples.

A New Simple Semimicro Method for Colorimetric Determination of Urea

1963 ◽  
Vol 9 (1) ◽  
pp. 102-108 ◽  
Author(s):  
J J Coulombe ◽  
L Favreau
Keyword(s):  
Acid Medium ◽  
Rapid Method ◽  
Room Temperature ◽  
Colorimetric Determination ◽  
Red Color ◽  
Color Complex ◽  
Blood Filtrate ◽  
Diacetyl Monoxime

Abstract A new simple and rapid method for quantitative semimicro determination of blood urea is presented. Diacetyl monoxime and thiosemicarbazide form in acid medium with urea a red color complex with a maximum adsorption at 530 mµ stable at room temperature and requiring 0.2 ml. of 1:10 blood filtrate.

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