scholarly journals MICRO DETERMINATION OF DOPAMINE IN BIOLOGICAL SAMPLES BY COUPLING REACTION

2018 ◽  
Vol 22 (4) ◽  
Author(s):  
AHMED JASSIM MUKLIVE AL-OGAIDI
Keyword(s):  
Mole Fraction ◽  
Biological Samples ◽  
Azo Dye ◽  
Coupling Reaction ◽  
Stability Factor ◽  
Relative Standard ◽  
The Stability ◽  
Fraction Method ◽  
Orange Color

The paper presents the development of an analytical method to determine dopamine by coupling reaction with diazotized solution of 4-Aminoantipyrine in basic media to give a compound with a single azo dye salt having orange color soluble in water.  A calibration curve for a range of concentration (9.14x10<sup>-5</sup> – 2.28x10<sup>-3</sup> μg.mL<sup>-1</sup>) was realized and the value of molar absortivity was 1.5x103 L.mol<sup>-1</sup>.cm<sup>-1</sup>, with a relative standard deviation more than 1.26% and a recovery 98.77%. As we study the nature of the azo dye by mole fraction method, from the practical value we found that the mole fraction of the dye compound is 1:1 (dopamine: 4- amino antipyrine) and the stability factor reach to 1.4x106 L.mol<sup>-1</sup>. The described procedure is very simple, low-time-consuming, provides high throughput of examined samples, and could be used for routine screening and confirmatory analyses as well. The method was successfully validated to the analysis of the dopamine in biological samples.

scholarly journals MICRO DETERMINATION OF DOPAMINE IN BIOLOGICAL SAMPLES BY COUPLING REACTION

2016 ◽  
Vol 22 (4) ◽  
pp. 7-12
Author(s):  
AHMED JASSIM MUKLIVE AL-OGAIDI
Keyword(s):  
Mole Fraction ◽  
Biological Samples ◽  
Azo Dye ◽  
Coupling Reaction ◽  
Stability Factor ◽  
Relative Standard ◽  
The Stability ◽  
Fraction Method ◽  
Orange Color

The paper presents the development of an analytical method to determine dopamine by coupling reaction with diazotized solution of 4-Aminoantipyrine in basic media to give a compound with a single azo dye salt having orange color soluble in water. A calibration curve for a range of concentration (9.14x10-5 – 2.28x10-3 μg.mL-1) was realized and the value of molar absortivity was 1.5x103 L.mol-1.cm-1, with a relative standard deviation more than 1.26% and a recovery 98.77%. As we study the nature of the azo dye by mole fraction method, from the practical value we found that the mole fraction of the dye compound is 1:1 (dopamine: 4- amino antipyrine) and the stability factor reach to 1.4x106 L.mol-1. The described procedure is very simple, low-time-consuming, provides high throughput of examined samples, and could be used for routine screening and confirmatory analyses as well. The method was successfully validated to the analysis of the dopamine in biological samples.

scholarly journals Cloud point extraction method for the sensitive determination of metoclopramide hydrochloride in pharmaceutical dosage forms

2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Wasan A. Al-Uzri ◽  
Hind Hadi
Keyword(s):  
Cloud Point ◽  
Azo Dye ◽  
Cloud Point Extraction ◽  
Coupling Reaction ◽  
Extraction Process ◽  
Dosage Forms ◽  
Pharmaceutical Dosage Forms ◽  
Relative Standard ◽  
Metoclopramide Hydrochloride

In this work, a simple and very sensitive cloud point extraction (CPE) process was developed for the determination of trace amount of metoclopramide hydrochloride (MTH) in pharmaceutical dosage forms. The method is based on the extraction of the azo-dye results from the coupling reaction of diazotized MTH with p-coumaric acid (p-CA) using nonionic surfactant (Triton X114). The extracted azo-dye in the surfactant rich phase was dissolved in ethanol and detected spectrophotometrically at λmax 480 nm. The reaction was studied using both batch and CPE methods (with and without extraction) and a simple comparison between the two methods was performed. The conditions that may be affected by the extraction process and the sensitivity of methods were carefully studied. Using optimal conditions, the linearity of calibration curves was in the range of 0.4-13 and 0.05-4µg/mL and limits of detection of 0.044 and 0.028 µg/mL of MTH for batch and CPE methods respectively. Average recoveries for samples were detected to be between 97-101 %for both methods, with the relative standard deviation (RSD %) best than 2.7 % and 4.5 % for both methods, respectively. The suggested methods were applied successfully for assay of MTH in commercial pharmaceutical tablets.

Determining the Norton’s Equivalent Model of Distribution System with Distributed Generation (DG) for Stability Analysis

2019 ◽  
Vol 12 (2) ◽  
pp. 190-198
Author(s):  
Sunny Katyara ◽  
Lukasz Staszewski ◽  
Faheem Akhtar Chachar
Keyword(s):  
Distributed Generation ◽  
Normal Condition ◽  
Distribution System ◽  
Distribution Networks ◽  
Equivalent Model ◽  
Stability Factor ◽  
Matlab Simulation ◽  
The Stability ◽  
Stability Issues

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system’s parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton’s equivalent model of distribution system with DG, considering from receiving end. Norton’s model of distribution system can be determined either from its complete configuration or through an algorithm using system’s voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system’s impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton’s model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.

scholarly journals Determination of Sodium Cromoglycate by a New Kinetic Spectrophotometric Method in Biological Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Mohsen Keyvanfard ◽  
Khadijeh Alizad ◽  
Razieh Shakeri
Keyword(s):  
Standard Deviation ◽  
Sodium Cromoglycate ◽  
Spectrophotometric Method ◽  
Calibration Curve ◽  
Biological Samples ◽  
Limit Of Detection ◽  
Micellar Medium ◽  
Relative Standard ◽  
Kinetic Spectrophotometric

A new kinetic spectrophotometric method is described for the determination of ultratrace amounts of sodium cromoglycate (SCG). The method based on catalytic action of SCG on the oxidation of amaranth with periodate in acidic and micellar medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of the amaranth at 518 nm, for the first 4 min from initiation of the reaction. Calibration curve was linear in the range of 4.0−36.0 ng mL−1SCG. The limit of detection is 2.7 ng mL−1SCG. The relative standard deviation (RSD) for ten replicate analyses of 12, 20, and 28 ng mL−1SCG was 0.40%, 0.32%, and 0.53%, respectively. The proposed method was used for the determination of SCG in biological samples.

scholarly journals Spectrophotometric indicators of the stability of anthocyanin-containing extracts depending on the color of plant materials

2020 ◽  
Vol 31 (2) ◽  
pp. 88-92
Author(s):  
Vladimir Mikhailovich Koldaev ◽  
Artem Yurevich Manyakhin ◽  
Petr Semenovich Zorikov
Keyword(s):  
Hydrochloric Acid ◽  
Stability Factor ◽  
Plant Materials ◽  
Herbal Preparations ◽  
Violet Color ◽  
The Stability ◽  
Selection Of ◽  
Factor Coefficient ◽  
Anthocyanin Degradation

AbstractThis paper aims at spectrophotometric determination of changes in stability of extractable anthocyanins during drying of plant materials depending on their color. Raw and dried colored parts of 50 plant species from 25 families were used for the study. The extracts were prepared over 95% ethanol acidified with hydrochloric acid (pH ~ 1). The absorption spectra were registered within the range of 210 to 680 nm. The extinction variability factor, coefficient of intensity absorption relative and generalized stability factor were used to determine the anthocyanin degradation. The highest values of the stability factor were obtained for the extracts from fruit shells of burgundy or violet color within the range of 0.934±0.024 to 0.973±0.024, while the extracts from flower petals of the same care featured the stability factor that was 1.19 to 1.44 times less. The values of the stability factor of the extracts from black, red and blue materials are 1.15 to 1.19 times, 1.74 to 2.48 times and 4.65 to 4.84 times less respectively than those of the extracts from violet-burgundy materials. It is appropriate to apply the spectrophotometric factors of anthocyanins stability used in this study to selection of promising plants for industrial cultivation as material of anthocyanin-containing herbal preparations. The most stable anthocyanins are those of burgundy-purple and black fruits.

scholarly journals SYNTHESIS OF NEW SUBSTITUTED PROCAINE HYDROCHLORIDE COMPOUNDS AND THEIR USE IN SPECTROPHOTOMETRIC DETERMINATION OF TETRACYCLINE HYDROCHLORIDE THROUGH DIAZOTIZATION-COUPLING REACTIONS

2021 ◽  
Vol 18 (39) ◽  
pp. 14-32
Author(s):  
Hind Sadiq Al-WARD ◽  
Mouayed Qassssim AL-ABACHI ◽  
Mohammed Rifaat AHMED
Keyword(s):  
Stability Constant ◽  
Thermodynamic Parameters ◽  
Coupling Reaction ◽  
Water Soluble ◽  
Procaine Hydrochloride ◽  
Effect Of Temperature ◽  
Basic Medium ◽  
Fast Method ◽  
The Stability

Background: Tetracycline is one of the most important antibiotics. It is used to treat many different bacterial infections. It is often used in treating severe acne, or sexually transmitted diseases such as syphilis, gonorrhea, or chlamydia. In some cases, tetracycline is used when penicillin or another antibiotic cannot be used to treat serious infections such as the ones caused by Bacillus anthracis, Listeria, Clostridium, Actinomyces. Aim: synthesized a new novel reagent used to determine TCH spectrophotometrically by using diazonium and coupling reaction. Methods: Four new substituted procaine derivatives were prepared by simple organic methods using aniline derivatives. A spectrophotometric approach was established for the micro-determination of TCH. The stoichiometry was investigated using mole ratio and continuous variation methods, and the stability constant was also estimated. The ΔG, ΔH, and ΔS were determined as thermodynamic parameters for evaluating the effect of temperature on the reaction. Results: Substituted procaine derivatives were prepared, and o-hydroxy procaine seems to be the best reagent used to determine TCH by diazotization and coupling reaction. The result was a yellow water-soluble dye with a maximum absorbance of 380 nm. The reaction conditions were studied and optimized. Beers law was obeyed over a concentration range (2.5–50) μg.mL-1 for TCH. The molar absorptivity was (14.4669.103) L.mol-1.cm-1, and the detection limit was (0.5052) μg.mL-1. The stoichiometry of the formed product was found 1:1 (o-hydroxyprocaine: TCH). The stability constant indicated that the product formed was stable, and the thermodynamic parameters showed that the diazonium salt reaction was preferred to occur at a low temperature. Conclusions: a simple, accurate, and fast method was developed to determine TCH in pure form and pharmaceuticals by coupling the TCH with a newly synthesized procaine derivative reagent (o-hydroxy procaine) in a basic medium.

Spectrophotometric Determination of Chlorpromazine Hydrochloride Using 4-Nitroanilline by Oxidative Coupling Reaction

2019 ◽  
Vol 16 (1(Suppl.)) ◽  
pp. 0194
Author(s):  
Al-rashidy Et al.
Keyword(s):  
Oxidative Coupling ◽  
Analytical Data ◽  
Reaction Medium ◽  
Coupling Reaction ◽  
Suggested Method ◽  
Sensitivity Index ◽  
Chlorpromazine Hydrochloride ◽  
Oxidative Coupling Reaction ◽  
Relative Standard

A simple, rapid spectrophotometric method has been established for the determination of chlorpromazine hydrochloride (CPZ) in its pure form and in a tablet formulations. The  suggested  method  is  based  on  the  oxidative coupling  reaction  with4-nitroainlline using KIO3 in acidic solution to produce a violet colored product with maximum absorption at λ=526 nm.The  analytical data  obtained  throughout  this  study  could  be  summarid  as  follows:  1ml of 1M HCl (pH=2.2), 1 ml  of  4-nitroanilline (1x10-2M), and 1.5ml  of (1x10-2)KIO3 per 25 ml reaction medium. The order of additions, coupling reaction time, and temperature in addition to the type of solvent were studied. The Beer′s law is obeyed over the concentration range of(5–40) µg ml-1, but the detection limit and quantification limit are 0.34 besides 1.03 µg ml-1 respectively. The correlation coefficient (r) for the calibration graph was found to be 0.9980, molar absorptivity of 10. 25 × 103 L.mol -1.cm-1, and Sandell′s sensitivity index of 0.03467 µg.cm-2. The precision and accuracy of the method were tested by calculating the percentage of relative standard deviation (RSD%) (<1.831%) and the average recovery percent (99.22%) average error percent Erel%(0.558). Direct and standard addition procedures were applied to both standards and specimens of pharmaceutical and the results indicate that the suggested method was successfully applied for the determination of CPZ.

Stability-Indicating Liquid Chromatographic Procedure for Determination of Allantoin in Cosmetic Lotion

1988 ◽  
Vol 71 (2) ◽  
pp. 290-294
Author(s):  
Ramesh J Trivedi
Keyword(s):  
Degradation Products ◽  
Glyoxylic Acid ◽  
Uv Detector ◽  
Stability Indicating ◽  
Assay Procedure ◽  
Relative Standard ◽  
The Stability ◽  
Chromatographic Parameters ◽  
Liquid Chromatographic

Abstract A sensitive, specific liquid chromatographic (LC) procedure was developed for determination of allantoin [(2,5-dioxo-4--imidaazolidinyl) urea or 5-ureidohydantion] in cosmetic lotion. A reverse-phase, ionsuppression mechanism separated allantoin from interfering constituents of the sample matrix, and the compound was determined with a UV detector at 240 nm with a sensitivity limit of ((.20 mg/mL. The chromatographic parameters were optimized for retention time, efficiency, and relative response to the analyte. The assay procedure was validated with spiked laboratory-prepared samples at 100 ± 15% levels. An average recovery of 99.4% with a relative standard deviation of 1.5% (n = 7) was obtained. The stability-indicating characteristics of the method were established by recovery study (99.8%) of samples spiked with known degradation products (urea, allantoic acid, and glyoxylic acid).

Determination of the Stability of the AIO+ Complex in Alkali Halide Melts*

1984 ◽  
Vol 39 (5) ◽  
pp. 499-502 ◽  
Author(s):  
C. M. Wai ◽  
M. Blander
Keyword(s):  
Free Energy ◽  
Bond Strength ◽  
Mole Fraction ◽  
Thermodynamic Data ◽  
Alkali Halide ◽  
Formation Constant ◽  
Activation Technique ◽  
Eutectic Mixtures ◽  
The Stability

The solubilities of Al182O3 in LiCl-KCl eutectic mixtures containing dissolved AlCl3 were measured using a sensitive proton activation technique. The results are consistent with the presence of an A10+ species at 4.7 x 10-5 mole fraction with AlCl3 at 10-2 mole fraction. When combined with other thermodynamic data, these solubilities are used to deduce a formation constant for the A10+ species from Al3+ and O2- ions of 1.94 x 1022 (in mole fraction units) and a specific bond free energy ("bond strength") of 300 kJ mol-1

scholarly journals Spectrophotometric Method for Determination of Paraquat in Food and Biological Samples

1997 ◽  
Vol 80 (2) ◽  
pp. 388-391 ◽  
Author(s):  
Ritu Kesari ◽  
Manish Rai ◽  
Vinay Kumar Gupta
Keyword(s):  
Standard Deviation ◽  
Metal Ions ◽  
Relative Standard Deviation ◽  
Alkaline Medium ◽  
Spectrophotometric Method ◽  
Biological Samples ◽  
Molar Absorptivity ◽  
Relative Standard ◽  
Sensitive Spectrophotometric Method

Abstract A sensitive spectrophotometric method was developed for determination of paraquat, a widely used herbicide. Paraquat was reduced with glucose in an alkaline medium, and the blue radical ion obtained was measured at 600 nm. Beer’s law was obeyed at 0.1–1.2 ppm paraquat. The molar absorptivity was 1.26 × 105 L mol-1 cm-1. The standard deviation and relative standard deviation were ± 0.007 and 2.0%, respectively, for 5 μg paraquat/10 mL analyzed over 7 days. The method was free from interference by other commonly used pesticides and metal ions. The method may be used to the determine paraquat in plants, fruits, grains, water, blood, and urine.

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