Differential Spectrophotometric Determination of Calcium

1964 ◽  
Vol 10 (8) ◽  
pp. 704-720 ◽  
Author(s):  
Nathan Radin ◽  
Adalbert L Gramza
Keyword(s):  
Spectrophotometric Determination ◽  
Sample Solution ◽  
Ph Values ◽  
Beckman Spectrophotometer ◽  
Standard Solution

Abstract The appearance of kits for the determination of micro amounts of calcium stimulated our interest in the use of Eriochrome Blue SE for this analysis. A study of spectrophotometric curves indicates that, at pH values above 13.7, calcium will complex and cause a change of dye absorbance while magnesium does not complex with the dye. A differential spectrophotometric technic is described in this paper in which the spectrophotometer is set at zero absorbance with a dye-calcium standard solution or a dye-calcium sample solution as reference and the absorbance of the dye solution then measured. For a set of standards the absorbance-calcium relationship is linear. With the Beckman spectrophotometer, Model DU, it has been found that 1 part of serum to 100 parts of alkaline dye solution (100 λ of serum to 10 ml. alkaline dye solution) can be used. The technic shows greater sensitivity and accuracy than do previous methods using Eriochrome Blue SE.

Photometric Determination of pH with a Single Standard and Calculation by Nomogram

1966 ◽  
Vol 12 (12) ◽  
pp. 849-870 ◽  
Author(s):  
Donald D Van Slyke ◽  
Lawrence V Hankes ◽  
Janis John Vitols
Keyword(s):  
Human Plasma ◽  
Photometric Determination ◽  
Glass Electrode ◽  
Phenol Red ◽  
Ph Values ◽  
Slow Fading ◽  
Standard Solution ◽  
Single Standard ◽  
Hasselbalch Equation

Abstract A method is described for construction of a nomogram, based on the Henderson Hasselbalch equation, with which photometric pH values can be calculated from the absorbance of an indicator in a sample and the absorbance of the indicator in a single standard solution. Thereby the necessity of preparing calibration curves from a series of standard solutions is avoided. The procedure is particularly convenient when the stock solution of the indicator is subject to slow fading, as in the case of phenol red. An application of the procedure to the photometric determination of the pH of human plasma is detailed and the results are compared with those obtained with a glass electrode.

Spectrophotometric determination of binding constants between some aminocyclodextrins and nitrobenzene derivatives at various pH values

Tetrahedron ◽  
2002 ◽  
Vol 58 (30) ◽  
pp. 6039-6045 ◽  
Author(s):  
Paolo Lo Meo ◽  
Francesca D'Anna ◽  
Serena Riela ◽  
Michelangelo Gruttadauria ◽  
Renato Noto
Keyword(s):  
Spectrophotometric Determination ◽  
Binding Constants ◽  
Ph Values

scholarly journals Spectrophotometric determination of atenolol via oxidation and bleaching color reaction for methyl red dye

2021 ◽  
Vol 2063 (1) ◽  
pp. 012008
Author(s):  
S A Zakaria ◽  
R A Zakaria ◽  
N S Othman
Keyword(s):  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Sample Solution ◽  
Methyl Red ◽  
Suggested Procedure ◽  
Excess Quantity ◽  
Red Dye ◽  
Sensitive Spectrophotometric Method

Abstract A selective and sensitive spectrophotometric method has been suggested for the quantitative assay of atenolol (ATNL) as pure and in its manufactural formulation(Tablet). The suggested procedure included oxidation of ATNL with an excess quantity of the oxidant N-bromosuccinimide (NBS), and then the excess of NBS was occupied in bleaching the color of methyl red dye(MRD), then measuring the absorbance of remaining MRD at 518 nm. The absorbance of the unbleached color of MRD corresponds to the ATNL concentration in the sample solution. Beer’s law was followed in the range of 0.1-2.0 μg.ml−1with molar absorptivity value equal to 8.8864x104 l.mol−1. cm−1. The suggested method was applied to the assay of ATNL in commercial tablets, with satisfactory results.

Simultaneous Spectrophotometric Determination of Diphenylhydantoin and Phenobarbital in Biologic Specimens

1969 ◽  
Vol 15 (4) ◽  
pp. 323-330 ◽  
Author(s):  
Jack E Wallace
Keyword(s):  
Spectrophotometric Determination ◽  
Accurate Method ◽  
Differential Absorption ◽  
Ultraviolet Spectrophotometry ◽  
Chloroform Extraction ◽  
Ph Values ◽  
High Degree

Abstract A rapid, accurate method for determining diphenylhydantoin and phenobarbital in a single biologic sample is described. Separation of the two drugs after their initial chloroform extraction from the specimen is not required. After extraction, diphenylhydantoin is converted to benzophenone by pemanganate oxidation. Phenobarbital is determined by differential absorption between pH values of 12.0 and 10.5. Final quantitation in each case is carried out by ultraviolet spectrophotometry. Barbiturates do not interfere with the diphenylhydantoin analysis or vice versa. The method is sensitive enough for detecting subtherapeutic amounts of each compound with a high degree of specificity.

scholarly journals Spectrophotometric determination of pyridoxal and pyridoxal 5′-phosphate with 3-methyl-2-benzothiazolone hydrazone hydrochloride, and their selective assay

1969 ◽  
Vol 114 (3) ◽  
pp. 629-633 ◽  
Author(s):  
Kenji Soda ◽  
Takamitsu Yorifuji ◽  
Haruo Misono ◽  
Mitsuaki Moriguchi
Keyword(s):  
Absorption Spectra ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
The Other ◽  
Selective Determination ◽  
Characteristic Absorption ◽  
Ph Values ◽  
Alkaline Conditions ◽  
Ph Range

A spectrophotometric method with 3-methyl-2-benzothiazolone hydrazone hydrochloride was developed for the determination of pyridoxal and pyridoxal 5′-phosphate, and for the selective determination of each in the presence of the other. Pyridoxal and pyridoxal 5′-phosphate react with the reagent to yield the azine derivatives, which give characteristic absorption spectra. The highest extinction values are obtained when pyridoxal and pyridoxal 5′-phosphate are incubated at pH values of about 3·4 and 8·0 respectively; their maxima are at 430nm. (∈ 2·74×104) and 380nm. (∈ 2·24×104) respectively. The azine of pyridoxal is only slightly soluble under the neutral and alkaline conditions, whereas that of pyridoxal 5′-phosphate is substantially insoluble in the acid pH range. This difference in solubility of the azines made possible the selective determination of pyridoxal and pyridoxal 5′-phosphate. α-Oxoglutarate and pyruvate are among the substances shown not to interfere with the assay of pyridoxal; their derivatives absorb appreciably only at wavelengths below 420nm. For the assay of pyridoxal 5′-phosphate in the presence of these compounds measurement at 390nm. is necessary.

scholarly journals ANALYTICAL METHOD DEVELOPMENT AND VALIDATION OF DABIGATRAN ETEXILATE RELATED SUBSTANCE IN PHARMACEUTICAL DOSAGE FORM BY REVERSE‑PHASE – HIGH‑PERFORMANCE LIQUID CHROMATOGRAPHY

2018 ◽  
Vol 11 (10) ◽  
pp. 357
Author(s):  
Rajesh Nawale ◽  
Shankar Pol ◽  
Prashant Puranik ◽  
Anwar Daud ◽  
Vishal Rajkondawar
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Dosage Form ◽  
Dabigatran Etexilate ◽  
Sample Solution ◽  
Reverse Phase ◽  
Pharmaceutical Dosage Form ◽  
Standard Solution

Objective: The objective of the study was to develop and validate new, simple, and selective reverse-phase–high-performance liquid chromatography (RP-HPLC) method for the quantitative determination of Dabigatran Etexilate (DE) and its impurities in pharmaceutical dosage form as per the International Conference on Harmonization guidelines.Method: Chromatographic analysis was performed on Princeton SPHER-l00 C18 (250 × 4.6 mm, 5 μm) HPLC column, maintained at 50°C column temperatures, 6°C sample tray temperature, and detection monitored at 225 nm. The mobile phase consisted of acetonitrile:phosphate buffer (pH 2.5) (33:67 V/V). The flow rate was maintained at 1.0 ml/min.Results: The system suitability results indicate good performance of the system. Specificity study indicates that there is no interference of placebo and blank. The percentage relative standard deviation (RSD) of six preparations for known and unknown impurity in the sample solution is found below 10%; hence, the method is precise. The calibration curve for DE (unknown impurity), Impurity A was linear from 0.38 to 4.5 μg/ml (correlation coefficients [r2] for unknown Impurity [DE] and Impurity A are 0.996 and 0.999, respectively). The calibration curve for Impurity B and Impurity E was linear from 0.38 to 9.00 μg/ml (r2 for Impurity B and Impurity E are 0.999 and 0.999, respectively); hence, the method is linear. Accuracy for DE (unknown Impurity), Impurity A, Impurity B, and Impurity E are found within 80%–120%; hence, the method is accurate. The percentage RSD for a standard solution is found below 5% up to 24 h, and percentage impurity change in the sample solution is found below 0.1% up to 18 h; hence, standard solution is stable up to 24 h, and sample solution is stable up to 18 h.Conclusion: The developed method is new, simple, adequate, specific, precise, linear, and accurate for the determination of DE and its impurities in pharmaceutical dosage forms.

Spectrophotometric Determination of Ferric, Ferrous, and Total Iron in Drugs by Reaction with α,α′-Dipyridyl

1976 ◽  
Vol 59 (5) ◽  
pp. 1156-1161 ◽  
Author(s):  
Daniel J Sullivan
Keyword(s):  
Ascorbic Acid ◽  
Spectrophotometric Determination ◽  
Drug Dosage ◽  
Dosage Forms ◽  
Final Concentration ◽  
Total Iron ◽  
Sample Solution ◽  
Color Intensity ◽  
Drug Sample

Abstract The drug sample is dissolved in 0.2N HCl to yield a final concentration of 30 μg Fe/ml, an aliquot is reacted with α,α′-dipyridyl, and the pH is adjusted with an acetate buffer. For Fe(II), the color intensity is measured at 523 nm. For total iron, ascorbic acid is added to a separate aliquot of the sample solution, reducing all the iron present to Fe(II), which is then reacted with α,α′-dipyridyl, diluted to volume, and read at 523 nm. The Fe(III) content is determined by subtracting Fe(II) from total iron. This method is applicable to iron-containing drugs and drug dosage forms.

scholarly journals Simple, Fast, and Sensitive Method for Quantification of Tellurite in Culture Media

2010 ◽  
Vol 76 (14) ◽  
pp. 4901-4904 ◽  
Author(s):  
Roberto C. Molina ◽  
Radhika Burra ◽  
José M. Pérez-Donoso ◽  
Alex O. Elías ◽  
Claudia Muñoz ◽  
...  
Keyword(s):  
Spectrophotometric Determination ◽  
Chemical Method ◽  
Culture Media ◽  
Elemental Tellurium ◽  
Ph Values ◽  
Mediated Reduction ◽  
Sensitive Method

ABSTRACT A fast, simple, and reliable chemical method for tellurite quantification is described. The procedure is based on the NaBH4-mediated reduction of TeO3 2− followed by the spectrophotometric determination of elemental tellurium in solution. The method is highly reproducible, is stable at different pH values, and exhibits linearity over a broad range of tellurite concentrations.

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