scholarly journals Beyond Beer's Law: Revisiting the Lorentz‐Lorenz Equation

ChemPhysChem ◽  
2020 ◽  
Vol 21 (12) ◽  
pp. 1218-1223 ◽  
Author(s):  
Thomas G. Mayerhöfer ◽  
Jürgen Popp
Keyword(s):  
Lorenz Equation ◽  
Beer's Law ◽  
Beer’S Law

Novel UV Spectrophotometric Method for the Quantitative Analysis of CefpodoximeProxetil in Pharmaceutical Formulations by First Derivative Technique

2017 ◽  
Vol 8 (03) ◽  
Author(s):  
Potdar S. S. ◽  
Karajgi S. R. ◽  
Simpi C. C. ◽  
Kalyane N. V.
Keyword(s):  
Quantitative Analysis ◽  
Spectrophotometric Method ◽  
Dosage Form ◽  
Pharmaceutical Formulations ◽  
First Derivative ◽  
Good Linearity ◽  
Beer's Law ◽  
Beer’S Law ◽  
Tablet Dosage ◽  
Ich Guideline

The spectrophotometric method for estimation of CefpodoximeProxetil employed first derivative amplitude UV spectrophotometric method for analysis using methanol as solvent for the drug. CefpodoximeProxetil has absorbance maxima at 235nm and obeys Beer’s law in concentration range 10-50µg/ml with good linearity i.e. r2 about 0.999. The recovery studies established accuracy of the proposed method; result validated according to ICH guideline. Results were found satisfactory and reproducible. The method was successfully for evaluation of CefpodoximeProxetil in tablet dosage form without interference of common excipients.

scholarly journals Estimation of Tadalafil Using Derivative Spectrophotometry in Bulk Material and in Pharmaceutical Formulation

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Zamir G. Khan ◽  
Amod S. Patil ◽  
Atul A. Shirkhedkar
Keyword(s):  
Wavelength Range ◽  
Area Under Curve ◽  
Pharmaceutical Formulation ◽  
Second Order ◽  
Order Derivative ◽  
Uv Spectrophotometry ◽  
First Order ◽  
Beer's Law ◽  
Beer’S Law ◽  
Derivative Uv Spectrophotometry

Four simple, rapid, accurate, precise, reliable, and economical UV-spectrophotometric methods have been proposed for the determination of tadalafil in bulk and in pharmaceutical formulation. “Method A” is first order derivative UV spectrophotometry using amplitude, “method B” is first order derivative UV spectrophotometry using area under curve technique, “method C” is second order derivative UV spectrophotometry using amplitude, and “method D” is second order derivative UV spectrophotometry using area under curve technique. The developed methods have shown best results in terms of linearity, accuracy, precision, and LOD and LOQ for bulk drug and marketed formulation as well. In N,N-dimethylformamide, tadalafil showed maximum absorbance at 284 nm. For “method A” amplitude was recorded at 297 nm while for “method B” area under curve was integrated in the wavelength range of 290.60–304.40 nm. For “method C” amplitude was measured at 284 nm while for “method D” area under curve was selected in the wavelength range of 280.80–286.20 nm. For methods A and B, tadalafil obeyed Lambert-Beer’s law in the range of 05–50 μg/mL while for “methods C and D”, tadalafil obeyed Lambert-Beer’s law in the range of 20–70 μg/mL, and-for “methods A, B, C, and D” the correlation coefficients were found to be > than 0.999.

scholarly journals A spectrophotometric method for determination of fluorophore-to-protein ratios in conjugates of the blue fluorophore 7-amino-4-methylcoumarin-3-acetic acid (AMCA)

1990 ◽  
Vol 38 (1) ◽  
pp. 87-94 ◽  
Author(s):  
M W Wessendorf ◽  
S J Tallaksen-Greene ◽  
R M Wohlhueter
Keyword(s):  
Acetic Acid ◽  
Optical Density ◽  
Extinction Coefficient ◽  
Spectrophotometric Method ◽  
Extinction Coefficients ◽  
Beer's Law ◽  
Beer’S Law ◽  
The Given

7-Amino-4-methylcoumarin-3-acetic acid (AMCA) has been found to be a useful fluorophore for immunofluorescence. The present study describes a spectrophotometric method for determining the ratio of moles AMCA to moles protein (or the f/p ratio) in an AMCA-conjugated IgG. The concentration of a substance absorbing light can be determined spectrophotometrically using Beer's Law: Absorbance = Concentration x Extinction coefficient. From Beer's law, one can derive the following formula for determining the f/p ratio of AMCA-IgG conjugates: f/p = (epsilon 280IgG).A350 - (epsilon 350IgG).A280/(epsilon 350AMCA).A280 - (epsilon 280AMCA).A350 where A is the optical density of the conjugate at the given wavelength and epsilon is the extinction coefficient of a substance at the wavelength specified. Using conjugates of model proteins, it was found that the extinction coefficients of the AMCA moiety of AMCA-conjugated protein were 1.90 x 10(4) at 350 nm and 8.29 x 10(3) at 280 nm. Similarly, it was found that the extinction coefficients of swine IgG were 1.56 x 10(3) at 350 nm and 1.26 x 10(5) at 280 nm. Thus, for AMCA-conjugated swine IgG: f/p = (1.26 x 10(5)).A350 - (1.56 x 10(3)).A280/(1.47 x 10(4)).A280 - (6.42 x 10(3)).A350 [corrected]. Based on this formula, the f/p ratios of some AMCA-IgG conjugates useful for immunohistochemistry have been found to range between 6 and 24.

scholarly journals Rapid Spectrophotometric Determination of Phenoxazine

2010 ◽  
Vol 7 (2) ◽  
pp. 1001-1005
Author(s):  
Baghdad Science Journal
Keyword(s):  
Detection Limit ◽  
Spectrophotometric Determination ◽  
Acidic Medium ◽  
Absorption Maximum ◽  
Aqueous Samples ◽  
Economic Method ◽  
Beer's Law ◽  
Beer’S Law ◽  
The Stability

A rapid high sensitive and inexpensive economic method has been developed for the Determination of phenoxazine by using molecular spectrophotometry. The method is based on the oxidation of phenoxazine by potassium (meta)periodate in acidic medium. The oxidation conditions were selected to enhance the sensitivity and the stability of the pink colored species which shows an absorption maximum at 530 nm. The Beer’s law was obeyed for phenoxazine concentration range from 1 to 6 µg mL-1 with 0.003 µg mL-1 detection limit and provided variation coefficients between 0.4 to 1.7 %. This method was successfully applied for the determination of phenoxazine in aqueous samples

THE DETERMINATION OF PHOSPHOLIPID PHOSPHORUS

1949 ◽  
Vol 27e (3) ◽  
pp. 159-163 ◽  
Author(s):  
J. M. R. Beveridge ◽  
S. E. Johnson
Keyword(s):  
Color Stability ◽  
Accurate Method ◽  
Inorganic Phosphorus ◽  
Strict Adherence ◽  
Beer's Law ◽  
Beer’S Law ◽  
Excellent Color ◽  
Colorimetric Procedure

A simple accurate method for the determination of phospholipid phosphorus is described. Conditions for the digestion of phospholipid have been developed permitting the utilization of a colorimetric procedure for inorganic phosphorus that is characterized by excellent color stability and strict adherence to Beer's law over a range of 0 to 65 μgm. of phosphorus.

Observations on the Apparent Failure of Beer's Law Near the Transmission Limit of a Solvent

Science ◽  
1951 ◽  
Vol 114 (2970) ◽  
pp. 576-577
Author(s):  
J. M. Vandenbelt ◽  
Carola Henrich ◽  
Shirley L. Bash
Keyword(s):  
Beer's Law ◽  
Beer’S Law

Observations on the Apparent Failure of Beer's Law Near the Transmission Limit of a Solvent

Science ◽  
1951 ◽  
Vol 114 (2970) ◽  
pp. 576-577
Author(s):  
J. M. Vandenbelt ◽  
Carola Henrich ◽  
Shirley L. Bash
Keyword(s):  
Beer's Law ◽  
Beer’S Law
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