scholarly journals Determination of methyldopa in pharmaceutical formulations by combined spot test-diffuse reflectance spectroscopy

2006 ◽  
Vol 17 (4) ◽  
pp. 674-679 ◽  
Author(s):  
Paulo Roberto S. Ribeiro ◽  
Leonardo Pezza ◽  
Helena R. Pezza
Keyword(s):  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Pharmaceutical Formulations ◽  
Reflectance Spectroscopy ◽  
Spot Test

scholarly journals Determination of hydrochlorothiazide in pharmaceutical formulations by diffuse reflectance spectroscopy

2005 ◽  
Vol 30 (2) ◽  
pp. 17-24 ◽  
Author(s):  
M. A. Gotardo ◽  
L. Pezza ◽  
H. R. Pezza
Keyword(s):  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Limit Of Detection ◽  
Heating Temperature ◽  
Pharmaceutical Formulations ◽  
The United States ◽  
Reflectance Spectroscopy ◽  
Heating Time ◽  
Spot Test ◽  
Test Analysis

This paper describes a method for quantitative spot test analysis of hydrochlorothiazide using diffuse reflectance spectroscopy. The reflectance measurements were performed analyzing the colored compound (l = 585 nm) produced from the reaction between hydrochlorothiazide and p-dimethylaminocinnamaldehyde (PDAC) in acid medium. This reaction occurred on filter paper after heating to 80ºC for 8 minutes. Factorial designs allowed varying multiple reaction factors simultaneously in order to obtain the best reaction conditions. These factors included heating temperature, heating time, acid volume and PDAC volume. The linearity was studied in the range of 3.36x10-2 to 1.01x10-1 mol L-1 with a correlation coefficient of 0.998. The limit of detection was estimated to be 1.32x10² mol L-1. Commercial samples were analyzed using the proposed method and the results were favorably compared with those of the United States Pharmacopeia method, showing that quantitative spot test analysis by diffuse reflectance could be successfully used to determine hydrochlorothiazide in medicines.

scholarly journals Determination of atenolol in pharmaceutical formulations by diffuse reflectance spectroscopy

2008 ◽  
Vol 33 (4) ◽  
pp. 7-12 ◽  
Author(s):  
M. A. Gotardo ◽  
R. Sequinel ◽  
L. Pezza ◽  
H. R. Pezza
Keyword(s):  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Limit Of Detection ◽  
Pharmaceutical Formulations ◽  
Reflectance Spectroscopy ◽  
Reaction Conditions ◽  
British Pharmacopoeia ◽  
Reflectance Measurements ◽  
Good Agreement

A simple analytical method for quantification of atenolol in pharmaceutical formulations by diffuse reflectance spectroscopy is described. The method is based on the reaction, on the filter paper surface, between the drug and p-chloranil producing a colored compound. The best reaction conditions were obtained with 20 µL of atenolol solution and 20 µL of p-chloranil. All reflectance measurements were carried out at 550 nm and the linear range was from 1.13x10-2 to 7.88x10-2 mol L-1 (r = 0.9992). The limit of detection was 2.80 x 10-3 mol L-1. The proposed method was successfully applied to analysis of different commercial brands of pharmaceutical formulations and the results obtained by the proposed method were in good agreement with those obtained using the British Pharmacopoeia method.

A simple and green analytical method for determination of copper(ii) in whisky and sugarcane spirit by diffuse reflectance spectroscopy

2016 ◽  
Vol 8 (8) ◽  
pp. 1867-1875 ◽  
Author(s):  
João Carlos de Souza ◽  
Helena Redigolo Pezza ◽  
Leonardo Pezza
Keyword(s):  
Analytical Method ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Environmentally Friendly ◽  
Reflectance Spectroscopy ◽  
Spot Test ◽  
Analytical Methodology ◽  
Determination Of Copper

In this paper we propose a new, fast, simple, economical, portable and environmentally friendly analytical methodology for the determination of copper(ii) ions in whisky and sugarcane spirit, using the combination of spot-test and diffuse reflectance spectroscopy.

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