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Updated: Jun 17, 2026

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Published on: October 25, 2021
Quantitative spot-test analysis of metformin in pharmaceutical preparations using ultraviolet-visible diffuse
Matthieu Tubino1, Luís Francisco Bianchessi, Marta M D C Vila
1Institute of Chemistry, University of Campinas, P. O. Box 6154, BR-13083-970 Campinas, SP, Brazil. tubino@iqm.unicamp.br
Abstract:
A quantitative spot-test for the determination of metformin in pharmaceutical preparations using diffuse UV-visible reflectance is reported. The procedure is quite simple, involving in the formation of a metformin-nickel(II) complex on a glass filter membrane with a later measurement of the reflectance in the spectrophotometer using an integration sphere. The analytical results obtained with commercial products were statistically compared with those resulting from a method recommended by JP and by USP, where complete agreement was observed. The average RSD is 2.5% and the detection (0.009 mol L(-1)) and the quantitation (0.03 mol L(-1)) limits are quite adequate for pharmaceutical analysis.
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