Fluorimetric determination of aluminium in pharmaceuticals according to Ph. Eur. 2.4.17

INTRODUCTION

Fluorimetry/Fluorometry is a method, which uses the measurement of the intensity of the fluorescent light emitted by the substance. Fluorimetry is included in all modern pharmacopoeias, including:

• European Pharmacopoeia (10^th Edition, 2019)
• Ph. Eur. 2.2.21. Fluorimetry
• British Pharmacopoeia (2020 Edition)
• Ph. Br. Vol. IV. Appendix II E. Fluorescence spectrophotometry
• US Pharmacopoeia (USP 43–NF 38, 2019)
• USP General Chapters: <853> Fluorescence spectroscopy
• Japanese Pharmacopoeia (XVII Edition, 2017)
• JP XVII. General tests. 2.22. Fluorometry
• The International Pharmacopoeia (9^th Edition, 2019)
• Ph. Int. 1.9. Fluorescence spectrophotometry
• The State Pharmacopoeia of the Russian Federation (XIV Edition, 2018)
• GPM.1.2.1.1.0006.15. Fluorometry
• EEU Pharmacopoeia (1^st Edition, 2020)
• EEU Pharmacopoeia. GPM 2.1.2.20. Fluorometry

METHOD

Fluorimetry is widely used to determine the aluminium impurity in pharmaceuticals using hydroxyquinoline, for example by Ph. Eur. 2.4.17. The fluorimetric method is based on formation of a complex compound between aluminium ion and hydroxyquinoline and extraction with chloroform followed by measurement of fluorescence intensity of the extract (excitation wavelength 392 nm and emission wavelength 518 nm) using Fluorat-02 analyzer.