Fast flow-injection fluorimetric determination of amiloride by using a solid sensing zone.

Area of Science:

• Analytical Chemistry
• Spectrofluorimetry
• Flow-Injection Analysis

Background:

• Accurate determination of the diuretic amiloride is crucial for therapeutic monitoring and pharmaceutical quality control.
• Existing analytical methods may require complex sample preparation or derivatization steps.
• Development of rapid, sensitive, and direct detection methods is needed for physiological fluids and pharmaceutical samples.

Purpose of the Study:

• To develop and validate a rapid, simple, flow-through solid-phase spectrofluorimetric system for amiloride determination.
• To enable direct measurement of amiloride's intrinsic fluorescence in serum and pharmaceutical preparations.
• To establish a sensitive and reliable analytical method with minimal sample pretreatment.

Main Methods:

• A monochannel flow-injection analysis system coupled with a spectrofluorimetric detector was employed.
• Amiloride was retained on a cationic exchanger gel (Sephadex SP-C25) in the detection cell.
• Direct measurement of intrinsic fluorescence at excitation/emission wavelengths of 291/419 nm, using peak height as the analytical signal.

Main Results:

• The method achieved concentration ranges of 10-600 µg/L and 4-250 µg/L with sampling rates of 24 h⁻¹ and 30 h⁻¹, respectively.
• Detection limits were as low as 0.92 µg/L and 0.33 µg/L for different sample volumes.
• Excellent precision was demonstrated with relative standard deviations better than 0.65% for independent determinations.

Conclusions:

• The developed solid-phase spectrofluorimetric system provides a rapid, simple, and sensitive method for amiloride quantification.
• The method is effective for analyzing amiloride in spiked biological fluids (serum) and pharmaceutical preparations without prior sample treatment.
• This approach offers a valuable tool for routine analysis in clinical and pharmaceutical settings.