Abstract

Stability-indicating analytical methods are essential for accurately monitoring pharmaceutical residues and their transformation products in complex matrices, particularly when photo-degradation may compromise analyte integrity. Ultra-performance liquid chromatography (UPLC) was employed to effectively separate and quantify hydrochlorothiazide (HCTZ) alongside its three primary photo-degradation products in river water samples. The linearity range for quantification was established between 0.1 and 10 µg/mL. To properly prepare samples for analysis, the solid-phase extraction (SPE) method has been developed and is widely utilized. Even when up to 90% of the main photodegradable products are present, the suggested approach can still assess HCTZ. After a thorough validation process that followed the parameters set by the International Council for Harmonisation (ICH-Q2B), river water samples were treated using SPE. This study presents a novel UPLC method for detecting the target pharmaceutical alongside its primary photo-degradates in river water. The presented method demonstrates sufficient sensitivity to effectively monitor the level of environmental contamination resulting from the pharmaceutical under investigation.

Key words: pollution monitoring; river water; environmental analysis; environmental sustainability; water pollution