Akademik Veri Yönetim Sistemi
XXII European Conference on Analytical Chemistry, Barcelona, İspanya, 31 Ağustos - 04 Eylül 2025, ss.141, (Özet Bildiri)
Pharmaceutical residues in environmental waters continue to raise significant public and ecological concerns.
Angiotensin receptor blockers (ARBs) are increasingly present in environmental waters due to massive human
consumption, inadequate metabolism, and ineffective removal via wastewater treatment plants [1]. Due to their
persistence, toxicity, and tendency toward bioaccumulation, trace-level detection of ARBs is crucial for environmental
safety and public health. Nonetheless, efficient sample clean-up/preconcentration techniques are needed to
determine low environmental concentrations of ARBs in complex matrices.
Dispersive micro solid-phase extraction (DMSPE) is a widely used technique in environmental analysis due to its
simplicity, rapidity, and high preconcentration efficiency for trace-level contaminants [2]. In DMSPE, layered double
hydroxides (LDHs) can be employed as effective sorbents thanks to their high surface area, tunable composition,
and ion-exchange capacity [3]. LDHs are two-dimensional nanostructured materials composed of positively charged
metal hydroxide layers with intercalated anions and water molecules, enabling strong interactions with target
analytes. Lab-In-Syringe (LIS) is an analytical automation platform that integrates batch and flow techniques within
a computer-controlled syringe pump, allowing precise reagent handling, in-syringe mixing via magnetic stirring, and
coupling to instrumental systems such as HPLC for fully automated sample preparation and analysis [4].
In this work, a novel LIS-DMSPE method was developed to determine three ARBs in water samples. The approach
was based on the in situ synthesis of Ni/Fe-LDHs within the void of an automatic syringe pump through controlled
pH adjustment following the aspiration of precursor solutions. This enabled the rapid formation of the adsorbent
and eliminated the need for pre-synthesized or magnetized sorbents. Enhanced sedimentation speed, achieved by
increasing ionic strength with NaNO3, allowed isolating the sedimented sorbent from the sample matrix without
centrifugation and filtration.
After washing procedures, the LDHs were dissolved using a formic acid:methanol mixture, followed by transfer of
the extract to the online coupled HPLC-DAD system. The low organic solvent content of the extract allowed largevolume
injection (200 μL), which enhanced sensitivity. Systematic optimization of critical method parameters such
as pH, amounts of precursors and buffers, ionic strength, stirring speed, and elution conditions was carried out.
Among seven LDHs tested, Ni/Fe-based LDH displayed the optimal balance between extraction efficiency, rapid
sedimentation, and easy dissolution. The method provided acceptable linearity (5–100 μg L⁻¹), recoveries (62.0–
88.7%), as well as enrichment factors (13.3–25.8). The limit of detection values were between 1–1.5 μg L⁻¹ with
precision (RSD < 3.5%) and accuracy (94.1–104.8%) obtained by standard addition in real water samples. To our
knowledge, this is the first report on a LIS-DMSPE method that does not require pre-synthesis or magnetization of
the sorbent for extraction and uses accelerated sedimentation for adsorbent isolation.