Yttria-based sol–gel coating for capillary microextraction online coupled to high-performance liquid chromatography

This work about the development of yttria-based polymeric coating using [bis(hydroxyethyl) amine] terminated polydimethylsiloxanes and yttrium trimethoxyethoxide inside the capillary. The coated capillary was utilized for online capillary microextraction and high-performance liquid chromatography analysis. The prepared coating material was characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectrometry, and thermogravimetric analysis. The coated capillary with polymer presented better extraction efficiency compared with the pure yttria-based coated capillary with applicability in extreme pH environments (pH 0–pH 14). Excellent extraction towards polyaromatic hydrocarbons, aldehydes, ketones, alcohols, phenols, and amides was observed with limit of detection ranging from 0.18 to 7.35 ng/mL (S/N = 3) and reproducibility in between 0.6 and 6.8% (n = 3). Capillary-to-capillary extraction analysis has presented reproducibility between 4.1 and 9.9%. The analysis provided linear response for seven selected phenols in the range of 5–200 ng/mL with R² values between 0.9971 and 0.9998. The inter-day, intra-day, and capillary-to-capillary reproducibility for phenols was also <10%. Real sample analysis by spiking 5, 50, and 200 ng/mL of phenols in wastewater and pool-water produced recovery between 84.7 and 94.3% and reproducibility within 7.6% (n = 3).