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 R 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).