Novel unbreakable solid‐phase microextraction fiber by electrodeposition of silica sol–gel on gold

Abstract

A new technique for preparation of an unbreakable solid-phase microextraction (SPME) fiber, using sol-gel technology is developed. Primarily, an ultrathin two-dimensional intermediate film was prepared by hydrolysis of 3-(trimethoxysilyl)-1-propanthiol self-assembled monolayer grafted onto gold, then a stationary phase by electrodeposition of 3-(trimethoxysilyl)propylmethacrylate as a precursor, tetramethyl orthosilicate and polyethylene glycol as a coating polymer was produced. The scanning electron microscopy images revealed that the new fiber exhibits a rather porous and homogenous surface. The thermal stability of the fabricated fiber was investigated by thermogravimetric analysis. The applicability of the prepared fiber coating in conjunction with gas chromatography-mass spectrometry was examined by SPME of polycyclic aromatic hydrocarbons, as model analytes, from aquatic media. An extraction time of 20 min at 50 °C gave maximum peak areas when NaCl, 15% was added to the aqueous samples. Limits of detection were in the range of 0.01-0.02 ng/mL and relative standard deviation values were in the range of 4-16% at 1 ng/mL. The developed method was successfully applied for the analysis of real water samples while the relative recovery percentage was in the range of 102-118%.

A novel strategy to increase performance of solid‐phase microextraction fibers: Electrodeposition of sol‐gel films on highly porous substrate

“…It is worth noticing that RSD and LDR of PAHs obtained by this fiber are comparable with those of the commercial fibers. The values were even lower for the LODs in comparison with the commercial fibers and previously reported fiber by the similar technique . The RSDs for each fiber and fiber to fiber of water samples spiked at 1 ng/mL were ≤9 and ≤16%, respectively, which indicate that the proposed method had good repeatability and reproducibility.…”

“…Silicate films can be deposited on any conducting surface, but the sol‐gel film flakes off after drying. To solve this problem, an intermediate layer that could bind the metal surface in one hand and the sol‐gel film in the other hand was used . In a diluted (10 −2 –10 −7 M) solution of the 3MPTS, sulfur atoms can bind (self‐assembled) on the transition metals surface , and a SAM can be formed.…”

“…Figure shows the performance comparison of same coating that is electrodeposited on Au wire using +1.2 V versus Ag/AgCl reference electrode , and electrodeposited on porous Cu/Cu using negative potential (−0.9 V versus Ag/AgCl). As can be seen, the performance of fiber prepared on porous Cu/Cu wire is relatively higher than same coating on Au wire.…”

“…They used a gold or indium tin oxide electrode placed in a sol prepared from methyltrimethoxysilane. Bagheri et al recently used positive potentials (+1.2 V versus Ag/AgCl reference electrode) to electrodeposit sol‐gel film on gold wire to extract polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions .…”

Solid‐phase microextraction of methadone in urine samples by electrochemically co‐deposited sol–gel/Cu nanocomposite fiber

“…Despite the above‐mentioned advantages, sol–gel has had a limited application because of the fragility of the silica fiber used as the support. Recently, some researchers applied unbreakable sol–gel coating on metals, including stainless steel (Es‐haghi, Baghernejad, & Bagheri, ), gold (Bagheri, Sistani, & Ayazi, ), titanium (Jia, Xu, Wang, Wang, & Liu, ) and Cu (Azar, Tehrani, Mohammadiazar, & Husain, ) wires.…”