Self-assembly of mercaptoundecanol on cedar-like Au nanoparticle coated stainless steel fiber for selective solid-phase microextraction

Abstract

A novel organic–inorganic composite coated fiber was developed by direct chemical deposition of Au nanoparticles (AuNPs) followed by self-assembly of mercaptoundecanol using an etched stainless steel (ESS) wire as a supporting substrate for selective solid-phase microextraction (SPME). The ESS wire offered a very large contact surface for the subsequent growth of AuNPs in chloroauric acid solution. As a result, a uniform AuNP coating with a cedar-like structure was formed on the ESS wire and used as an alternative substrate for self-assembly of mercaptoundecanol (HS-C₁₁-OH) via Au–S bonding. The mercaptoundecanol modified AuNP coated ESS (ESS/AuNPs-S-C₁₁-OH) fiber was then assessed for SPME of ultraviolet filters, phthalic acid esters and polycyclic aromatic hydrocarbons (PAHs) coupled to high-performance liquid chromatography with UV detection. This fiber exhibits high extraction capability and better selectivity for PAHs. Moreover, main parameters affecting extraction were investigated and optimized. Under the optimized conditions, the developed method showed good linearity between 0.05 and 300 μg L⁻¹ with corresponding coefficients in the range of 0.9973–0.9992. The limits of detection ranged from 0.010 to 0.044 μg L⁻¹. The relative standard deviation for the fiber-to-fiber reproducibility of five fabricated fibers was less than 6.52%. The developed method was successfully applied to the preconcentration and determination of PAHs from environmental water samples. Furthermore, the preparation of the ESS/AuNP-S-C₁₁-OH fiber can be performed in a highly reproducible manner. This fabricated fiber exhibits high stability and withstands at least 200 extraction and desorption replicates.