Electrodeposition of gold nanoparticles onto an etched stainless steel wire followed by a self-assembled monolayer of octanedithiol as a fiber coating for selective solid-phase microextraction

• A novel C8–S–AuNPs coating was achieved through electrodeposition and SAM process.
• A unique floccular structure with extremely larger surface area was obtained.
• The fiber has high extraction capability and better selectivity for UV filters.
• The fiber has high stability and long lifetime.
• The SPME–HPLC method was applied to target UV filters in environmental water samples.

In the present study, a novel approach for rapid electrodeposition on an etched stainless steel (SS) wire followed by self-assembled monolayer (SAM) was proposed for the fabrication of solid-phase microextraction (SPME) fiber. The etched SS wire offers a rough surface structure for subsequent electrochemical deposition of gold nanoparticles (AuNPs). As a result, uniform AuNPs coating was tightly attached to the etched SS wire substrate. After SAM of 1,8-octanedithiol onto AuNPs coating via Au-S bonding, a unique floccular structure with extremely large surface area was obtained for the fabricated fiber. The mercaptooctyl groups modified AuNPs coated etched SS fiber (C8–S–AuNPs/SS) was then assessed for SPME of phthalate esters (PAEs), polychlorinated biphenyls (PCBs), chlorophenols (CPs), ultraviolet (UV) filters, polycyclic aromatic hydrocarbons (PAHs) and substituted anilines coupled to high-performance liquid chromatography with UV detection. This fiber exhibits higher extraction capability and better selectivity for some PCBs, CPs, UV filters and PAHs. Extraction conditions were investigated and optimized for SPME performance of UV filters. Under the optimized conditions, the developed method showed good linearity between 0.10 and 400 μg L−1 with corresponding coefficients in the range of 0.9989–0.9998. The limits of detection ranged from 0.025 to 0.056 μg L−1. The relative standard deviation for fiber-to-fiber reproducibility of five fabricated fibers was less than 9.4%. The developed method was successfully applied to the preconcentration and determination of trace UV filters from environmental water samples. Furthermore the fabrication of the C8–S–AuNPs/SS fiber can be performed in a highly reproducible manner. This fabricated fiber exhibits good stability and long lifetime, and could be a potential alternative for the conventional fused silica fiber.