A fiber-in-tube solid-phase microextraction device based on a gold-functionalized stainless-steel wire and tube was developed and characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. In combination with high-performance liquid chromatography, it was evaluated using six polycyclic aromatic hydrocarbons as model analytes. Important parameters including sampling rate, sample volume, organic solvent content and desorption time were investigated. Under optimized conditions, an online analysis method was established. The linearity was in the range of 0.15–50 μg/L with correlation coefficients ranging from 0.9989 to 0.9999, and limits of detection ranged from 0.05 to 0.1 μg/L. The method was applied to determine model analytes in mosquito-repellent incense ash and river water samples, with recoveries in the range of 85–120%.

Stir bar sorptive extraction is an environmentally friendly microextraction technique based on a stir bar with various sorbents. A commercial stirrer is a good support, but it has not been used in stir bar sorptive extraction due to difficult modification. A stirrer was modified with carbon nanoparticles by a simple carbon deposition process in flame and characterized by scanning electron microscopy and energy-dispersive X-ray spectrometry. A three-dimensional porous coating was formed with carbon nanoparticles. In combination with high-performance liquid chromatography, the stir bar was evaluated using five polycyclic aromatic hydrocarbons as model analytes. Conditions including extraction time and temperature, ionic strength, and desorption solvent were investigated by a factor-by-factor optimization method. The established method exhibited good linearity (0.01–10 μg/L) and low limits of quantification (0.01 μg/L). It was applied to detect model analytes in environmental water samples. No analyte was detected in river water, and five analytes were quantified in rain water. The recoveries of five analytes in two samples with spiked at 2 μg/L were in the range of 92.2–106% and 93.4–108%, respectively. The results indicated that the carbon nanoparticle-coated stirrer was an efficient stir bar for extraction analysis of some polycyclic aromatic hydrocarbons.

A novel nanostructured copper-based solid-phase microextraction fiber was developed and applied for determining the two most common types of phthalate environmental estrogens (dibutyl phthalate and diethylhexyl phthalate) in aqueous samples, coupled to gas chromatography with flame ionization detection. The copper film was coated onto a stainless-steel wire via an electroless plating process, which involved a surface activation process to improve the surface properties of the fiber. Several parameters affecting extraction efficiency such as extraction time, extraction temperature, ionic strength, desorption temperature, and desorption time were optimized by a factor-by-factor procedure to obtain the highest extraction efficiency. The as-established method showed wide linear ranges (0.05–250 μg/L). Precision of single fiber repeatability was <7.0%, and fiber-to-fiber repeatability was <10%. Limits of detection were 0.01 μg/L. The proposed method exhibited better or comparable extraction performance compared with commercial and other lab-made fibers, and excellent thermal stability and durability. The proposed method was applied successfully for the determination of model analytes in plastic soaking water.