title: Magnetism-Enhanced Monolith-Based In-Tube Solid Phase Microextraction.
abstract: Monolith-based in-tube solid phase microextraction (MB/IT-SPME) has received wide attention because of miniaturization, automation, expected loading capacity, and environmental friendliness. However, the unsatisfactory extraction efficiency becomes the main disadvantage of MB/IT-SPME. To overcome this circumstance, magnetism-enhanced MB/IT-SPME (ME-MB/IT-SPME) was developed in the present work, taking advantage of magnetic microfluidic principles. First, modified Fe3O4 nanoparticles were mixed with polymerization solution and in situ polymerized in the capillary to obtain a magnetic monolith extraction phase. After that, the monolithic capillary column was placed inside a magnetic coil that allowed the exertion of a variable magnetic field. The effects of intensity of magnetic field, adsorption and desorption flow rate, volume of sample, and desorption solvent on the performance of ME-MB/IT-SPME were investigated in detail. The analysis of six steroid hormones in water samples by the combination of ME-MB/IT-SPME with high-performance liquid chromatography with diode array detection was selected as a paradigm for the practical evaluation of ME-MB/IT-SPME. The application of a controlled magnetic field resulted in an obvious increase of extraction efficiencies of the target analytes between 70% and 100%. The present work demonstrated that application of different magnetic forces in adsorption and desorption steps can effectively enhance extraction efficiency of MB/IT-SPME systems.
authors.affiliation: State Key Laboratory of Marine Environmental Science, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment and Ecology, Xiamen University , P.O. Box 1009, Xiamen, Fujian 361005, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Mei
authors.affiliation: State Key Laboratory of Marine Environmental Science, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment and Ecology, Xiamen University , P.O. Box 1009, Xiamen, Fujian 361005, China.
authors.forename: Xiaojia
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Materials Science and Engineering, College of Materials, Xiamen University , Xiamen, Fujian 361005, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Marine Environmental Science, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment and Ecology, Xiamen University , P.O. Box 1009, Xiamen, Fujian 361005, China.
authors.forename: Dongxin
authors.initials: D
authors.lastname: Yuan