An approach to application of mesoporous hybrid as a fiber coating of solid-phase microextraction

MCM-41-typed mesoporous hybrid was investigated as the fiber coating of solid-phase microextraction (SPME) compared with bonded porous silica for the extraction of aromatic compounds in combination with HPLC. It was found that the mesoporous fiber coatings have higher sensitivity and better selectivity of extraction than bonded silica phase (BSP) coating because their larger surface area and smaller mesopores. Especially the extraction efficiency of modified mesoporous fiber coating was about 3-5 times higher than that of BSP. Moreover the values of distribution ratio for toluene and biphenyl is larger than those for p-xylene and anthracene. Desorption can be performed in mobile phase within 5 min. Vigorous stirring and higher temperature can improve the sensitivity of SPME with mesoporous coatings because mass transfer from bulk solution to the mesopores is diffusion controlled in extraction process. The mesoporous fiber coatings lose their extraction selectivity and show rapidly decreasing extraction efficiency by increasing content of methanol in water matrix. Different from general polymeric coatings of SPME. However, the mesoporous coatings show negative effect of ionic strength on extraction. Chemical modification also enhances the hydrothermal stability of mesoporous silica. Custom made SPME fiber with inesoporous hybrid coating still gives good reproducibility after 200 runs. The recovery is 99.86-100.32% and the relative standard deviation is 0.11-1.51% for the determination of studied compounds in spiked water. The limit of detection was in the range 2.00 x 10(-8) to 6.91 x 10(-9) mol L-1. (c) 2005 Elsevier B.V. All rights reserved.