Electrochemical Preparation of Polypyrrole-Ionic Liquid Coating for Solid Phase Microextraction and Its Application in Gas Chromatographic Determination of Benzene Derivatives
A novel polypyrrole-ionic liquid(PPY-IL) film coated steel wire was prepared by electrodeposition in 0.1 mol/L pyrrole+0.1 mol/L p-methyl benzene sulfonate acid+4 g/L 1-butyl-3-methylimidazolium tetrafluoroborate aqueous solution.The PPY-IL coating showed cauliflower structure,with smaller particle size than that of polypyrrole.Taking five benzene derivatives as models,the analytical performance of the resulting fiber was explored.Under the optimized conditions(i.e.extraction temperature:50 ℃;extraction time:40 min;stirring rate:600 r/min;NaCl concentration:0.2 g/mL),when the benzene derivatives were determined by GC after headspace solid-phase microextraction with the PPY-IL fiber,the linear ranges were 0.6-800 μg/L with correlation coefficients above 0.99.The relative standard deviations(RSD) of chromatographic peak areas were smaller than 4.5% for five successive extraction with single fiber,and the RSDs for fiber-to-fiber were 4.5-12.4%(n=5) for different benzene derivatives.The fiber also presented good stability and it still had high extraction efficiency after being used for about 150 times;when the temperature was up to 290 ℃ it did not decompose.In comparison with PPY and polydimethylsiloxane fibers,the PPY-IL fiber showed higher extraction capability and durability.