Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (23): 2440-2444.DOI: 10.6023/A12080544 Previous Articles     Next Articles



艾佑宏a,b, 赵发琼a, 曾百肇a   

  1. a 生物医学分析化学教育部重点实验室 武汉大学化学与分子科学学院 武汉 430072;
    b 湖北大学化学化工学院 武汉 430062
  • 投稿日期:2012-08-11 发布日期:2012-11-01
  • 通讯作者: 曾百肇
  • 基金资助:
    项目受国家自然科学基金(Nos. 20975078, 21275112)资助.

Electrochemical Fabrication of Hydrophobic Ionic Liquid–Polyaniline Composite Coating for Solid-Phase Microextraction and Its Application in the GC Determination of Phenolic Compounds

Ai Youhonga,b, Zhao Faqionga, Zeng Baizhaoa   

  1. a Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China;
    c College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062, China
  • Received:2012-08-11 Published:2012-11-01
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Nos. 20975078, 21275112).

A stainless steel wire was immersed in a hydrophobic ionic liquid (IL, i.e. 1-octyl-3-methylimidazolium hexafluorophosphate), then was heated under an infrared lighter to make the viscous IL form an even and reproducible film on the steel wire. After that polyaniline (PANI) was electrodeposited on it from an aqueous solution containing 0.1 mol·L-1 aniline and 1.0 mol·L-1 HNO3 through cyclic voltammetry. The potential range was -0.2~1.2 V (vs. saturated calomel electrode, SCE), the scan rate was 50 mV·s-1 and the cyclic potential scan was repeated for 70 times. For the electrodeposition a conventional three-electrode system was adopted, including the IL coated stainless steel wire as working electrode, a platinum wire as counter electrode and a saturated calomel electrode as reference electrode. The resulting PANI-IL composite coating was rinsed with methanol and distilled water. Following this, it was conditioned in a electric furnace with nitrogen atmosphere at 90℃ for 30 min, at 250℃ for 150 min. When the obtained fiber was cool, it was fixed on a home-made device for solid-phase microextraction (SPME) with epoxy resin. The coating showed netlike structure, with smaller hole and larger surface area than that of PANI. Taking several phenolic derivatives (i.e. 2-chlorophenol, 2-methylphenol, 2,6-dimethylphenol, 2,4-dimethylphenol and 3-methylphenol) as models, the analytical performance of the fiber was investigated. Under the optimized conditions (i.e. extraction temperature: 60℃; extraction time: 40 min; stirring rate: 600 r/min; NaCl concentration: 0.35 g·mL-1; desorption time: 3 min; desorption temperature: 250℃), when the phenols were determined by GC after headspace solid-phase microextraction with the fiber, the linear ranges were 0.048~400 μg·L-1 with correlation coefficients above 0.99; the detection limits were 6.1~98 ng·L-1 (S/N=3). The relative standard deviations (RSD) of chromatographic peak area were smaller than 5.5% for five successive measurements with single fiber, and the fiber to fiber RSD was 3.7%~12% for different phenols (n=3). The fiber also presented good stability and its extraction efficiency kept almost unchanged after being used for about 150 times; when the temperature was up to 300℃ it did not decompose. In comparison with PANI fiber, the PANI-IL fiber showed higher extraction capability. The PANI-IL fiber was successfully applied to the determination of phenols in waste water from a chemical factory.

Key words: electrochemical polymerization, solid-phase microextraction, phenols, ionic liquid, polyaniline