Abstract
Abstract The development of faster, simpler and economic sample-preparation techniques is an important issue in chemical analysis. In this work, four analytical methods base liquid-phase microextraction (LPME) and dispersive liquid-liquid microextraction (DLLME) were described. The developed methods have been applied to the analysis of trace pollutants and abuse drugs in different sample matrices such as lake, river or human urine. Liquid phase microextraction method, which included hollow fiber liquid-phase microextraction (HF-LPME), single-drop microextraction (SDME), were investigated in the chapter one, chapter two, and chapter four. This methodology provided to be extremely simple, low cost and virtually solvent-free sample-preparation technique, which provided a high degree of selectivity and enrichment. The results show that these sample-preparation coupled with GC-ECD or GC-MS could determinate the trace organic pollutants in the ppb level. The DLLME developed by Yaghoub Assadi in 2006 has emerged as a virtually time-free alternative for extraction time to conventional liquid-liquid extraction and solid-phase extraction even SPME and LPME procedures. It involves the partition of analytes between the aqueous and extremely small organic drop and the surface area between the aqueous and organic drop is enhanced dramatically. Thus the extraction time is reduced effectively. Second chapter describes the development of DLLME technique where extraction and derivatization were carried out in one-step. In this work, the derivatizating reagent was added into extraction solvent so that the analytes can be derivatized as the partition of analytes into extraction solvent was carried out. This technique was applied to the analysis of amphetamine and methylenedioxyamphetamine in urine sample from abusers.