ABSTRACT
Sample preparation is the step between sampling and analysis. The analytes must be separated from the sample because most environmental samples cannot be directly introduced into an instrument. For extraction of organic analytes from liquids sample, liquid–liquid extraction(LLE) and solid-phase extraction (SPE) can be employed. Liquid–liquid extraction is a popular method for extracting organic pollutants from liquid matrices, especially water. Continuous LLE is an alternative to multi-step batch LLE. Solid-phase extraction (SPE) is also known as liquid–solid extraction. A SPE cartridge is made by packing few milligrams of an adsorbent in a tube. SPE has several advantages over LLE. This technique is rapid and does not involve extensive solvent use and consequently generates less waste. Solid-phase microextraction is a recently developed system which uses a fused silica fiber, coated with a nonvolatile organic liquid or polymer to sorb organic vapors from aqueous or vapor samples.
