A screening method for the essential oils in hops using solid-phase microextraction

Separation and isolation of organic analytes from environmental matrices such as soils,\ud water, plant, or animal tissue has traditionally involved the use of liquid solvent extractions.\ud Solvent-based extraction methods are often time-consuming, difficult to automate, and use\ud expensive solvents that generate hazardous waste and working conditions. The need for a rapid,\ud reproducible, inexpensive, environmentally-friendly, and non-destructive technique for sample\ud monitoring and quantitation have promoted the development of newer extraction techniques.\ud Conventional techniques for headspace analysis such as purge and trap have been developed to\ud limit solvent use and increase automation, however this method still requires some use of solvents\ud and sample manipulation.\ud Solid-phase microextraction (SPME) is a rapid, relatively inexpensive, and solvent-frce\ud extraction technique. The apparatus consists of a fused silica fiber, coated with a highly\ud absorbent organic phase, attached to a microsyringe for handling convenience (Figure 1). The\ud extraction procedure involves the exposure of the fiber directly into an aqueous sample or to a\ud sample's headspace. Upon equilibrium between the fiber coating and the sample, the fiber is\ud introduced to the heated inlet of the GC, where the analytes are completely desorbed from the\ud fiber coating'