Headspace extraction of alcohols into a single drop

The possibility of applying headspace microextraction into a single drop fo r the determination of alcohols in aqueous solutions is demonstrated. A dro p of ethylene glycol containing butan-2-one as an internal standard is used for extraction. The analytes are extracted by suspending a 1 mul extractin g drop directly from the tip or a microsyringe fixed above an extraction vi al with a septum such that the needle passes through the septum and the nee dle tip appears above the surface of the solution. After the extraction is finished the drop is retracted back into the needle and injected directly i nto a GC column. Optimization of experimental conditions (sampling time, sa mpling temperature, stirring rate and ionic strength of the solution) with respect to the extraction efficiency were investigated and the linear range and the precision were examined. This headspace single drop microextractio n method was applied to the analysis of beer.