Enzymatic single drop microextraction
Single drop microextraction (SDME), which was described in the middle 90´s, is an effective extraction technique which comprises isolation and preconcentration in one step, allowing the direct injection of the extracts in different analytical instruments. In SDME, a small volume of extractant is aspirated in a microsyringe which is introduced in the extraction vessel where the sample is located. A small drop of extractant, in the range of 1-5 µL, is finally exposed to the sample (direct immersion mode) or to its headspace (headspace mode) in order to extract the target analytes. After the extraction, the drop is retracted into the microsyringe which will be finally transferred to the appropriate analytical instrument. In the usual situation, the extractant is an organic solvent with suitable properties. In this way, the solvent should present a high affinity towards the analytes in order to isolate them from the sample matrix. Moreover, the organic solvent should present a low vo...