Thin-film microextraction

Rodriguez-Lafuente, A., Mirnaghi, F.S., and Pawliszyn, J. 2013. Determination of cocaine and methadone in urine samples by thin-film solid-phase microextraction and direct analysis in real time (DART) coupled with tandem mass spectrometry. Anal. Bioanal. Chem., 405 9723-9727. 

Solid-phase microextractions also have been developed. In one approach, a fused silica fiber is placed inside a syringe needle. The fiber, which is coated with a thin organic film, such as poly(dimethyl siloxane), is lowered into the sample by depressing a plunger and exposed to the sample for a predetermined time. The fiber is then withdrawn into the needle and transferred to a gas chromatograph for analysis. 

Solid-phase microextraction (SPME) SPME consists in the adsorption of the target compounds on a thin polymeric film deposed on the surface of a capillary fiber. The mass transfer can be achieved from liquid media in direct contact with the extracting coated fiber as well as from gaseous environments. Volatile or semivolatile herbicides existing in solid samples can be easily transferred in the gas phase on heating in closed vials, followed by trapping of the resulting vapors in the coated fiber (procedure is known as Headspace HD/SPME). 

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