Gas chromatographic determination of zopiclone in plasma after solid-phase extraction

A gas chromatographic technique for determining zopiclone based on a solid-phase extraction procedure with C18 cartridge for sample clean-up is presented. Quantification can be achieved with 1 ml of plasma. The method uses prazepam as internal standard. Zopiclone is separated on a 5% phenyl methyl silicone analytical column and detected with an electron-capture detector, which consequently allows a limit of quantitation of 2 micrograms/l. It is thus simple, rapid, sensitive and linear over the range 5-2000 micrograms/l.