Improved gas chromatographic method and micro-extraction technique for the measurement of nicotine in biological fluids.

A rapid and sensitive method for the measurement of nicotine in plasma, urine, saliva and breast milk is described. An internal standard (quinoline) is added to the samples and these are made alkaline and extracted with diethyl ether. The solvent is evaporated to small bulk and extracted with dilute acid which is then made alkaline. The nicotine is finally extracted into butyl acetate and an aliquot of this extract is injected onto a gas-chromatograph fitted with a nitrogen detector. Quantitation relies on comparison of peak areas and the calibration curve is linear over the concentration range 0.5 to 100 ng ml-1. Nicotine concentrations as low as 0.1 ng ml-1 can be measured. In addition, a micro-method is described which requires only 100 microliter of sample and yields an accurate result in 5 min.