기체 크로마토그래피/질소-선택적 검출을 이용한 소변 중 니코틴과 코티닌의 동시 분석

다국어 초록 (Multilingual Abstract)

A gas chromatographic method was established for the simultaneous determination of urinary nicotine and cotinine. The analytes in basified urine containing a sufficient amount of Na₂SO₄ were extracted into dichloromethane by vigorous shaking. Into the transferred organic phase was added a small amount of acidified methanol (0.5 N HCl in methanol), followed by concentrating the mixture to dryness using a mild stream of nitrogen gas. The concentrate was reconstituted with methanol and the final solution analyzed using the gas chromatograph equipped with the nitrogen-phosphorus detector. The reproducibility tests showed coefficients of variation less than 11% for both compounds. The percent recovery for both analytes ranged from 88 to 103%. The estimated method detection limits for nicotine and cotinine were 0.60 and 5.1 ng/mL, respectively. Extraction efficiencies for both nicotine and cotinine apparently declined without the addition of Na₂SO₄ into the urine. Moreover, the absence of methanolic HCl in the extract resulted in almost complete evaporation of nicotine and partial loss of cotinine during the concentration process, indicating that the formation of nicotine-HCl and cotinine-HCl species is prerequisite to the suppression of the loss of both compounds.