The Study On The Determination Of Nicotine And Cotinine In Biological Samples By Gas Chromatography-mass Spectrometry

ObjectiveThe purpose of this study was to explore pre-treatment methods that were simple, fast, low cost, easy to extracted the nicotine and cotinine in biological samples, and determined them by gas chromatography - mass spectrometry. To provide effective technical supports for the tobacco exposure assessment in tobacco control.MethodsUsed chloroform to extract the nicotine and cotinine in human urine, hair, and saliva, and determined them by gas chromatography - mass spectrometry(GC/MS); Studied and optimized the conditions influencing liquid-liquid extracted(LLE), such as the organic solvents selection, NaOH concentration of urine and saliva alkalization, NaOH concentration of hair digestion, hair digestion time and the oscillation mode in extraction and the parameters of GC/MS; to establish the method for determining nicotine and cotinine in human urine, hair and saliva by LLE-GC/MS.Results1.The experiments choose chloroform as extraction solvent and vortex mixed 75s and centrifuged 5min to extract; Alkalized urine and saliva with 2mol/L of NaOH added 3ml 1.5mol/L of NaOH in 100mg hair and digested hair in ultrasound for 30min and in water bath for 3h; The initial column temperature of 140℃, third-order temperature program, selected ion scan and diphenylamine as the internal standard for instrument parameters selection. 2. The detection limits of the method were 0.006μg/ml,0.014μg/ml, for nicotine and cotinine respectively. The limits of quantification were 0.020μg/ml,0.048μg/ml respectively. The line ranges of the method were 0.022-4μ./ml and 0.048-4μg/ml for nicotine and cotinine respectively. The precisions of the method were 1.98%-2.69% and 4.70%-6.65% for nicotine and cotinine in urine,0.87%-2.89% for nicotine in hair, 4.89%-4.54% for cotinine in saliva. The recoveries of the spiked samples ranged from 82.40%-106.48% and 81.80%-99.55% for nicotine and cotinine respectively in urine, 85.37%-103.91% for nicotine in hair,80.50%-93.00%for cotinine in saliva.3. This urine samples of 90 healthy adults and the hair samples of 45 healthy adults were determined by the established method. The average concentrations of human urine were 0.13μg/mgcr and 0.20μg/mgcr for nicotine and cotinine; The average concentration of human hair was 6.75μg/g for nicotine.ConclusionThe study built methods of determining nicotine and cotinine in human urine, hair, and saliva by gas chromatography-mass spectrometry.The methods were easy to operate, quick to analyze, accurate to quantify, low cost to apply. Used for the determination of real samples with satisfactory results. It can provide effective technical supports for the tobacco exposure assessment.