The Study On The Method For Determining Cotinine And Nicotine In Urine With SPME-GC/MS

[Objectives]Throuth researching on the conditions for Solid Phase Micro-extraction(SPME) and the parameters of GC/MS,to establish the method for determining cotinine and nicotine in human urine with SPME-GC/MS;to investigate the stability of cotinine and nicotine in human urine,determine the acceptable storage temperature and time of human urine;to determine the actual human urine samples with the established SPME-GC/MS method,to verify the feasibility of the established method,preliminary understand the urine cotinine and nicotine levels of population,so as to provide detection tools and experimental data for related research later.[Methods]Carried out the pretreatment of nicotine and cotinine in human urine with SPME,and determined them with GC/MS,to establish the method for determining cotinine and nicotine in human urine with SPME-GC/MS;Studied and optimized the parameters of GC/MS and conditions influencing SPME,such as the extracting fiber,extracting model,pH of matrix, salt adding in to urine,extracting tempreture,extracting time,dedorption tempreture and time,to get the optimal parameters and experimental conditions;compared the storage temperatures and storage times of urine samples,investigaged the stablitiy of three kinds of urine samples with different concentrations;determined the urine cotinine and nicotine concentrations of passive smokers,active smokers and non-smokers with the established method. [Results](1) Proposed the optimal conditions for SPME of nicotine and cotinine in human urine, determine the optimal parameters for GC/MS,and established the method for determining cotinine and nicotine in human urine with SPME-GC/MS.The linear range of this method is 10-1000ng/mL both for cotine and nicotine,the Limit of Detection(LOD) is 0.74ng/mL and 1.64ng/mL for cotinine and nicotine respectively,the RSD is between 6.02 and 12.54%for cotinine and between 4.52 and 11.48%for nicotine, the mean recoveries 4.52-11.48%for cotinine and 75.72-95.32%for nicotine are achieved.(2) The experiment on the stability of cotinine and nicotine indicates that the urine sample is not suitable for storage at room temperature(18±4℃),the urine samples would deteriorate in 1 day at the room temperature,but could be stored 1 week at 4℃,and were stable nearly 1 month at-20℃.(3) This study determined 56 healthy adults urine sample with the established method.Among them,12 were passive smoker,with the range N.D.-445.76ng/mL for cotinine and N.D.-321.81ng/mL for nicotine;25 were active smokers,with the range 315.10-9746.60ng/mL for cotinine and 151.70-9109.70 ng/mL for nicotine;19 were non-smokers,with the range N.D.-84.63 ng/mL for cotine and N.D.-54.64 ng/mL for nicotine.[Conclusions]The SPME-GC/MS method for determining cotinine and nicotine in human urine established by this study is easy to operate,quick to analysis,accurate to quantify,and verified by the investigated human urine samples,the characteristics of the method is in line with the requirements of the analysis of actual urine samples;Study the stability of cotinine and nicotine in human urine with the SPME-GC/MS method,pointed out the acceptable temperature condition and time for storage,provide the scientific basis for the related analytic study of urine; determined cotinine and nicotine in some human urine samples with the established method, acquired the approximative results to native and foreign related studies,provide detection tools and experimental data for assessment of human exposure to tobaocco smoke.The SPME-GC/MS method established by this study is practicable,meets the research objectives of study design.