高效液相色谱-串联质谱法测定电子烟烟液及气溶胶中4种烟草特有N-亚硝胺类化合物

Determination of 4 Tobacco-Specific N-Nitrosamines in E-Cigarette Liquid and Aerosol by HPLC-MS/MS

建立了高效液相色谱-串联质谱法(HPLC-MS/MS)测定电子烟烟液及气溶胶中4种烟草特有N-亚硝胺类化合物(TSNAs)[包括N-亚硝基去甲基烟碱(NNN)、N-亚硝基假木贼碱(NAB)、N-亚硝基新烟草碱(NAT)和4-(N-甲基-N-亚硝胺)-1-(3-吡啶基)-丁酮(NNK)]含量的方法。取1 g电子烟烟液,加入0.1 mol·L^(-1)乙酸铵溶液20 mL及4 mg·L^(-1)混合内标溶液50μL,超声萃取30 min后,经0.2μm聚四氟乙烯(PTFE)滤膜过滤后进样。将在最大功率下抽吸20口电子烟释放的气溶胶捕集在一张直径为44 mm剑桥滤片上,用上述提取烟液的方法提取气溶胶中的TSNAs。所得滤液中的目标物用Agilent Eclipse Plus C_(18)RRHD色谱柱在60℃柱温下固定,以不同体积比的0.01 mol·L^(-1)甲酸铵溶液和含0.025%(体积分数)甲酸的乙腈溶液的混合溶液为流动相在0.3 mL·min^(-1)流量下进行梯度洗脱;用配有电喷雾正离子源(ESI~+)的串联质谱仪在多反应监测(MRM)模式下检测,以4种TSNAs的氘代试剂作内标物进行内标法定量。结果显示:4种TSNAs的质量浓度均在0.010~5.0μg·L^(-1)内与其对应的峰面积与内标物峰面积的比值呈线性关系,检出限(3S/N)分别为0.002~0.015 ng·g^(-1)(烟液)和0.001~0.008 ng/20口(气溶胶);日内测定值的相对标准偏差(RSD,n=5)分别为0.78%~1.5%(烟液)和0.96%~2.5%(气溶胶),日间测定值的RSD(n=5)分别为1.3%~2.1%(烟液)和4.9%~6.3%(气溶胶);对实际样品进行3个浓度水平的加标回收试验,回收率分别为90.7%~103%(烟液)和92.0%~108%(气溶胶);方法用于14个实际样品的分析,NNN、NAT、NNK、NAB在烟液中的最大检出量分别为40.57,31.94,11.22,8.33 ng·g^(-1),在气溶胶中的最大检出量分别为6.40,5.03,1.89,1.28 ng/20口。

A method was established for determination of 4 tobacco-specific N-nitrosamines(TSNAs)in e-cigarette liquid and aerosol by HPLC-MS/MS,including NNN,NAB,NAT and NNK.Analytes in 1 g of e-cigarette liquid was extracted by 20 mL of 0.1 mol·L^(-1) ammonium acetate solution containing 50μL of mixed internal standard solution ultrasonically for 30 min and then filtered through a 0.2μm PTFE filter.20 puffs of aerosol realeased at maximum power were collected by a 44 mm diameter Cambridge filter,and the TSNAs in aerosol were extracted by the same method as e-cigarette liquid.The analytes were fixed on an Agilent Eclipse Plus C18 RRHD chromatographic column at 60℃,and mixed solutions of 0.01 mol·L^(-1) ammonium formate solution and acetonitrile solution containing 0.025%(φ)formic acid with the different volume ratios were used as mobile phase for gradient elution at flow rate of 0.3 mL·min-1.A tandem mass spectrometer equipped with ESI+was used for detection under multi-reaction monitoring(MRM)mode.Four deuterated reagents of TSNAs were used as internal standards for quantitative analysis.The results showed that linear relationships between mass concentrations of 4 TSNAs and the ratios of their corresponding peak areas to those of internal standards were kept in the same range of 0.010-5.0μg·L^(-1).Detection limits(3 S/N)were 0.002-0.015 ng·g-1(e-cigarette liquid)and 0.001-0.008 ng/20 puffs(aerosol)respectively,RSDs(n=5)of the determined values for the intra-day were 0.78%-1.5%(e-cigarette liquid)and 0.96%-2.5%(aerosol)respectively,RSDs(n=5)of the determined values for inter-day were 1.3%-2.1%(e-cigarette liquid)and 4.9%-6.3%(aerosol)respectively.The spiked recovery test was made on actual samples at the 3 concentration levels,giving results of recovery in the ranges of 90.7%-103%(e-cigarette liquid)and 92.0%-108%(aerosol)respectively.This method was used to analyze 14 actual samples,with maximum detectable amounts of NNN,NAT,NNK and NAB in e-cigarette liquid of 40.57,31.94,11.22,8.33 ng·g-1 and in aerosol of 6.40,5.03,1.89,1.28 ng/20 puffs.