吹扫/捕集-热脱附气质联用法对荷叶挥发油成分的对比分析

采用同时蒸馏萃取提取得到荷叶挥发油, 通过吹扫/捕集-热脱附法(P&T-TD)对上述提取物中挥发性成分进行富集, 以气质联用(GC/MS)进行定性检测, 同时与直接进样GC/MS法分析的成分进行比较. 两种方法成功分离分析出有机酸、酯、醛、醇、酚、烷烃、芳香烃、烯烃以及含氮、硫、氧杂原子的化合物等共计84种成分, 其中P&T-TD GC/MS鉴定出63种有机化合物, GC/MS鉴定出41种有机化合物, 有20种成分共同检出. 对比分析表明: P&T-TD GC/MS的吹扫/捕集-热脱附过程能富集各种组分, 相比GC/MS分析, 可以鉴定出微量成分及更多挥发性和半挥发性成分, 在精油等挥发性成分的分析检测中使用优势明显.     

基于HPLC-TOF/MS与HPLC-MS/MS的养心氏片主要成分研究

采用高效液相色谱-高分辨飞行时间质谱联用技术(HPLC-TOF/MS),建立了快速鉴定养心氏片化学成分的定性方法,并利用高效液相色谱-串联三重四极杆质谱(HPLC-MS/MS)对养心氏片的主要成分进行定量分析。HPLC-TOF/MS法以ZORBAX Eclipse Plus C18(100 mm×3.0 mm,1.8μm)为色谱柱,乙腈-0.1%甲酸为流动相,梯度洗脱,流速为0.2 mL·min~(-1),柱温30℃,质谱采用正、负离子扫描,可推断鉴定养心氏片中的30种成分。HPLC-MS/MS法采用Waters XBridgeBEH C18(150 mm×4.6 mm,2.5μm)为色谱柱,乙腈-0.1%甲酸为流动相,梯度洗脱,流速0.4 mL·min~(-1),柱温30℃,Scheduled MRM正负离子切换监测模式定量分析。对养心氏片中16种主要成分进行HPLC-MS/MS分析,16种成分的质量浓度与峰面积呈良好线性,相关系数r≥0.997,检出限为0.039 1~78.1μg/L,定量下限为0.156~312μg/L,平均加标回收率为96.8%~103.8%,相对标准偏差(RSD)为1.0%~3.5%。结果表明,该方法操作简便、结果准确、重复性好,可用于养心氏片中多组分的同时定性和定量分析,为养心氏产品的质量控制、药理研究和应用奠定了基础。     

2,4,6-三氯酚纯品原料纯度定值方法研究

对用于溶液标准物质制备的纯品原料2,4,6-三氯酚纯度定值方法进行了探讨。采用气相色谱质谱法(GC–MS)对主成分和杂质进行定性鉴定。用高效液相色谱法(HPLC–DAD)、气相色谱法(GC–FID)和差示扫描量热法(DSC)3种不同原理的方法对主成分定值。卡尔费休法测量水分,电感耦合等离子体质谱(ICP–MS)测量无机杂质。2,4,6-三氯酚纯度定值结果为99.3%,扩展不确定度为0.6%(k=2)。     

全二维气相色谱-飞行时间质谱/氢火焰离子化检测器对煤直接液化循环溶剂的定性与定量分析

建立了全二维气相色谱-飞行时间质谱/氢火焰离子化检测器(GC×GC-TOF MS/FID)对煤直接液化循环溶剂(CDLRS)定性定量的分析方法。采用TOF MS和FID两种检测器同时采集数据,并结合谱库检索、标准物质保留值对照、谱图解析、标准质谱图对照、全二维谱图特征以及提取化合物分子离子等定性方法,将TOF MS检测数据定性,然后将定性的烃类化合物以z值分类法分为18类;应用Chroma TOF数据处理软件将TOF MS数据的定性分类结果应用到FID的检测数据中,对TOF MS和FID采集的数据色谱峰面积归一化处理,实现CDLRS的半定量分析。GC×GC/FID定量结果显示:煤直接液化循环溶剂中饱和烃和芳烃分别占45.805%、53.938%,其中饱和烃主要为二环烷烃及三环烷烃,含量依次为14.644%、18.021%;芳烃主要为一环烷苯和二环烷苯,含量依次为19.759%、16.528%。该方法为CDLRS的定性定量提供了一种有效的分析方法。     

唇形科植物挥发油化学成分的GC/MS研究

在运用GC/MS技术的基础上采用HELP(直观推导式演进特征投影法)方法研究了九种唇形科植物的化学成分, 并以唇形科植物半枝莲为例详细介绍了HELP的解析过程. 应用总体积积分法测定各成分的相对百分含量. 鉴定出相对共有成分达70余种, 大多数为萜类化合物及其衍生物. 不同的唇形科植物的挥发油化学成分与特征成分有明显差异. 九种药材挥发性成分中均含有桉油精(Eucalyptol, 含量0.10%～1.01%)和芳樟醇(Linalool, 0.11%～3.05%). 利用GC/MS分析法结合化学计量学分辨方法鉴定挥发油化学成分, 比单独使用GC-MS法结果更准确、可靠.     

固相萃取-气相色谱/质谱法同时测定化妆品中的14种邻苯二甲酸酯类和5种己二酸酯类成分

建立了固相萃取-气相色谱/质谱(SPE-GC/MS)法同时测定化妆品中14种邻苯二甲酸酯类和5种己二酸酯类成分。样品经正己烷超声提取、中性氧化铝柱(AL-N)固相萃取纯化后,采用GC/MS(SIM)内标法进行定性定量分析。19种目标物在1～40μg/mL(BXA为5～200μg/mL)的范围内呈现良好的线性关系,相关系数0.9973～1.0000,检出限为0.07～1.68mg/kg,加标回收率为89.1%～106.7%,相对标准偏差为0.75%～5.93%(n=6)。该方法干扰小,重现性好,结果准确,适用于化妆品中邻苯二甲酸酯类和己二酸酯类成分的分析测定。     

蔬菜和食用菌中多种氨基甲酸酯农药残留的UPLC-MS/MS的确证方法

建立了蔬菜和食用菌中19种氨基甲酸酯农药残留的液相色谱串联质谱（UPLC-MS/MS）确证方法.实验方法采用丙酮和乙腈混合溶液提取,凝胶渗透色谱净化,经浓缩后由HPLC-MS/MS测定.实验结果表明：方法定性定量准确,灵敏度高,满足了国内外限量要求,具有较好的推广价值.回收率为70.1%~95.7%,RSD为1.63%~13.83%,方法最低检出限0.01 mg/kg.     

三重串联四级杆气质联用法测定化妆品中的三种邻苯二甲酸酯类增塑剂

建立了一种快速、灵敏、准确的三重串联四级杆气质联用(GC-MS/MS)法,将其用于同时检测化妆品中的三种邻苯二甲酸酯(邻苯二甲酸二丁酯、邻苯二甲酸丁基苄基酯、邻苯二甲酸二乙基己酯)增塑剂.化妆品经甲醇提取,HP-5MS柱分离,采用GC-MS/MS的多反应监测模式,以保留时间和离子对(母离子和子离子)信息比较定性,以母离子和响应值高的子离子进行定量.结果表明,该方法的检出限为12～28ng/g,相对标准偏差为1.6%～7.54%,目标物的加标回收率为86.4%～121.1%;该方法可用于检测日常化妆品中邻苯二甲酸酯的含量.     

GC/MS和ESI/MS/MS同位素内标法检测甲基丙二酸血症

以甲基丙二酸血症为对象,分别用GC/MS和ESI/MS/MS方法对该疾病进行了定性和定量检测.通过对样品前处理和分离条件的改善,对疾病的标识化合物之一甲基丙二酸进行了定量测定,其稳定性、精密度和回收率结果很好.同时比较了GC/MS和ESI/MS/MS两种方法的特点,发现两种方法的结合不仅可满足新生儿代谢疾病筛查的要求,同时还可对高危人群进行诊断.     

固相萃取-GC/MS法测定水样中20种有机氯农药

建立了用固相萃取小柱提取和净化、GC/MS定性定量同时测定水样中20种有机氯农药的方法。方法采用OasisHLB固相萃取小柱萃取富集水样,二氯甲烷洗脱,加入菲-d₁₀作为内标,利用GC/MS进行定性定量,步骤简便,线性响应良好,干扰小,方法检出限为0.21～0.72 ng/L（按水样1L计）,加标回收率为64.8%～122%,RSD为1.2%～11.0 %。成功利用该方法对广西实际河水样品进行了检测。结果表明方法可以同时满足环境水样中20种痕量有机氯农药的测定。     

高效液相色谱-串联质谱法测定卷烟中的儿茶酚

建立了一种高效液相色谱-串联质谱(HPLC-MS/MS)测定卷烟中儿茶酚的分析方法。样品经2.5 mol/L硫酸加热回流后用水蒸气蒸馏提取,C₁₈固相萃取柱富集净化后进行HPLC-MS/MS分析,采用甲醇-0.2%(v/v)的甲酸水溶液作为流动相进行梯度洗脱,以电喷雾负离子(ESI^-)扫描和多反应监测(MRM)模式对目标物进行定性和定量分析。目标物儿茶酚的含量在0.5~200 μg/kg时与峰面积呈良好的线性关系(r²=0.9989);在样品中添加高、中、低3个水平的标准品,其加标回收率在83.1%~98.6%之间,相对标准偏差(RSD)在1.9%~5.8%之间。应用本方法对6种市售卷烟样品进行了测试,结果从6种市售卷烟中均检出了儿茶酚。该方法操作简单、快速、灵敏度高,适用于卷烟中儿茶酚的检测。     

直接电喷雾离子阱质谱法快速表征烟叶

建立了一种快速、简单的同时检测烟叶中多酚类和非挥发性有机酸的电喷雾离子阱质谱方法。该方法采用水溶液萃取烟叶,萃取液无需色谱柱分离提纯,直接进入质谱检测,得到烟草质谱轮廓图。采用该方法对25种不同产地、不同等级的烟叶样品进行了测量,并结合模式识别的方法,对这25种烟叶进行了聚类分析,其结果基本符合烟草专家的等级划分。最后对各类烟叶进行了统计分析,得到了表征各类烟叶的平均质谱轮廓和各特征组分对区分烟叶贡献大小。表明该方法可以用于辅助烟叶等级划分及卷烟配方设计。     

Multivariate statistical analysis of tobacco of different origin, grade and variety according to polyphenols and organic acids

The aim of this work was to determine the concentration of polyphenols, organic acids in tobacco of different areas, grades and varieties by ultra-performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS) and to achieve statistical classification by principal component analysis (PCA) and linear discriminant analysis (LDA). The obtained results revealed that tobacco of different varieties can be correctly classified according to the contents of polyphenols or organic acid. The results of PCA showed that different grades and geographic regions cannot completely be discriminated using polyphenols or organic acid as independent variables. However, there were marked differences in special class from the same type or grade tobacco. At the same time, the results of LDA also showed that the samples were correctly classified at 100% for different varieties of tobacco, but only 55.3% and 60% for different grades and areas, respectively. These results demonstrated that the composition of polyphenols and organic acids can be used as the useful variables to characterize the type and the special class or grade of tobacco.     

Analytical determination of nicotine in tobacco leaves by gas chromatography–mass spectrometry

A preliminary investigation using gas chromatography–mass spectrometry (GC–MS) to analyze the nicotine contained in tobacco leaves was carried out. Nicotine is an alkaloid and tobacco leaves was extracted with methanol and determined by GC–MS. The detection limit for nicotine was at the ppm level for non selective monitoring and the nanogram level for selective detection. This is a simple chromatography–mass spectrometry method for the analysis of nicotine in tobacco leave. Compared to other currently utilized methods for the detection of nicotine in tobacco leaves, the GC–MS provided advantages of high sensitivity, nicotine specific detection and lower instrumentation cost.     

A liquid chromatography–tandem mass spectrometry method to simultaneously determinate dichlorvos and phoxim in tobacco

A simple pretreatment method with liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed and validated to simultaneously determine dichlorvos and phoxim in tobacco and soil matrices. Satisfactory linearity (R² ≥ 0.9991) of the method was obtained for both analytes. The limits of detection and limits of quantification for dichlorvos and phoxim in three matrices were 0.0015–0.006 and 0.005–0.02 mg/kg, respectively. Average recoveries were 78.24–92.21% for dichlorvos and 76.62–100.51% for phoxim in soil, green tobacco leaves and cured tobacco leaves. The intra‐ and inter‐day relative standard deviations were <6%. The established method was successfully applied for the residual analysis of dichlorvos and phoxim in real soil and tobacco samples. The results indicated that the established method could be used to detect trace amounts of dichlorvos and phoxim in tobacco. The data could also help the Chinese government establish maximum residue limits of dichlorvos and phoxim on tobacco and establish proper and safe use of dichlorvos and phoxim on tobacco plants in China.     

微波辅助萃取-气相色谱-负化学电离/电子轰击电离-飞行时间质谱法测定烟草中农药残留

建立了微波辅助萃取结合气相色谱-飞行时间质谱(GC-TOF MS)技术在负化学电离(NCI)源和电子轰击电离(EI)源两种模式下测定烟草中24种农药残留的分析方法。烟叶样品于100℃下用二氯甲烷-正己烷(3:1, v/v)混合溶剂微波萃取10 min,萃取液经弗罗里硅土固相萃取柱净化后进行检测分析。在NCI源和EI源质谱模式下,24种农药的线性关系均良好(r²>0.99),相对标准偏差分别小于8.6%和9.1%,定量限分别为0.3~6.9 μg/kg和10.2~44.9 μg/kg,加标回收率分别为75.2%~94.8%和75.0%~95.1%。比较两种离子源模式下的色谱图和质谱图,NCI源模式较EI源模式的选择性好、灵敏度高、基质干扰小、图谱简单易于解析,检出限低一个数量级以上,在分析低含量、复杂基质的样品时更具优势。     

Selective determination of tobacco‐specific nitrosamines in mainstream cigarette smoke by GC coupled to positive chemical ionization triple quadrupole MS

A rapid method for the selective determination of four kinds of tobacco‐specific nitrosamines, N‐nitrosonornicotine, N‐nitrosoanatabine, N‐nitrosoanabasine and 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone, in mainstream cigarette smoke was developed by GC coupled to positive chemical ionization triple‐quadrupole MS. After mainstream cigarette smoke was collected on a cambridge filter pad, the particulate matter was extracted with 0.1 M HCL aqueous solution, cleaned by positive cation‐exchange solid extraction, and finally injected into GC–MS/MS using isotopically labeled analogues as internal standards. Excellent linearity was obtained over the concentration range of 0.5–200.0 ng mL^?1 for all tobacco‐specific nitrosamines with values for correlation coefficient between 0.9996–0.9999. Limits of detection of each tobacco specific nitrosamine varied from 0.023–0.028 ng cig^?1, and lower limits of quantification varied from 0.077–0.093 ng cig^?1. The recovery of each tobacco specific nitrosamine was from 90.0–109.0%. The relative standard deviations of the intra‐day and inter‐day precisions were 3.1–5.8 and 3.9–6.6, respectively. This method was applied to reference and domestic cigarettes. The result showed that the method was consistent with traditional methods and can be used as an effective approach for the routine analysis of tobacco‐specific nitrosamines.     

气相色谱-三重四极杆质谱法同时测定烟丝中73种香气物质

建立了气相色谱-三重四极杆质谱(GC-MS/MS)同时测定烟丝中73种香气物质的分析方法。样品用无水乙醚振荡提取,提取液经过滤后直接进入DB-5MS色谱柱(30 m×0.25 mm,0.25μm)分离,通过优化质谱参数,可有效降低复杂基质和重叠峰的干扰,同时采用多反应监测(MRM)模式测定,内标法定量。结果表明,目标物在各自的线性范围内线性关系良好(r~20.99),低、中、高3个水平的加标回收率为70.0%~122.3%,相对标准偏差(RSD)为1.6%~20.4%。该方法具有前处理简单、准确灵敏的特点,适用于烟丝样品中73种香气物质的检测。     

Metabolomics study of cured tobacco using liquid chromatography with mass spectrometry: Method development and its application in investigating the chemical differences of tobacco from three growing regions

Cured tobacco is an important plant material. Component studies are a big challenge for its significantly diverse chemical properties and vastly different concentrations. In this work, liquid chromatography with quadrupole time‐of‐flight mass spectrometry was used to perform a metabolomics study of cured tobacco owing to its efficient separation and detection of semipolar metabolites. A solvent of methanol/water (8:2, v/v) and 30 min of ultrasound time were found to be optimal to perform extraction. 95, 92, and 93% of metabolite features had within 20% of coefficient of variation for repeatability, intraday and interday precision analysis, respectively, indicating a good stability of the method developed. 113 metabolites were identified in cured tobacco based on accurate mass, retention time, and MS/MS fragments. The developed method was applied to a metabolomics study of cured tobacco from three growing regions. Forty three metabolites were found to be contributed to the classification. It is shown that the developed method can be applied to metabolomics analysis of plant materials.     

气相色谱-电子轰击离子源质谱法分析卷烟和烟叶中29种农药的残留

开展了卷烟和烟叶中有机氯、有机磷和拟除虫菊酯3类29种农药残留的气相色谱-电子轰击离子源质谱(GC-EI/MS)的分析方法研究。优化与选择了卷烟和烟叶样品的前处理条件,样品经正己烷-丙酮(体积比为1∶1)混合提取剂超声提取、Florisil硅土和中性氧化铝双净化剂固相萃取柱净化、二氯甲烷-正己烷(体积比为95∶5)混合洗脱剂洗脱和浓缩后,以磷酸三苯酯(TPP)为内标物,采用GC-EI/MS的选择离子监测方式(SIM)进行定性和定量分析。当样品的加标水平为20,50,100 μg/kg时,加标回收率为70%～110%,相对标准偏差在2%～8%之间;除了甲氰菊酯、氯菊酯和溴氰菊酯的方法检出限(LOD)分别为1.85,1.74与2.54 μg/kg外,其余的26种农药的LOD均小于0.8 μg/kg;线性范围为5.0～500.0 μg/kg,相关系数都大于等于0.9994。此分析方法已成功地应用于卷烟和烟叶样品中3类29种痕量农药残留的分析