利用毛细管电泳和主成分分析判断海洛因地理来源

对在中国境内缴获的海洛因样本进行地理来源判断.采用动态涂层毛细管电泳技术(CE)对300份海洛因样本进行生物碱定量检测,并利用主成分分析建立二维教学模型.实现了对中国境内缴获的海洛因样本地理来源的推断.     

利用毛细管电泳和判别分析判断海洛因地理来源

对在中国境内缴获的海洛因样本进行地理来源判断.采用动态涂层毛细管电泳技术(CE)对海洛因样本进行生物碱检测,并利用判别分析法对检测数据进行统计学分析,达到了对中国境内缴获的海洛因样本进行地理来源推断的目的.     

基于光谱融合-特征提取的海洛因及其添加剂无损分类研究

在近年来的多数治安案件中,有不少是由形形色色的毒品所引起的。为了提高检验的效率,降低检验成本,实现对海洛因样本主成分及添加剂的无损分类,提出了一种基于光谱融合,主成分分析和判别分析的鉴别方法。采集并获取了不同质量分数和添加剂共计45个海洛因样本的红外光谱,选择一阶求导、多元散射校正、Savitzky-Golay平滑和峰面积归一化开展预处理工作,并利用主成分分析进行特征变量提取和采用Fisher判别分析构建判别分类模型。实验对单独的原始光谱数据,一阶导数光谱数据和融合后的光谱数据进行比较。无论是对海洛因主成分的质量分数进行分类,还是对海洛因的添加剂分类,单一的分类模型都仅能实现66.7%～88.9%的准确区分。结果表明,基于融合的光谱数据构建的判别模型分类准确率更高,对主成分质量分数和海洛因添加剂的分类,均能达到100.0%。利用红外光谱数据融合技术结合主成分分析和判别分析达到了降低检验成本且无损的目的,能够最大程度的限制毒品的流动,对今后的毒品检测和维护社会治安稳定具有一定的贡献。     

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)。     

气相色谱/氢火焰离子化检测法分析烷基化物料中的C4氟代烃

以实验室合成的氟代叔丁烷、氟代仲丁烷、氟代正丁烷为参考,建立了烷基化物料中C4氟代烃的气相色谱/氢火焰离子化检测(GC/FID)分析方法。提出了利用气相色谱/原子发射光谱(GC/AED)按元素响应的特点求算C4氟代烃在GC/FID上相对校正因子的方法。方法采用OV-225(50 m×0.25 mm i.d.×0.25 μm)和SE-54(44 m×0.22 mm i.d.×0.25 μm)串联柱为分析柱,FID为检测器,校正归一化或间接外标方法进行定量,具有重复性好、应用移植便利、操作简单等特点,对氟代叔     

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。     

指纹图谱结合化学计量学方法研究新疆薰衣草精油成分

采用水蒸汽蒸馏法(SD)提取薰衣草挥发油,气相色谱-质谱联用(GC-MS)技术分析其化学成分及相对含量。通过气相色谱法(GC)建立其色谱指纹图谱,并结合化学计量学方法对其进行品种鉴别。3种薰衣草精油中共检测29种挥发性化学成分,其中共有成分有18种;31批薰衣草样本的GC指纹图谱相似度均大于0.9,符合指纹图谱相似度的要求,利用主成分分析法(PCA)和聚类分析法(HCA)对GC指纹图谱进行识别,可直观地区分薰衣草品种,该方法可应用于薰衣草质量控制及品种鉴别。     

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.     

海洛因与甲基苯丙胺毒品滥用者毛发特征分析的比较

根据海洛因和甲基苯丙胺滥用者毛发中毒品及其代谢物的分布特点,通过实验比较了两类毒品滥用者毛发的分析特点。海洛因吸食者毛发采用甲醇超声释放待测物,而后直接调整pH值进行液相萃取,萃取物挥干后进行衍生化并进行GC/MS检测;甲基苯丙胺吸食者毛发在碱性条件下消解,然后采用小体积萃取,直接在提取液中衍生化,并进行GC/MS检测。通过空白毛发标准添加6-单乙酰吗啡、吗啡和可待因进行分析,3种鸦片类毒品最小检测限均小于3μg/g,RSD(n=5)为2.5%~9.6%;通过空白毛发标准添加苯丙胺、甲基苯丙胺、3,4-(亚甲二氧基)苯丙胺和3,4-(亚甲二氧基)-甲基苯丙胺进行分析,4种苯丙胺类毒品的最小检测限为0.05μg/g,RSD(n=5)为5%~14%。     

稻米代谢组学分析方法的建立及在产地溯源中的应用

采用气相色谱-串联四极杆飞行时间质谱(GC/Q-TOF MS)建立了稻米的代谢组学分析方法,并将其应用于产地溯源。利用D-最优设计对提取溶剂进行优化,通过偏最小二乘分析法考察了不同溶剂对代谢物提取效率的影响。考察了衍生试剂种类、衍生温度及时间对代谢物检测的影响,最终确定分析条件为:甲醇-水(1∶1)为提取溶剂,N-甲基-N-三甲基硅基三氟乙酰胺-三甲基氯硅烷(MSTFA-TMCS,99∶1)于60℃条件下衍生1 h。选取10种代谢物考察仪器精密度、方法重现性和衍生产物稳定性,相对标准偏差(RSD)均小于9%,证明了方法的可靠性。结合Mass Profiler Professional(MPP)软件,以主成分分析(PCA)法区分黑龙江省4个地区的29个绥粳4号稻米样本,分类效果显著。对显著变化(P0.05,倍率变化≥2)的差异性代谢物进行鉴定,确定了11种特征标记物。结果表明,利用GC/Q-TOF MS建立代谢组学分析方法,结合主成分分析鉴别稻米产地具有可行性,为大米市场的规范和资源开发利用提供了依据。     

Simplification of determination method for standard materials using post-column reaction GC/FID

For the simple and fast preparation of highly reliable standard materials, a post-column reaction GC/FID system was developed and evaluated on the mixture of oxygen-containing organic compounds. The oxygen-containing organic compounds mixing solution were determined with the post-column reaction GC/FID system using n-dodecane as an internal calibration standard. Required value of relative expanded uncertainty as an original source of SI-traceable standard materials was within 1% and it aimed at this value as accuracy of the quantitative analysis. The results showed good agreement between the prepared concentrations and analytical values using post-column reaction GC/FID system. These results indicated that the post-column reaction GC/FID system would be used for getting SI-traceable values.     

汽油样品类型的模式识别研究与应用

研究了应用化学计量学方法解决汽油单体烃的气相色谱分析中单体烃定性库的自动选择问题。通过提取汽油单体烃谱图中的29个组分及其含量信息作为特征值,利用主成分分析法对不同工艺得到的催化裂化汽油、焦化汽油、直馏汽油、重整汽油和烷基化汽油进行分类,结合相似分析方法(即SIMCA方法)建立了各类汽油样本的类模型,借助这些类模型可以实现对未知样本的类型判别。所提出的识别方法可方便快速地判别待分析样品所属的汽油类别,并据此推荐适合该样品的定性模型库,从而实现汽油单体烃的快速、自动分析。     

Determination of Deoxynivalenol in Poultry Feed by Three Gas Chromatographic Detection Techniques

Three different gas chromatographic detection techniques were applied for the determination of deoxynivalenol (DON) present in poultry feed samples. Extraction and cleanup procedures were kept the same for GC–FID, GC–ECD and GC–MS methods. Although all three GC methods provided good and comparable results, but more attention was focused on GC–FID due to its lower cost and easy availability in many laboratories. Therefore, a short 15 m DB-1 short column was introduced for the determination of DON in poultry feed to reduce the time of analysis and initial cost of column. An inter-laboratory study for GC–FID was performed in two laboratories using four naturally DONS-contaminated feed samples and one spiked with standard. The relative standard deviations for repeatability (RSDr) and relative standard deviations for reproducibility (RSD_R) of naturally contaminated feed were in the range 5–23 and 11–24 %, respectively. The Horwitz Ratio (HORRAT) was less than 1.0 in each sample. From the spiking test, recovery, RSDr, RSD_R and value of HORRAT were 93, 5, 11 and 0.6 %, respectively. For GC–FID method, limit of quantification was found to be 6 μg kg^?1. Thus, GC–FID method using 15 m DB-1 capillary column is sensitive and validated analytical method for the determination of DON for poultry feed.     

Coupling stir bar sorptive extraction‐dispersive liquid–liquid microextraction for preconcentration of triazole pesticides from aqueous samples followed by GC‐FID and GC‐MS determinations

Stir bar sorptive extraction (SBSE) combined with dispersive liquid–liquid microextraction (DLLME) has been developed as a new approach for the extraction of six triazole pesticides (penconazole, hexaconazole, diniconazole, tebuconazole, triticonazole and difenconazole) in aqueous samples prior to GC‐flame ionization detection (GC‐FID). A series of parameters that affect the performance of both steps were thoroughly investigated. Under optimized conditions, aqueous sample was stirred using a stir bar coated with octadecylsilane (ODS) and then target compounds on the sorbent (stir bar) were desorbed with methanol. The extract was mixed with 25 μL of 1,1,2,2‐tetrachloroethane and the mixture was rapidly injected into sodium chloride solution 30% w/v. After centrifugation, an aliquot of the settled organic phase was analyzed by GC‐FID. The methodology showed broad linear ranges for the six triazole pesticides studied, with correlation coefficients higher than 0.993, lower LODs and LOQs between 0.53–24.0 and 1.08–80.0 ng/mL, respectively, and suitable precision (RSD < 5.2%). Moreover, the developed methodology was applied for the determination of target analytes in several samples, including tap, river and well waters, wastewater (before and after purification), and grape and apple juices. Also, the presented SBSE‐DLLME procedure followed by GC‐MS determination was performed on purified wastewater. Penconazole, hexaconazole and diniconazole were detected in the purified wastewater that confirmed the obtained results by GC‐FID determination. In short, by coupling SBSE with DLLME, advantages of two methods are combined to enhance the selectivity and sensitivity of the method. This method showed higher enrichment factors (282–1792) when compared with conventional methods of sample preparation to screen pesticides in aqueous samples.     

Determination of Atenolol in Pharmaceutical Preparations by Gas Chromatography with Flame Ionization and Mass Spectrometric Detection

The present work describes the methodology and validation of gas chromatography with flame ionization (FID) and mass spectrometric (MS) detection after derivatization with N-Methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) for determination of atenolol with an internal standard (metoprolol) in pharmaceutical preparations. The linearity was established over the concentration range of 0.5–20 μg/mL for GC/FID and 12.5–500 ng/mL for GC/MS method. The intra- and inter-day relative standard deviation was less than 4.72 and 5.80%, respectively. Limit of quantification was determined as 500 ng/mL and 12.5 ng/mL for GC/FID and GC/MS, respectively. No interference was found from tablet excipients at the selected assay conditions. Developed GC/FID and GC/MS methods in this study are accurate, sensitive, and precise and can be easily applied to Tensinor tablet as pharmaceutical preparation.     

Automated on-line HPLC-HRGC: Instrumental aspects and application for the determination of heroin metabolites in urine

A fully automated on-line HPLC-HRGC instrument is described. Samples are loaded into an HPLC autosampler. Pre-separation is carried out, automatically transferring the previously determined HPLC fraction to GC. Total HPLC fractions are introduced into GC, using the on-column or the loop-type interface, depending on the solvent evaporation technique applied. The HPLC column is automatically backflushed with a suitable solvent during GC analysis. The instrument was used for analyzing heroin metabolites, particularly morphine, in urine samples. Raw urine extracts were injected into HPLC and analyzed by GC using FID.     

气相色谱/原子发射检测法测定毒死蜱中的杂质

 利用气相色谱 /原子发射检测 (GC/AED)法 ,并通过元素内标测定 ,对农药毒死蜱产品分别进行碳 (4 96nm和193nm)、氯 (4 79nm)和硫 (181nm)等通道的选择性定量检测。根据检测结果及由气相色谱 /质谱 (GC/MS)测得的分子结构式 ,分别计算杂质的质量分数。由此可知 ,各组分从不同通道得到的定量结果比较接近 ,对杂质的最大相对误差不超过 5 8%。在无纯物质作标样的条件下 ,该方法比气相色谱 /火焰离子化检测 (GC/FID)面积归一化法更为可靠 ,可作为对农药及其他复杂有机混合物准确、方便的定量方法。     

Gas chromatographic determination of amino acids via one-step phase-transfer catalytic pentafluorobenzylation-preconcentration

The gas chromatographic determination of amino acids via their simultaneous extraction, preconcentration and pentafluorobenzylation is reported. Using phase-transfer catalysis (PTC), the amino acids under study were transformed to their pentafluorobenzyl adducts. The method was tested for different catalysts and tetrabutylammonium bromide provided favorable features in comparison to the other PTCs. The derivatization procedure was optimized and the best reaction conditions are given. With the exception of arginine, 19 amino acids were converted to volatile derivatives and analyzed with GC/MS and GC/FID at low concentration levels with acceptable sensitivity and good reproducibility. The LODs were found to range from 0.7 to 2.3microM for the GC/MS analyses and from 1.7 to 6.9microM for GC/FID analyses. The method practicability and applicability were confirmed by the analysis of urine, fruit juice and wheat flour for the determination of the amino acids under study. Protein-bound amino acids were analyzed after an alkaline hydrolysis step with 5M NaOH applying this method to wheat flour with an overall procedure duration less than 12h. The optimized protocol was applied to these samples without any pretreatment and their amino acid concentrations were calculated from the appropriate calibration plots.     

Comparison of comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry and gas chromatography-mass spectrometry for the analysis of tobacco essential oils

A sample of tobacco essential oil was analyzed using gas chromatography-mass spectrometry (GC/MS) and comprehensive two-dimensional gas chromatography coupled to a time-of-flight mass spectrometry (GC × GC/TOFMS), respectively. In the GC/MS analysis, serially coupled columns were used. By comparing the GC/MS results with GC × GC/TOFMS results, many more components in the essential oil could be found within the two-dimensional separation space of GC × GC. The quantitative determination of components in the essential oil was performed by GC × GC with flame ionization detection (FID), using a method of multiple internal standards calibration.