精油中挥发性成分GC/FTIR与GC/MS联合分析

采用同时蒸馏萃取(SDE)法获得了香紫苏(Salvia sclarea L.)精油,利用气相色谱/傅里叶变换红外光谱联用(GC/FTIR)和气相色谱/质谱联用(GC/MS)相结合的手段,对其挥发成分进行了定性和定量分析,着重讨论了GC/FTIR在精油分析中的应用研究。通过不同波数官能团(Gram-Schmidt)重建红外光谱图、红外光谱差谱技术及质谱等相互验证的方法,大大提高了香紫苏油挥发成分的定性分析准确性。     

三氟乙酸酐衍生化GC/MS/MS方法检验尿中吗啡

建立了人体尿中吗啡和O~6-单乙酰吗啡的衍生化GC/MS/MS定性、定量分析方法。以SKF_(525a)为内标,三氟乙酸酐为衍生化试剂,采用DB5-MS色谱柱对衍生化产物进行分析。尿中吗啡和O~6-单乙酰吗啡的质量浓度在0.05—10μg/mL范围内线性良好,线性相关系数r均为0.9901;方法回收率为65%—86%。检出限均为0.05ng/mL。该法操作简单,灵敏度高,适合作为法医毒物分析的常规方法。     

气相色谱-质谱测定香烟灰中的多环芳烃

采用正己烷-二氯甲烷(体积比为1:1)索氏提取,硅胶柱净化技术,用气相色谱-质谱(GC-MS)的分段选择性离子监测(SIM)对烟灰中多环芳烃(PAHs)进行定性定量分析.通过优化19种PAHs的分离条件,SIM法实现烟灰中19种PAHs的同时测定,检出限达到0.02ng/mL.该法灵敏、准确,适合于烟灰等食品中多环芳烃含量的测定.     

基于荧光光谱的多环芳烃定量分析方法研究

多环芳烃(polycyclic aromatic hydrocarbons, PAHs)由于具有毒性、遗传毒性、突变性和致癌性,会对生态环境及人体健康造成诸多危害。荧光光谱法由于灵敏度高、选择性好和完整程度好等优点已广泛用于PAHs的检测。腐殖酸在环境中常与PAHs共存,由于其荧光特性严重影响了PAHs的精确检测,因此研究二者混合物中PAHs的定量分析至关重要。以典型PAHs苯并[g, h, i]苝为研究对象,对其与腐殖酸的混合物进行荧光检测,通过偏最小二乘法建模对混合物中PAHs进行定量分析。实验结果表明,预测集样本的决定系数R²为0.967 8,预测均方差RMSE为0.002 4 mg·L^-1,达到了较好的预测效果。     

生物气溶胶红外光谱信号预处理算法研究

被动傅里叶变换红外(FTIR)遥感是一种具有应用潜力的生物气溶胶远程探测技术。红外遥感测量中目标光谱特征上往往存在噪声信号和基线漂移。而生物气溶胶的光谱特征相对较宽,传统的基线校正方法都不适用。由于生物气溶胶红外光谱和不同形式的基线漂移都是非高斯信号,把非高斯性作为独立性度量,基于独立成分分析(ICA)技术设计了生物气溶胶红外光谱信号的预处理算法。试验结果表明,该算法可以把未知干扰成分、基线漂移等作为独立分量分离出来,从而不影响进一步的定性、定量分析。     

基于三维荧光光谱结合小波压缩与APTLD对水中多环芳烃测定

基于三维荧光光谱结合小波压缩与交替惩罚三线性分解(APTLD)对水中多环芳烃(PAHs)进行定性和定量分析,实验以萘(NAP)、芴(FLU)、苊(ANA)为测量样品。首先用FS920荧光光谱仪测量获得样品的三维荧光光谱数据,对数据进行激发和发射校正且去散射,得到真实光谱。为了解决三维荧光光谱数据的冗余信息,通过小波变换对实验光谱数据进行压缩,其压缩分数和数据恢复分数分别大于92%和95%。用APTLD对压缩后的光谱数据进行分析,体现了二阶优势,实验结果表明,在PAHs的荧光光谱严重重叠和有干扰物共存下,该方法仍能准确地测定,其回收率为94%~98%、预测均方根误差小于0.29 μg·L-1。     

GC/MS解析中二苯硫脲的中性丢失

温和条件常温常压下 ,苯胺与CS2 在AlCl3 催化作用下反应 ,对反应混合物用乙醇进行重结晶获得白色片状晶体 ,GC/MS分析表明该晶体为异硫氰酸苯酯。然而 ,用熔点测定、HPLC/MS/MS ,FTIR ,UV和1HNMR等手段对此晶体进行分析 ,确定其为二苯硫脲。结合GC/FTIR谱图 ,研究了二苯硫脲的质谱裂解机理。实验结果表明二苯硫脲质谱裂解中可能发生了中性丢失 ,丢失了中性分子苯胺 ,生成的异硫氰酸苯酯分子离子由于π电子共轭而致稳。此机理同样能合理解释二苯脲和二萘硫脲的GC/MS谱图中只出现异氰酸苯酯和异硫氰酸萘酯分子离子峰的现象。     

气相色谱-质谱中定量分析技术的应用

本文对气相色谱－质谱（GC－MS）定量分析技术及其在我国的应用进行了综述，较详细地阐述子峰匹配、质量色谱和选择离子检测3种定量分析与应用，共引用文献39篇。     

土壤质地对多环芳烃荧光工作曲线影响的研究

土壤质地对多环芳烃(PAHs)的荧光检测造成不可忽视的干扰,论文在探究不同二氧化硅含量,相同菲浓度土壤样品荧光强度与漫反射率变化关系的基础上,建立了一种基于近红外漫反射光谱减小土壤质地对PAHs荧光强度影响的校正方法。校正前后荧光强度与PAHs浓度之间线性拟合的复相关系数R²分别为5.42×10^-6和0.94。研究结果表明：所建立的校正方法可有效减小土壤中二氧化硅对荧光定量分析PAHs工作曲线的影响。     

电火花诱导击穿光谱技术的发展及研究应用分析

电火花诱导击穿光谱(SIBS)技术是一种基于原子发射光谱学的物质浓度与成分的定性、定量分析技术。与传统的实验室分析技术如电感耦合等离子体原子发射光谱(ICP-AES)、原子吸收光谱(AAS)、质谱(MS)等相比具有实时、实地、在线快速检测、高灵敏度以及低成本、小体积、维护简单等优点。目前对该技术已有的研究集中在气溶胶成分分析、土壤成分分析、金属颗粒物浓度检测、水泥成分分析等方向,在环境监测、工业卫生、食品安全、生物医疗等领域都有广泛且良好的应用前景。从SIBS技术的基本原理入手,综述了其光谱分析的原理,即利用高压脉冲电源产生的电火花激发被测物体表面,使被测物体在电源正负极间产生等离子体,利用光谱仪光纤探头收集等离子体冷却过程中通过跃迁放出的光子与特征辐射谱线,由于不同元素具有独特的特征谱线,进而可以根据特征谱线对被测物质进行成分与浓度的定性和定量分析;接着分析了影响SIBS技术光谱图像和光谱分析的相关因素如脉冲电源参数、电极材料与入射角度和等离子体本身特性等,并定量地指出了部分因素与光谱信号强弱的关系;综述了该技术在发展过程中的一些技术革新和应用创新如激光+电火花诱导(LA-SIBS)...     

基于密度泛函理论的多环芳烃硝基衍生物的生物毒性预测

采用密度泛函理论（DFT）中的B3LYP方法,在6-311++G（d,p）基组水平下对16种多环芳烃（PAHs）及6种多环芳烃硝基衍生物进行了拉曼光谱、极化率、偶极矩、热力学、结构优化及能量等40种参数进行计算。以13种PAHs对发光菌的－lgEC₅₀值做因变量,以另外3种多环芳烃数据作为验证,构建了基于量子化学参数的PAHs毒性定量结构-活性相关（QSAR）模型,预测PAHs硝基衍生物的毒性。经验证,所建立的QSAR模型的模拟系数为0.816,模型预测的PAHs硝基衍生物毒性排序与文献报道的PAHs硝基衍生物对鼠伤寒沙门氏菌的毒性排序一致,表明所建模型可用于PAHs及其硝基衍生物的生物毒性预测,从而为控制和预测PAHs及硝基衍生物毒性提供理论依据。     

Leaching of polycyclic aromatic hydrocarbons (PAHs) from industrial wastewater sludge by ultrasonic treatment

Ultrasonic treatment for sludge reduction in wastewater treatment plants (WWTPs) can substantially affect the fate of trace pollutants. However, their fates in the different phases of sludge and mass balances have rarely been reported. In this study, wastewater sludge samples were ultrasonicated at 600 W for 0–30 min. Then, the leaching of the 16 priority polycyclic aromatic hydrocarbons (PAHs) from the sludge solids (sediment) to the liquid phase (supernatant) was investigated. The total concentration of PAHs (∑₁₆ PAHs) in the sludge sediment (2.10 μg/g) was comparable with those of previous worldwide studies. Among the 16 PAHs, naphthalene and acenaphthylene were dominant. The total concentrations of PAHs in the supernatant generally increased with sonication time, indicating that PAHs associated with sludge materials, such as microorganisms, were released into the supernatant. Lighter and more water soluble PAHs were released preferentially into the supernatant in dissolved form, whereas heavier and more hydrophobic PAHs were strongly bound to particles. According to mass balance calculations, 21% of the PAHs in the sludge sediment moved to the supernatant without discernible sonodegradation. An additional experiment for degradation of PAHs supported this interpretation, and several reasons for the no significant sonodegradation were discussed. This result suggests that leaching trace pollutants may significantly contaminate the sludge filtrate after ultrasonic treatment, and therefore their fates should be investigated.     

煤中氯对多环芳烃生成的影响研究

本文在管式炉上研究了煤中氯对多环芳烃生成的影响,测定了煤中氯含量不同时多环芳烃生成量的变化,并分析了在不同气氛下不同含氯量的煤燃烧时多环芳烃与二(?)英生成的相互关系.实验结果表明,在空气中燃烧及氮气气氛热解条件下,随着氯含量的增加,多环芳烃呈减少趋势;氯代反应是导致多环芳烃生成量减少的一个主要原因.     

Simultaneous imaging of Mie scattering,PAHs laser induced fluorescence and soot laser induced incandescence to a lab-scale turbulent jet pulverized coal flame

In this study, transient soot formation processes in a small-scale jet burner (CRIEPI burner) were investigated by simultaneous measurements of coal particles, polycyclic aromatic hydrocarbons (PAHs) and soot. Pairs of simultaneous measurements of “Mie scattering measurement for coal particles with laser induced fluorescence (LIF) for PAHs” and “LIF for PAHs with laser induced incandescence (LII) for soot” were performed to understand the transitive formation processes of soot formation in pulverized coal flame, whose signals were successfully separated. Findings in the present study are as follows. Coal particles, PAHs and soot were distributed in this order in radial direction from the central axis. Existing regions of coal particles, PAHs and soot were overlapped from the time averaged viewpoint while there were few overlapping areas of coal particles, PAHs and soot from the instantaneous viewpoint. This result indicates that a long time is required for the formation of soot from 2 to 3 rings PAHs through larger PAHs.     

Structural and electronic properties of linear and angular polycyclic aromatic hydrocarbons

The structural and electronic properties of linear and angular polycyclic aromatic hydrocarbons (PAHs) have been studied by ab initio calculations. We show that the HOMO–LUMO gaps of linear and angular PAHs are inversely proportional to their width and length and angular PAHs always exhibit larger HOMO–LUMO gaps than their linear isomers, indicating the relative higher kinetic stability for angular PAHs. The frontier orbitals of HOMO and LUMO are localized at the zigzag edges in linear PAHs, while they are distributed uniformly over the molecules in angular PAHs. These results offer key insight for understanding the size and topology depending effects, which is of great use for experimental syntheses of PAHs with specific electronic properties.     

煤燃烧过程中铜对多环芳烃生成的影响

研究了两种燃烧方式煤燃烧过程中金属铜的添加对多环芳烃生成的影响。结果表明:随着铜煤质量比的增加,管式炉煤燃烧多环芳烃生成浓度是减少的;流化床煤燃烧多环芳烃生成浓度是增加的,但要小于管式炉条件下两个数量级。多环芳烃生成毒性分布类似于多环芳烃生成浓度分布。而单个多环芳烃生成有着较大区别,同燃烧方式、存在状态、铜的含量等有较大关系。在燃烧温度下,铜的添加主要对高环物质的催化作用较为明显。     

层流预混火焰PAHs形成的反应机理模型

本文着重讨论层流预混火焰中,碳黑的先驱多环芳烃(PAHs)形成的化学反应动力学机理。该机理包括101种组分、546个基元反应。通过与实验结果的比较表明,该模型能够较好地预报碳氢燃料预混火焰中PAHs的生成过程。计算结果还表明当量比和压力PAHs的生成与排放具有重要影响,且存在一个化学当量比,在此当量比下,PAHs的浓度达到极大值。     

Trace analysis of polycyclic aromatic hydrocarbons using calixarene layered gold colloid film as substrates for surface‐enhanced Raman scattering

A surface‐enhanced Raman scattering (SERS) active substrate for the detection of polycyclic aromatic hydrocarbons (PAHs) was developed, which used 25, 27‐dimercaptoacetic acid‐26, 28‐dihydroxy‐4‐terbutyl calix[4]arene (DMCX) to functionalize a gold colloid film. This SERS‐active substrate prepared by self‐assembly method exhibits a high sensitivity, especially for the detection of PAHs. With the use of this SERS‐active substrate and with the application of the shifted excitation Raman difference spectroscopy (SERDS) technique, Raman signals of pyrene and anthracene in aqueous solutions at low concentration level (500 pM) can be obtained. Moreover, because PAHs are blocked from being directly adsorbed on gold colloid by DMCX and the photochemical reactions of adsorbates are avoided, the Raman bands of PAHs adsorbed on DMCX‐fuctionalized gold colloid film can be one‐to‐one correspondence with those of solid PAHs, and additionally, this SERS‐active substrate can be easily cleaned and reused. The obtained results demonstrate that the DMCX‐functionalized gold colloid films prepared by self‐assembly method have great potential to be developed to an in situ PAHs detection substrate. Copyright © 2012 John Wiley & Sons, Ltd.     

激光诱导纳秒时间分辨荧光猝灭法原位研究菲及烷基菲与腐植酸相互作用

利用激光诱导纳秒时间分辨荧光(laser-induced nanosecond time-resolved fluorescence,LITRF)猝灭法原位研究腐植酸(humic acid,HA)分别与母环多环芳烃(polycyclic aromatic hydrocarbons,PAHs)菲(phenanthrene,Phe)及烷基PAHs 9-乙基菲(9-Ethylphenanthrene,9-EP)和惹稀(retene,Ret)相互作用,考察HA对母环及烷基PAHs结合特性差异与机制,对了解PAHs环境行为及生物有效性有重要意义。结果表明,通过改变延迟时间(50ns)可有效消除HA荧光干扰,实现游离Phe,9-EP及Ret浓度直接测定。利用Freundlich非线性等温吸附模型描述Phe,9-EP和Ret与HA结合特性,LITRF猝灭法与传统荧光法获得的模型拟合参数及单点结合系数结果一致。其中,参数n小于1,表明Phe,9-EP及Ret与HA均以非线性形式结合,且9-EP和Ret非线性程度高于Phe;相同给定平衡浓度下,HA与9-EP和Ret单点结合系数KOC大于Phe,而9-EP和Ret结合能力相近,且PAHs与HA结合系数均随给定浓度增加而降低。疏水性、取代基及与HA疏水空腔适应能力决定特定PAHs与HA结合特性。通过荧光寿命分析,HA存在下Phe,9-EP和Ret寿命分别为36.90,35.34和35.13ns,与未加入HA时的36.36,35.34和35.84ns无明显差异,表明Phe,9-EP和Ret与HA间的荧光猝灭以静态过程为主。LITRF猝灭法可快速有效原位研究PAHs与HA相互作用,有助于实现PAHs生态风险原位评估。     

原生垃圾和煤混烧时多环芳烃和二(噁)英的生成关联

为了评价多环芳烃作为二(口恶)英前驱物经由前驱物途径生成二(口恶)英反应途径的可能性,并找出能作为二(口恶)英在线监测的可能指示物,本文在小型管式炉上进行了原生垃圾和煤混合燃烧试验。结果表明,随着硫氯摩尔比的增加,生成的多环芳烃总量呈下降趋势,和二(口恶)英总量变化的趋势相同,多氯二苯并呋喃(PCDFs)的总量和多环芳烃总量的变化趋势比较相似,存在着一定的关联性。其中苯并[a]蒽(BaA)和PCDFs的关联性非常大,苯并[a]蒽有可能作为PCDF监测的可靠的指示物之一。