快速溶剂萃取-气相色谱-质谱法同时测定土壤中多环芳烃、六六六和滴滴涕

建立快速溶剂萃取-气相色谱-质谱法同时测定土壤中多环芳烃、六六六和滴滴涕。优化了提取溶剂和洗脱溶剂,采用加速溶剂萃取法处理土壤样品,萃取溶剂为二氯甲烷-正己烷(1∶1)。提取液用氮吹仪浓缩、硅酸镁固相萃取小柱净化,用二氯甲烷-正己烷(3∶7)混合溶剂对固相萃取小柱进行活化和洗脱,流出液净化后氮吹浓缩至1 mL,利用气相色谱-质谱内标法进行分析定量。16种多环芳烃、8种有机氯农药及3种替代物在5.0～500μg/L范围内线性良好,方法检出限为0.000 55～0.000 77 mg/kg,加标回收率为68.2%～112.7%,相对标准偏差为4.3%～10.1%(n=5)。该方法可用于同时测定土壤中多环芳烃、六六六、滴滴涕的含量。     

气相色谱-质谱法测定塑料玩具中多环芳烃

提出了气相色谱-质谱法测定塑料玩具中16种多环芳烃(PAH′s)含量的方法。样品经正己烷超声提取30min后,40℃水浴氮气吹干。用水、甲醇和正己烷-二氯甲烷(3+2)混合溶剂各5mL溶解残渣,过C18固相萃取柱净化,用正己烷-二氯甲烷(3+2)混合溶液洗脱,所得洗脱液过HP-5MS色谱柱分离,电子轰击离子源检测。16种多环芳烃的质量浓度在0.2～4.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.002～0.021mg·kg-1之间。以聚丙乙烯、聚乙烯、聚氯乙烯或丙烯腈-丁二烯-苯乙烯共聚物等4种材质的塑料玩具为基体,进行加标回收试验,回收率在79.6%～95.2%之间。     

加速溶剂-固相萃取-高效液相色谱法测定土壤及蚯蚓样品中多环芳烃

研究了加速溶剂萃取( ASE)、固相萃取柱净化( SPE)、高效液相色谱( HPLC)联合( ASE-SPE-HPLC)测定土壤及蚯蚓样品中7种多环芳烃(PAHs)的分析方法,确定了以正己烷-丙酮(4∶1, V/V)作为萃取剂,用ASE对土壤及蚯蚓进行萃取,提取液经SPE柱净化(土壤样品用硅胶柱净化,蚯蚓样品用 Al2 O3-硅胶柱净化),正己烷-二氯甲烷(9∶1, V/V)进行洗脱,洗脱体积为10 mL,旋转浓缩蒸干后,乙腈定容,过0.22μm有机滤膜,最后用HPLC对提取液中7种PAHs进行定量的分析方法。土壤样品方法回收率在83.5%~110.2%之间,相对标准偏差为1.0%~4.6%;蚯蚓样品回收率在81.2%~97.1%之间,相对标准偏差为1.6%~4.2%。方法检出限为0.15~0.85μg/kg,且重现性好。可满足样品分析的质量控制要求,表明本分析方法具有良好的准确性与可靠性。     

超声波萃取-SPE净化-双柱双检测器测定土壤和沉积物中的20种有机氯

建立了超声波萃取-SPE硅胶小柱净化-双柱双检测器气相色谱法测定土壤和沉积物中20种有机氯农药的方法。样品中添加高纯铜粉除硫,二氯甲烷超声萃取9 min,使用SPE硅胶小柱,9 mL丙酮:正己烷(1:9)洗脱净化。采用单进样口,双色谱柱双μ-ECD同时分离测定。土壤和沉积物样品中的方法检出限为0.001 mg/kg,平均回收率为73.17%～112.5%,相对标准偏差为0.33%～16%。     

固相萃取-气相色谱-质谱法测定石油烃污染土壤中半挥发性有机物

取被石油烃污染的土壤样品经快速萃取仪萃取后,用经活化的Silica硅胶小柱进行净化,用正己烷淋洗,弃去前1.0 mL正己烷淋洗液,再用体积比为1:19的丙酮-正己烷混合溶剂洗脱。洗脱液氮吹浓缩至小于1.0 mL,加内标物并用正己烷定容至1.0 mL,过滤。滤液中半挥发性有机物(SVOC)经气相色谱分离后采用电子轰击离子源、全扫描和选择离子监测模式进行质谱分析,采用内标法定量。方法比较了不同固相萃取小柱、正己烷的用量、洗脱剂的种类等条件对样品净化效果的影响,在优化的试验条件下,SVOC的线性范围均为1～20 mg·L~(-1),检出限为0.06～0.30 mg·kg~(-1)。按标准加入法在3个浓度水平进行回收试验,在低加标水平下,测得回收率较高,为35.8%～145%,测定值的相对标准偏差(n=6)为0.60%～15%。     

微波辅助萃取/气相色谱-质谱法同时测定纸质食品接触材料中18种多环芳烃

建立了同时测定纸质食品接触材料中18种禁用多环芳烃的气相色谱-质谱/选择离子监测方法。以二氯甲烷-正己烷(1∶1)为提取溶剂,在90℃下微波辅助萃取纸质食品接触材料中的多环芳烃,提取液经二甲亚砜萃取、环己烷反萃取、硅胶固相萃取柱净化后,进行气相色谱-质谱/选择离子监测分析,外标法定量。各组分的检出限为0.1~1.0μg/kg,相关系数均大于0.997,加标回收率为56.3%~95.4%,相对标准偏差均小于7%。该方法简便快捷、灵敏度高、定性定量准确,适用于纸质食品接触材料中多环芳烃的同时测定。     

固相萃取法测定水中短链氯化石蜡

建立了固相萃取法结合气相色谱-低分辨率电子捕获负化学源质谱(GC/ECNI-MS)测定水样中短链氯化石蜡(SCCPs)的方法。选取了4种不同填料的商品化固相萃取柱,对淋洗溶剂、洗脱溶剂、洗脱溶剂体积等实验参数进行了优化。经过优化的实验条件为:Agilent Bond Elut-C_(18)固相萃取柱分别用3 mL正己烷、3 mL甲醇、3 mL Milli-Q纯水预淋洗并活化,上样后,用3 mL 10%(V/V)甲醇淋洗,3 mL正己烷-二氯甲烷(1∶1,V/V)洗脱。本方法的检出限和定量限分别为18 ng/L和60 ng/L。1μg/L加标水平下回收率为90%~130%,相对标准偏差低于±10%。采用本方法对北京20个水体样品中的短链氯化石蜡水平进行了测定,浓度范围为LOD~682 ng/L,在检测到SCCPs的18个样品中SCCPs的均值为216 ng/L。     

气相色谱-离子阱串联质谱法测定湖泊沉积物中16种多环芳烃

应用气相色谱与离子阱串联质谱(GC-MS/MS)联用技术同时测定了湖泊沉积物中16种多环芳烃(PAH′s)。将干燥的沉积物试样用二氯甲烷-丙酮(1+1)混合溶剂提取,加入一定量的D10-芘作为回收率指示物。将浓缩为1 mL的萃取液通过硅胶/氧化铝层析柱,并先后用正己烷、二氯甲烷-正己烷(3+7)混合溶剂及甲醇淋洗层析柱,使浓缩液中的饱和烃、芳烃和非芳烃分离。将含有芳烃的淋出液收集并浓缩至1 mL供GC-MS/MS分析。加入定量的D12苯并苝作为内标,在所选定的条件下,上述16种PAH′s在40 min内达到完全分离,并进行串联质谱测定。16种PAH的检出限(3S/N)在0.03μg.L-1(萘)至0.34μg.L-1[二苯并(a,h)蒽]之间。测得方法的回收率在70%~90%之间。     

固相萃取-气相色谱-质谱法测定地下水中多环芳烃

提出了固相萃取-气相色谱-质谱法测定地下水中16种多环芳烃的方法。样品经ENVIC18固相萃取柱富集,依次用丙酮5 mL和二氯甲烷10 mL将16种多环芳烃从固相萃取柱上洗脱,用K-D浓缩器浓缩后,供气相色谱-质谱仪测定。纯水或自来水经固相萃取处理后,再用于配制标准溶液并绘制标准曲线。16种多环芳烃的检出限(3S/N)均小于2.0 ng.L-1。用该法分析地下水样品,所得结果的相对标准偏差(n=7)小于14.0%,加标回收率在84.3%~112.3%之间。     

高效液相色谱法测定橡胶及其制品中16种多环芳烃

经粉碎的橡胶样品用正已烷及丙酮(1+1)的混合溶剂萃取,所得萃取液蒸至近干后加入正己烷2 mL溶解残渣,将溶液经硅胶固相萃取柱分离并净化,吸附于柱上的多环芳烃用由正己烷及二氯甲烷(3+2)组成的淋洗液解吸,洗出液蒸至近干加入一定量的内标溶液使之溶解并用高效液相色谱法测定.选用LC-PAH色谱柱作固定相,用乙腈和水以不同比例混合的溶液作为流动相进行梯度淋洗,紫外检测器的测定波长为210 nm,以苝-d12作为内标进行定量测定,在优化的试验条件下16种多环芳烃可有效分离并测定.研究结果表明:16种多环芳烃的检出限(3S/N)、平均回收率及测定值的相对标准偏差(n=7)依次在0.05～0.10 mg·L-1,65.1%～101.7%及1.8%～7.3%之间.     

计算共振能的一个新的经验方法

本文提出了一个很简单的计算共振能(RE)的方法。对苯系芳烃,可用下式计算: RE(cV)=0.215(0.89N_0+0.75N_1+0.36N_2)式中,N_0是顶点度为3的碳原子数,N_1是顶点度为2但被两个顶点度为2的原子所连结的碳原子数,N_2是顶点度为2但被一个顶点度为2和另一个顶点度为3的原子所连结的碳原子数。此或略加修正也可用于计算含四元环共轭烃、半苯型烃和奥系化合物等共轭烃的共振能。     

State-of-the-art of gas chromatography-based methods for analysis of anthropogenic volatile organic compounds in estuarine waters,illustrated with the river Scheldt as an example

This review focuses on a number of key procedural steps in the analysis of volatile organic compounds (VOCs) in estuarine waters. The most critical step, from an analytical point of view, is sample preparation. So far, only purge-and-trap and, to some extent, membrane inlet mass spectrometry have successfully been applied in estuarine monitoring of VOCs. The advantages and disadvantages of both techniques are discussed and novel developments are reviewed. Other key elements in VOC analysis and assessment include quality assurance (QA), quality control (QC) and statistical data analysis. This paper gives a brief overview of QA/QC measures of interest in the estuarine monitoring exercise, and provides guidelines for adequate statistical treatment of environmental data. Finally, field measurements of VOCs in estuarine waters are reviewed. Concentrations are reported, and distribution patterns, sources and time-trends are discussed. In addition to literature data, results of a 3-year monitoring survey (May 1998–November 2000) in the Scheldt estuary are presented.     

On some problems in the theorems of alternant hydrocarbons

A number of theorems of alternant hydrocarbons presented by Dewar are proved to be wrong. A statement of the related theorem instead of Dewar's is presented.     

Ground state properties of some nonbenzenoid hydrocarbons

Ground state properties including - and -bond energies, resonance energy, and heats of atomization of some nonbenzenoid hydrocarbons have been studied using the method of Dewar and Harget and compared with results obtained by the Dewar-de Llano method. It is seen that the Dewar-Harget method is less effective in correlating the chemical properties.     

Recent Studies on the Decomposition of n-Hexane and Toluene in RF Thermal Plasma

Thermal decomposition of volatile organic compounds (VOCs) such as n-hexane and toluene has been studied in an inductively coupled thermal plasma reactor, at atmospheric pressure, in neutral and oxidative conditions, respectively. Thermodynamic calculations were performed for predicting the product distribution due to thermal decomposition. Based on these calculations formation of the products observed in the gas phase and in the extract of soot could be interpreted. In neutral conditions formation of soot and PAH was detected to different extent for the different models. The presence of oxygen in the plasma reactor depresses both soot and PAH formation. GC-MS analyses of the gaseous products and the extract of the soot, respectively, refer to as complex decomposition and recombination mechanism in given conditions.     

沉积物和原油中常见含氧化合物的分离分析

将沉积物抽提物和原油中复杂的非烃组成分离为酸性、中性I和中性Ⅱ3个馏分。各馏分经GC／MS分析证实羟酸和极性较大的多元醇和酮进入酸性馏分,一元酮、酯和直接一元醇进入中性馏分I,而甾醇类化合物进入中性瘤分Ⅱ。各类化合物分段清晰,没有同一化合物在不同馏分中出现的现象,且分离过程中各化合物的比例基本保持不变。本文选用地质体中今未见析出的二十二烯酸,5α（H）－雄甾－17－酮和5α（H）－3β－醇分别作为各馏分的内标化合物,定量效果好,并首次为甾醇类化合物找到了较理想的内标物。本方法经近百个样品的分离分析证实效果良好。     

HPLC determination of the aromatic fraction of gasoline

Summary This work reports a rapid and easy procedure for the analysis of the aromatic fraction in gasoline. No sample pretreatment is required, since the gasoline is diluted in methanol and directly injected into a liquid chromatograph. A spectrophotometer detector and a spectrofluorimeter detector are used in series. The procedure has been applied to a large number of Italian and European refined gasoline samples.Dedicated to Prof. Dr. A. Liberti on the occasion of his 70th birthday.     

Separation of the mineral oil aromatic hydrocarbons of three and more aromatic rings from those of one or two aromatic rings

An analytical method was developed for the quantitation of the mineral oil aromatic hydrocarbons in cosmetic raw materials separating those of one or two aromatic rings from those of three and more aromatic rings. Normal phase high performance liquid chromatography was used with donor‐acceptor complex chromatography. The composition of both fractions and the quantities of respective compounds were determined by comprehensive two dimensional gas chromatography with time of flight mass spectrometry and by liquid chromatography coupled to gas chromatography with flame ionization detection.     

Simultaneous determination of volatile aromatic and halogenated hydrocarbons in water and soil by dual-channel ECD/PID equilibrium headspace analysis

Volatile aromatic and halogenated hydrocarbons are determined in water and soil samples by equilibrium headspace gas chromatography. Simultaneous analysis is carried out in a dual column/dual detector arrangement with ECD and PID. Their determination in contaminated soil is performed with the same instrumental configuration. However, in contrast to water analysis, an increased sample temperature was found necessary for highly adsorptive soil specimens. At sample temperatures of 95 °C, recoveries near 100% have been found. Both adsorption and desorption processes were found to be strongly time-dependent.     

Correlation equations for prediction of gas chromatographic separation of hydrocarbons on squalane

Summary The retention index of several hydrocarbon classes on squalane was found to be predictable (within two index units) with help of a physico-chemical index and a correction-structural number. A large number of structural elements were examined by means of correlation analysis and regression equations were obtained for calculation of the structural number. The multinomial regression equations were simplified by combining in one factor the important structural elements. A set of a limited number of selected representatives for every hydrocarbon class was found to give reliable estimations for the regression coefficient equations.