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1.
《Analytical letters》2012,45(7):545-560
Abstract

A quantitative analytical method has been developed for volatile pyridines in tobacco smoke using pyridine- 14C as an internal standard. Mainstream and sidestream smoke are trapped in 0.05 N sulfuric acid anti partitioned with chloroform. The acidic portion is then concentrated, adjusted to pH 3 and extracted with chloroform. Methanol and a trace of 2N sulfuric acid are added to this chloroform portion and the mixture is carefully concentrated.

A trace of sodium hydroxide is added and the final concentrate is analyzed by gas chromatography. Twenty-one volatile pyridines have been identified. The mainstream stroke of a popular. 85-mm U.S. cigarette without filter tip contained the following major pyridines: 33.4 μg pyridine, 12.3 μg α-picoline, 24.2 μg. β+γ-picoline, 7.6 μg 3-ethylpgridine, 5.9 μg: 4-ethylpyridine, and 23.3 μg 3,4-lutidine + 3-vinylpyridine. The sidestream smoke of this cigarette contained up to 28 times higher concentrations of pyridines.

Volatile pyridines were also determined in the mainstream smoke of other non-filter cigarettes, filter cigarettes, little cigars and, a non-tobacco cigarette. Of special interest were the much greater quantities of volatile pyridines in the mainstream and sidestream of cigars in comparison to those of cigarettes. The ratio of pyridines in sidestream to those in mainstream was 5 to 50 in large cigars. Selective filtration was observed with both cellulose acetate and charcoal filter tips. The analytical method resulted in reproducible values for pyridine, with an average recovery rate of more than 90%. In addition to pyridines, two pyrazines were also isolated from the smoke. Processed tobacco contained minute amounts of some volatile pyridines.  相似文献   

2.
高效液相色谱法测定卷烟烟气总粒相物中的烟碱   总被引:23,自引:0,他引:23  
谢笑天  郑萍  朱伟明  赵革玲 《分析化学》2000,28(9):1085-1087
采用反相高效液相色谱内标法测定卷烟烟气总粒相物中的烟碱含量,内标物为对氨基苯碘酸,方法的平行回收率为99.7%~100.1%,精密度好,操作简便、快速,可作为检测烟碱的一种可靠方法。  相似文献   

3.
成都市东郊(工业区)大气颗粒物及硫的分析   总被引:2,自引:0,他引:2  
通过分析2006年上半年成都市东郊大气中总悬浮颗粒物及其中硫化物的含量和形态并结合酸雨问题阐述了成都市大气颗粒物的污染状况,并在搜集有关资料及实验的基础上,对成都东郊TSP中的硫化物的主要形态和含量作了初步的探讨,同时分析了硫化物与酸雨的联系,得出了结论并提出了建议。  相似文献   

4.
雾过程对大气气溶胶PM10中多环芳烃粒径分布的影响   总被引:4,自引:0,他引:4  
在雾天气高发期间采集大气气溶胶PM10分级样品,测定了这些样品中的16种优控PAHs.结果表明:雾区近地层大气中PM2.1和PM9.0的平均质量浓度明显增加,雾过程改变了PM2.1的昼、夜浓度变化特征;雾前、雾中与雾后大气PM10中16种优控PAHs主要分布在比表面积大的细粒子上,平均有83.04%分布在Dp <2.1μm的范围,雾中1.1~2.1μm粒子的∑16PAHs浓度明显增加,Dp <0.65μm粒子的∑16PAHs浓度略有降低,说明雾过程对细粒子中∑16PAHs的浓度分布产生明显影响;雾前、雾中与雾后白天时间段,PM10分级粒子的∑16PAHs积聚模态分布出现较大差异,雾中积聚模态峰位置较雾前与雾后向较大粒径偏移;一次连续雾过程中,白天的∑16PAHs积聚模态峰位置随着雾的持续向大粒径方向偏移并停留在1.1~2.1μm;夜间的∑16PAHs积聚模态峰位置没有变化,均在1.1~2.1μm,说明PM10∑16PAHs的粒径分布受雾过程持续时间影响较大.  相似文献   

5.
固相微萃取(solid-phasemicroextraction,SPME)是20世纪90年代发展起来的一种样品前处理技术,与传统的液-液提取、液-固提取相比,SPME更适用于提取、浓缩液态或气态的挥发性和半挥发性物质,SPME技术可将采样、萃取、浓缩和样本引入集中于一个步骤完成,尤其随着自动SPME与GC-MS等联用技术的日益完善,使SPME技术优点得到更充分的发挥。  相似文献   

6.
The determination of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) in food and beverages sold in Turkey was carried out using liquid chromatography–tandem mass spectrometry (LC-MS/MS). A total of 123 samples of selected food and beverages such as fish, meat, offal, egg, cracker, chips, cake, chocolate, vegetable, milk and juice were examined. The highest PFOA concentrations were determined in cow meat (5.15 ng g?1), cow kidney (5.65 ng g?1), cow spleen (5.06 ng g?1) and chicken liver (5.02 ng g?1). The highest PFOS levels were found in horse mackerel (52.43 ng g?1), pike-perch (45.87 ng g?1), sardine (42.83 ng g?1) and black cod (41.33 ng g?1). Fish was found to be major source of the PFOS intake, while meat and offal were found to be major sources of the PFOA intake.  相似文献   

7.
采用熔融共混法制备了玻璃纤维增强聚对苯二甲酸乙二酯(PET-GF)/十溴二苯醚(DBDPO)/苯基膦酸铈(CeHPP)复合材料, 通过锥型量热仪(Cone)对复合材料的燃烧行为进行综合分析, 采用热失重-红外联用(TG-FTIR)分析了复合材料热降解过程中气体的释放量和主要成分, 并使用扫描电子显微镜(SEM)、 能量色散X射线光谱仪(EDX)和X射线光电子能谱(XPS)对复合材料燃烧后的残炭形貌、 残炭所含元素及含量等进行表征. 实验结果表明, 当CeHPP与DBDPO两者复配使用时, PET-GF/DBDPO/CeHPP复合材料的热解过程受到抑制, 凝聚相的燃烧减缓, 材料总的热分解量降低, 烟气释放量明显减小. 这主要是由于CeHPP在燃烧过程中形成了连续致密的残炭, 分布于基材和玻璃纤维表面, 将部分DBDPO及其分解产物滞留于凝聚相, 从而实现了气相-凝聚相双重阻燃作用, 有效阻隔了挥发性气体产物的释放.  相似文献   

8.
Nowadays, little technology exists that can monitor various water sources quickly and at a reasonable cost. The ultra-sensitive, fully automated and robust biosensor River Analyser (RIANA) is capable of detecting multiple organic targets rapidly and simultaneously at a heterogeneous assay format (solid phase: bulk optical glass transducers). Commercialization of such a biosensor requires the availability of commercial high-affinity recognition elements (e.g. antibodies) and suitable commercial haptens (modified target molecules) for surface chemistry. Therfore, testosterone was chosen as model analyte, which is also a task of common analytical methods like gas chromatography-mass spectrometry (GC-MS), because they have to struggle with detecting sub-nanogram per liter levels in environmental samples. The reflectometric interference spectroscopy (RIfS) was used to characterize the commercially available immunochemistry resulting in a high-affinity constant of 2.6 ± 0.3 × 109 mol−1 for the unlabeled antibody. After the labeling procedure, necessary for the TIRF-based biosensor, a mean affinity constant of 1.2 × 109 mol−1 was calculated out of RIfS (1.4 ± 0.4 × 109 mol−1) and TIRF (1.0 ± 0.3 × 109 mol−1) measurements.Thereafter, the TIRF-based biosensor setup was used to determine the steroidal hormone testosterone at real world samples without sample pre-treatment or sample pre-concentration. Results are shown for rapid and ultra-sensitive analyses of testosterone in aqueous samples with at a remarkable limit of detection (LOD) of 0.2 ng L−1. All real world samples, even those containing testosterone in the sub-nanogram per liter range (e.g. 0.9 ng L−1), could be determined with recovery rates between 70 and 120%. Therefore, the sensor system is perfectly suited to serve as a low-cost system for surveillance and early warning in environmental analysis in addition to the common analytical methods. For the first time, commercially available immunochemistry was fully characterized using a label-free detection method (RIfS) and successfully incorporated into a TIRF-based biosensor setup (RIANA) for reliable sub-nanogram per liter detection of testosterone in aqueous environmental samples.  相似文献   

9.
The synthesis of branched poly(ethylene glycol) (PEG) derivatives, namely star PEG and dendronized PEG, can be challenging and their purity can be difficult to ascertain using traditional techniques, such as NMR and GPC. Herein, the detailed characterization of these branched PEGs using MALDI-ToF MS was investigated in order to confirm their structural purity. In this light, mass spectrometry offers a number of advantages for polymer characterization, including the ability to get detailed structural data, such as end group masses, from microgram-scale samples. In addition, the ability to rapidly acquire data from crude reaction aliquots makes MALDI-ToF MS ideal for monitoring end group transformations.  相似文献   

10.
Two new HPTLC methods for quantification of isopropyl-9H-thioxanthen-9-one (ITX) in milk, yoghurt and fat samples have been developed. Extraction of ITX from milk and yoghurt was performed with a mixture of cyclohexane and ethyl acetate by employment of accelerated solvent extraction (ASE). For soy bean oil and margarine, a simple partitioning of ITX into acetonitrile was used. ITX and 2,4-diethyl-9H-thioxanthen-9-one (DTX) used as internal standard have been separated on silica gel 60 HPTLC plates with a mixture of toluene and n-hexane (4:1, v/v) and on RP18 HPTLC plates with a mixture of acetonitrile and water (9:1, v/v). Development was performed anti-parallel from both plate sides leading to a throughput of 36 separations in 7 min. Fluorescence measurement at 254/>400 nm was used for quantification. Limits of detection (S/N of 3) have been established to be 64 pg for ITX and DTX on both types of HPTLC plates. In fatty matrix (spiked butter) LOD of ITX was determined to be 1 μg kg−1. In the working range monitored (20–200 μg kg−1) polynomial regression of ITX showed a relative standard deviation (sdv) of ±1.51 % (r=0.99981). Starting with the limit of quantification the response was linear (sdv=±2.18 %, r=0.99893). Regarding repeatability (n=9) a coefficient of variation (CV) of 1.1 % was obtained for ITX at 32 ng on silica gel plates and of 2.9 % on reversed-phase plates. Repeatabilities (n=4) of ITX determination at 20, 50 and 100 μg kg−1 in milk, yoghurt, soybean oil and margarine showed CVs between ±1.0 and 6.4 %. The results prove that modern planar chromatography is a rapid and cost-efficient alternative method to quantify ITX in milk-based or fatty matrices. Only positive results are confirmed by online ESI/MS in the SIM mode (LOQ 128 pg) and by DART/MS involving a minimal employment of the MS device, which is a further advantage of HPTLC. Overall mean recovery rates of ITX at 20 or 50 and 100 μg kg−1 (n=8) were 41 % for milk, 70 % for yoghurt, 6 % for margarine and 12 % for soy bean oil. However, with the internal standard correction recoveries were about 130 % for milk and yoghurt and 70 and 97 % for margarine and soy bean oil, respectively.   相似文献   

11.
研究了鮰鱼体内六溴环十二烷(HBCDs)异构体的浓度分布与生物累积特征。首先采用基质固相分散(MSPD)法,同位素稀释定量,高效液相色谱-电喷雾串联质谱(HPLC-ESI-MS/MS)检测技术,建立了渔业饲料和鱼体中α-HBCD、β-HBCD和γ-HBCD的分析方法。该法对α-HBCD、β-HBCD、γ-HBCD的回收率分别为80.7%~110.5%、80.1%~109.0%、86.9%~104.5%,其检出限分别为0.002、0.002、0.001 ng/g。采用所建立的方法对25个渔业饲料样品和30个鱼样品进行分析,三种异构体在渔业饲料中的检出率均为16%,在鱼产品中的检出率分别为10%、6.67%和10%。鱼中HBCDs含量与渔业饲料中HBCDs含量的比值(生物累积因子)的结果为:α-HBCD,0.78;β-HBCD,0.45;γ-HBCD,1.08。对HBCDs在配对的渔业饲料与鱼中的相关关系进行了研究。  相似文献   

12.
Investigations of inorganic oligomers are important in both chemistry and physiology. In this contribution, we propose a laser induced light scattering imaging (LSI) and a total internal reflected light scattering imaging (TIR-LSI) technique, and apply them to characterize the interactions of inorganic oligomers with biopolymer in aqueous phase and at liquid/liquid interface, respectively. In aqueous medium, synthetic chromium(III) hydrolytic oligomers (CrHO) react with DNA, and the resultant binary could be extracted into the H2O/CCl4 interface in the presence of triocyctyl phosphine oxide (TOPO), forming a DNA-CrHO-TOPO ternary amphipathic complex at the interface with the associate constant of 1.32 × 103 mol−1 dm4 for a given 1.0 × 10−4 mol l−1 TOPO. Under the excitation of a 441-nm He-Cd laser light beam, the resultant light scattering and total internal reflected light scattering (TIR-LS) signals of the formed binary in aqueous phase and ternary at liquid/liquid interface could be easily captured using a common microscope coupled with a CCD camera. By digitally analyzing the CCD captures, we demonstrate that aggregations of the CrHO-DNA binary in aqueous phase and DNA-CrHO-TOPO ternary at liquid/liquid interface have occurred, respectively.  相似文献   

13.
Ricin, a plant‐derived toxin extracted from the seeds of Ricinus communis (castor bean plant), is one of the most toxic proteins known. Ricin's high toxicity, widespread availability, and ease of its extraction make it a potential agent for bioterrorist attacks. Most ricin detection methods are based on immunoassays. These methods may suffer from low efficiency in matrices containing interfering substances, or from false positive results due to antibody cross reactivity, with highly homologous proteins. In this study, we have developed a simple, rapid, sensitive, and selective mass spectrometry assay, for the identification of ricin in complex environmental samples. This assay involves three main stages: (a) Ricin affinity capture by commercial lactamyl‐agarose (LA) beads. (b) Tryptic digestion. (c) LC‐MS/MS (MRM) analysis of tryptic fragments. The assay was validated using 60 diverse environmental samples such as soil, asphalt, and vegetation, taken from various geographic regions. The assay's selectivity was established in the presence of high concentrations of competing lectin interferences. Based on our findings, we have defined strict criteria for unambiguous identification of ricin. Our novel method, which combines affinity capture beads followed by MRM‐based analysis, enabled the identification of 1 ppb ricin spiked into complex environmental matrices. This methodology has the potential to be extended for the identification of ricin in body fluids from individuals exposed (deliberately or accidentally) to the toxin, contaminated food or for the detection of the entire family of RIP‐II toxins, by applying multiplex format.  相似文献   

14.
The complexes of 3-carboxy-4-hydroxybenzenesulfonic acid (5-sulfosalicylic acid, H3SSA) with rubidium(I), caesium(I) and lead(II) have been synthesized and characterized using single-crystal X-ray methods at 130 K. The rubidium(I) complex 1, [Rb3(H2SSA)(HSSA)(H2O)4]n, is an unstable hydrate variant of a previously described complex [Rb(H2SSA)(H2O)]n, and comprises three independent and different seven-coordinate metal polyhedra interlinked through oxygen donors of the sulfonate, carboxylate and phenolate groups of the 5-sulfosalicylate ligands (one of which is dianionic, the other monoanionic), and one bridging water, giving a three-dimensional hydrogen-bonded framework polymer structure. The anhydrous caesium(I) complex 2 [Cs(H2SSA)]n, which has been previously described in a room-temperature determination, has a three-dimensional framework polymer structure based on an irregular Cs–O9 repeating unit. Complex 3 with lead(II), [Pb(H2SSA)2(H2O)]n, forms helical step-polymer ribbon substructures having an irregular Pb–O7 coordination centre comprising a single monodentate water and six sulfonate-O donors bridging three separate metals. The carboxylic acid and phenol substituent groups of the 5-sulfosalicylate ligand link the ribbons peripherally through hydrogen bonds, giving a three-dimensional layered framework polymer structure.  相似文献   

15.
Poly(vinyl alcohol) (PVA) (polymer A) and poly(N-vinylpyrrolidone) (PVP) (polymer B) are known to form a thermodynamically miscible pair. In the present study the conclusion on miscibility of PVA/PVP solid blends, confirmed qualitatively (DMTA, FTIR) and quantitatively (DSC, χAB = − 0.69 at 503 K) is compared with the miscibility investigations of PVA/PVP solution blends by the technique of dilute solution viscometry. The miscibility of the ternary (polymer A/ polymer B/ solvent) system is estimated on the basis of experimental and ideal values of the viscosity parameters k, b and [η]. It is found that the conclusions on miscibility or nonmiscibility drawn from viscosity measurements in dilute solution blends depend: (i) on the applied extrapolation method used for the determination of the viscosity interaction parameters, (ii) on the assumed definition of the ideal values and (iii) on the thermodynamic quality of the solvent, which in the case of PVA depends on its degree of hydrolysis. Hence, viscometric investigations of dilute PVA/PVP solution blends have revealed that viscometry, widely used in the literature for estimation of polymer-polymer miscibility can not be recommended as a sole method to presume the miscibility of a polymer pair.  相似文献   

16.
The complexation of Pb2+, Tl+ and Cd2+ cationsby 18-crown-6 was studied in water/propanol (H2O/PrOH),water/acetonitrile (H2O/AN) and water/dimethylformamide(H2O/DMF) binary systems at 20 °C using squarewave polarography (SWP) and differential pulse polarography (DPP).It was confirmed that the stoichiometry of each of the complexes formed between 18C6 and the respective cations is 1 : 1. The formation constants of the complexes were found to increase with increasing concentration of the non-aqueous solvent. In all cases, a stability order of Pb2+ > Tl+ > Cd2+ was observed. In general,the stabilities of individual complexes were found to decrease as the binary solvent mixture varied from H2O/AN to H2O/PrOH to H2O/DMF.  相似文献   

17.
Chiral Schiff base complexes containing azo-groups, bis(N-R-1-cyclohexylethyl-4-phenyldiazenylsalicydenaminato) nickel(II), copper(II) and zinc(II) complexes, and without azo-groups, bis(N-R-1-cyclohexylethyl-3,5-dichlorosalicydenaminato) nickel(II), copper(II) and zinc(II) complexes, affording a distorted square planar trans-[MN2O2] coordination geometry were prepared. Organic/inorganic hybrid materials in polymethylmethacrylate (PMMA) spincoat films of the complexes (both the azobenzene (AZ) containing type and the latter complexes of the AZ separated type) were assembled for a comparison of polarized UV light induced molecular arrangement caused by the Weigert effect. Investigation of the parameters for the optical anisotropy of the metal complexes as well as AZ suggested that the degree of increasing optical anisotropy of the containing type was higher than that of the separated type based on π-π (of which a characteristic band appeared around 380 nm) and n-π bands of polarized absorption electronic spectra. In the AZ containing type, the rigid nickel(II) or zinc(II) complexes easily increase the optical anisotropy compared to the flexible copper(II) complexes. In the AZ separated type, interestingly, enhancement of some CD bands suggests the role of chiral dopants of some complexes without azo-groups for AZ.  相似文献   

18.
湖州表层土壤稀土元素含量及分布特征   总被引:2,自引:0,他引:2  
为了研究湖州表层土壤样品中稀土元素的分布特征,利用ICP-MS测定了土壤中稀土元素的含量。结果表明湖州表层土壤中稀土元素含量的大小顺序为:Ce>La>Nd>Pr>Sm>Gd>Dy>Yb>Er>Eu>Ho>Tb>Tm>Lu,遵循Oddo-Harkins法则。湖州表层土壤中稀土元素的分量均值和总量均值皆高于全国水平,稀土元素存在显著的分馏现象,轻稀土元素明显富集。表层土壤中Ce和Eu都有部分亏损。  相似文献   

19.
A sensitive, rapid and easy analytical method was validated for the determination of quinoid niclosamide (LDS) molluscicide in water, rice and soil using a QuEChERS extraction procedure and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection. The LDS was extracted by using acetonitrile and then cleaned up by using dispersive solid-phase extraction with florisil and C18 sorbents. The determination of the target compound was achieved in less than 3 min using an electrospray ionisation source in negative mode. The overall average recoveries for this method in water, rice and soil matrix at three fortified levels ranged from 82.54 to 99.9%, with relative standard deviations in the range of 1.51 to 4.86% (n = 5). The calculated limits of detection were lower than 0.1 µg kg?1 and quantification was 5 µg kg?1; these values were much lower than the maximum residue levels established by the Australian standard (0.01 mg kg?1). The results of the method validation confirmed that this proposed method is convenient and reliable for the determination of LDS molluscicide in water, rice and soil samples.  相似文献   

20.
介绍了用离子色谱法测定大气总悬浮颗粒物(TSP)中的F~-,Cl~-,NO~-_3及SO~2-_4。对过氯乙烯采样滤膜用去离子水(DIH_2O)作为提取液进行超声波提取。方法的平均回收率分别为F~-98.7%,Cl~-103%,NO~-_3101%及SO~2-_499.8%,相对标准偏差为F~-0.29%,Cl~-0.32%,NO~-_30.30%及SO~2-_40.25%。  相似文献   

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