广西产马尾松与湿地松针叶精油化学成分的比较

用水蒸气蒸馏法从广西产马尾松和湿地松的针叶中提取精油,探索了松针投料量和提取时间对产油率的影响,确定了最佳工艺条件为：松针投料量700 g,提取时间5 h。在此最佳条件下马尾松和湿地松针叶的产油率分别为0.45%和0.19%。用气相色谱（GC）和气相色谱-质谱（GC-MS）等方法分别对两树种的针叶精油进行了定量和定性分析,从马尾松针叶精油中分离出64种化学成分,鉴定了其中的20种成分,占挥发油总量的98.59%;从湿地松针叶精油中分离出73种化学成分,鉴定了其中的29种成分,占挥发油总量的94.23%。两树种针叶精油的主要化学成分大致相同,但在含量上有较大差别。马尾松针叶精油中α-蒎烯的含量约为湿地松的2.6倍,但其β-蒎烯含量低于后者。单萜和倍半萜是构成马尾松和湿地松针叶精油的主要成分。     

瓯柑石油醚提取物的GC-MS分析

为了研究瓯柑的挥发性成分和脂溶性成分, 采用GC-MS分析法进行分离鉴定, 并用面积归一法确定各成分的质量分数. 从瓯柑果肉石油醚提取物中分离鉴定出11种成分, 占总提取物的97.43%, 其主要成分为(Z, Z)-9, 12-十八碳二烯酸(37.46%)、γ-谷甾醇(22.91%);从瓯柑皮石油醚提取物中分离鉴定出10种成分, 占总提取物的99.79%, 其主要成分为柠檬烯(86.39%).     

Cation-exchange separation of metals in dimethyl sulphoxide-aqueous hydrochloric acid media

The behaviour of bismuth, cadmium, copper, lead, silver, tin and zinc on a cation-exchange resin in a solvent system consisting of dimethyl sulphoxide, hydrochloric acid and water was studied. The distribution coefficients of these metal ions between liquid and resin were determined as functions of the concentration of dimethyl sulphoxide and of hydrochloric acid. On the basis of the distribution coefficients found, predictions were made as to the possibilities of separating these metals from mixtures. Such separations were confirmed experimentally for bismuth from lead, bismuth from copper, zinc from lead, lead from cadmium, silver from copper, silver from lead, lead from cadmium from zinc, bismuth from lead from zinc, and bismuth from zinc from copper.     

Elemental contents in hair of children from Zanzibar in Tanzania as bio-indicator of their nutritional status

Nutritional status and toxic elements body burden were evaluated in hair of children living in Zanzibar. 18 samples were collected from Zanzibar town and 19 samples from Nungwi village, which is approximately 64 km from Zanzibar town. The analysis was carried out using instrumental neutron activation analysis (INAA). The concentration ranges obtained in this study overlap with the published elemental values of healthy children of the same age group. The concentration levels of K, Zn, Cu, As and Co in hair of children from Zanzibar town were higher than from Nungwi whereas levels of Mn, Br and Sr were lower.     

GC-MS方法分析杨梅果实精油中香气成分

采用气相色谱一质谱联用技术分析鉴定了木叶、东魁及黑炭3种新鲜杨梅果实精油样品的化学成分,并对三者成分进行对比分析.木叶梅果实精油中鉴定出55个化合物,以单萜类成分为主;东魁梅果精油中鉴定出49个化合物,以倍半萜烯和烷烃类成分为主;黑炭梅果精油中鉴定出化合物48种,以倍半萜烯和烷烃类成分为主.木叶杨梅中富含单萜而缺少倍半萜烯,这可能是其香气浓且易腐烂原因.     

GC-MS analysis of aroma of Medemia argun (mama-n-khanen or mama-n-xanin), an ancient Egyptian fruit palm

The fruits of the edible and medicinal Egyptian palm, Medemia argun, were collected from Aswan in Egypt and the essential oil (EO) from fruits and headspace (HS) of the seeds and fleshy mesocarps were analyzed by GC and GC-MS. Results obtained by GC-MS analysis indicated a high variability in the oil and in the headspace from seeds and mesocarps. Sesquiterpene derivatives were the main group of volatiles in the EO from fruits and in the HS from seeds (45.0 and 64.0%, respectively), while oxygenated hydrocarbon derivatives were the main constituents in the HS obtained from fleshy mesocarps (96.5%). The different chemical composition of the headspace obtained from the seeds and mesocarps of M. argun can be correlated with the different roles that the different constituents play in the prevention of dehydration of the fruits in the desert region from where the plant was collected.     

Variability of volatile constituents in Artemisia maritima in western Himalaya

Chemical composition of the essential oil of Artemisia maritima, collected from three different high altitude locations in western Himalaya was studied by gas-chromatography mass spectrometry. Twenty-five constituents were identified in the oil distilled from the sample from Pooh, of which 1,8-cineole (23.8%) and chrysanthenone (17.54%) were the major constituents. Twenty volatile constituents were identified from the sample collected from Rhongtong pass, of which chrysanthenone (38.1%) and 1,8-cineole (37.3%) were the major constituents. In the oil distilled from the sample collected from Lahaul-Spiti 28 constituents were identified, of which 1,8-cineole (44.22%), camphor (9.16%) and borneol (10.94%) were the major constituents. In this sample chrysanthenone was present in very low percentage.     

Collision-induced fragmentation of negative ions from N-linked glycans derivatized with 2-aminobenzoic acid

N-Linked glycans from bovine ribonuclease B, chicken ovalbumin, bovine fetuin, porcine thyroglobulin and human alpha(1)-acid glycoprotein were derivatized with 2-aminobenzoic acid by reductive amination and their tandem mass spectra were recorded by negative ion electrospray ionization with a quadrupole time-of-flight mass spectrometer. Derivatives were also prepared from 2-amino-5-methyl- and 2-amino-4,5-dimethoxybenzoic acid in order to confirm the identity of fragment ions containing the reducing terminus. Major fragments from the [M - H](-) ions from the neutral glycans retained the derivative (Y-type cleavages) and provided information on sequence and branching. Other major fragments were products of A-type cross-ring cleavages giving information on antenna structure. Singly doubly and triply charged ions were formed from sialylated glycans. They produced major fragments by loss of sialic acid and a series of singly charged ions that were similar to those from the neutral analogues. Doubly charge ions were also produced by the neutral glycans and were fragmented to form product ions with one and two charges. Again, the fragment ions with a single charge were similar to those from the singly charged parents, but branching information was less obvious because of the occurrence of more abundant ions produced by multiple cleavages. Detection limits were around 200 fmol (3 : 1 signal-to-noise ratio).     

Generalized and facile synthesis of semiconducting metal sulfide nanocrystals

We report on the synthesis of semiconductor nanocrystals of PbS, ZnS, CdS, and MnS through a facile and inexpensive synthetic process. Metal-oleylamine complexes, which were obtained from the reaction of metal chloride and oleylamine, were mixed with sulfur. The reaction mixture was heated under appropriate experimental conditions to produce metal sulfide nanocrystals. Uniform cube-shaped PbS nanocrystals with particle sizes of 6, 8, 9, and 13 nm were synthesized. The particle size was controlled by changing the relative amount of PbCl(2) and sulfur. Uniform 11 nm sized spherical ZnS nanocrystals were synthesized from the reaction of zinc chloride and sulfur, followed by one cycle of size-selective precipitation. CdS nanocrystals that consist of rods, bipods, and tripods were synthesized from a reaction mixture containing a 1:6 molar ratio of cadmium to sulfur. Spherical CdS nanocrystals (5.1 nm sized) were obtained from a reaction mixture with a cadmium to sulfur molar ratio of 2:1. MnS nanocrystals with various sizes and shapes were synthesized from the reaction of MnCl(2) and sulfur in oleylamine. Rod-shaped MnS nanocrystals with an average size of 20 nm (thickness) x 37 nm (length) were synthesized from a 1:1 molar ratio of MnCl(2) and sulfur at 240 degrees C. Novel bullet-shaped MnS nanocrystals with an average size of 17 nm (thickness) x 44 nm (length) were synthesized from the reaction of 4 mmol of MnCl(2) and 2 mmol of sulfur at 280 degrees C for 2 h. Shorter bullet-shaped MnS nanocrystals were synthesized from a 3:1 molar ratio of MnCl(2) and sulfur. Hexagon-shaped MnS nanocrystals were also obtained. All of the synthesized nanocrystals were highly crystalline.     

Analysis of human tear proteins by two-dimensional electrophoresis.

Human tear proteins in the conjunctival sac were separated on the basis of the differences in their isoelectric points and molecular weights using micro two-dimensional electrophoresis combined with immunoblotting. The two-dimensional electrophoretic patterns of tear proteins from patients with conjunctivitis were compared with those from normal individuals. We also measured integrated intensities of seven protein spots, lactoferrin (LF), albumin and five specific tear proteins (STP), to examine differences in the amounts of these proteins in tears from normal individuals of different sexes. In the tears from patients with conjunctivitis, secretory immunoglobulin A (IgA), LF and STP spots were stained more weakly, whereas the albumin spot was stained more strongly as compared with those from normal individuals. Furthermore, haptoglobin and IgG spots appeared in the tears from patients with conjunctivitis. These were more prominent in the tears from patients with severe conjunctivitis. There were significant differences in the amounts of LF and two kinds of STPs in the different sexes. The amounts of these proteins were larger in females.     

The removal and kinetic study of Mn,Fe, Ni and Cu ions from wastewater onto activated carbon from coconut shells

Activated carbon from coconut shells (ACCS) was synthesised and used for the removal of metal ions (manganese, iron, nickel and copper) from aqueous solutions. Two different adsorption models were used for analysing the data. Adsorption capacities were determined: copper ions exhibited the greatest adsorption on activated carbon obtained from coconut shells because of their size and pH conditions. Adsorption capacity varied as a function of the pH. Adsorption isotherms from aqueous solutions of heavy metals on ACCS were determined and were found to be consistent with Langmuir’s adsorption model. Adsorbent quantity and immersion enthalpy were studied. The results were compared with other adsorbents used in a prior study.     

Chemistry and biological activity of essential oils from Piper claussenianum (Piperaceae)

Analyses of essential oils obtained from fresh and dried leaves and inflorescences of Piper clausenianum were performed using GC-FID, GC-MS and NMR techniques. Forty compounds were detected for these four oils with the total of identified constituents ranging from 88.7% for the dried inflorescences to 97.7% for the dried leaves. Sesquiterpenes were the main constituents in the volatile fraction from leaves with a high percentage of (E)-nerolidol (up to 83%). However, monoterpenes were identified in greater amount in the inflorescences, with linalool percentages from 50% up. The essential oils from fresh leaves and inflorescences were submitted to anti-parasitic activity against a strain of Leishmania amazonensis. Both samples showed biological activity, but the essential oil from P. claussenianum fresh leaves, which was rich in (E)-nerolidol, showed effective growth inhibition of L. amazonensis due to the high percentage of this metabolite in the mixture.     

Hydrocarbons and aromatic hydrocarbons in groundwater surrounding an earthen waste disposal pit for produced water in the Duncan oil field of New Mexico

Samples of groundwater and soil were collected from test pits placed 25 m intervals on five axes extending from an earthen waste disposal pit for produced water near the San Juan River of northwest New Mexico. Samples were obtained at depths of 1.2 to 1.5 m and were analyzed using GC and GC/MS techniques for purgable hydrocarbons, including benzenes, and for solvent extractable organic compounds. Water samples from test pits down-gradient from the disposal pit contained purgable and extractable hydrocarbons that were similar to contents of the waste disposal pit. In contrast, water samples obtained from test pits up-gradient from the waste pit were free of detectable organic components. Major purgable components in the waste pit and in surrounding groundwater included saturated/unsaturated hydrocarbons and aromatic/alkylated aromatic hydrocarbons. Samples collected 25 m from the waste pit contained concentrations of all compounds greater than in samples taken at 50 m in distance on the same exis. Total concentration of purgable aromatic hydrocarbons in groundwater from test plots ranged from a high of 200 ppb at 25 m, to a low of 12 ppb at 50 m on an axis through the plume center.     

Evidence for thermal decomposition contributions to the mass spectra of chlorinated phenoxyacid herbicides obtained by particle beam liquid chromatography mass spectrometry

The spectral quality of a group of chlorinated phenoxyacid herbicides has been shown to degrade under certain conditions upon introduction into the mass spectrometer by a particle beam interface. Experiments were performed to investigate these changes in spectra. Normalized ion chromatograms were generated for the herbicides, and the results showed a broadening of the profiles of some ions, indicating a longer residence time in the ion source. These ions were postulated as coming from the ionization of thermal degradation products from the herbicides. The generation of these ions was dependent on ion source temperature, analyte concentration, and, by implication, ion source cleanliness. Tandem mass spectrometry experiments were performed on these ions from the herbicides and ions from the corresonding phenols. The tandem mass spectra of the ions from the herbicides were similar to the tandem mass spectra of the ions from the phenols. Therefore, it appears that the particle beam mass spectra of the chlorinated phenoxyacid herbicides are composite spectra with contributions from the gas phase ionization of the parent herbidides and thermal decomposition products.     

Determination of flumequine in channel catfish by liquid chromatography with fluorescence detection.

Rapid methods are described for determination of flumequine (FLU) residues in muscle and plasma of farm-raised channel catfish (Ictalurus punctatus). FLU residues were extracted from tissues with an acidified methanol solution, and extracts were cleaned up on C18 solid-phase extraction cartridges. FLU concentrations were determined by liquid chromatography (LC) using a C18 analytical column and fluorescence detection (excitation, 325 nm; emission, 360 nm). Mean recoveries of FLU from fortified muscle were 87-94% at 5 levels ranging from 10 to 160 ppb (5 replicates per level). FLU recoveries from fortified plasma were 92-97% at 5 levels ranging from 20 to 320 ppb. Limits of detection (signal-to-noise ratio, 3:1) for the method as described were 3 and 6 ppb for muscle and plasma, respectively. Relative standard deviations (RSDs) for recoveries were < or = 12%. Live catfish were dosed with 14C-labeled or unlabeled FLU to generate incurred residues. Recoveries of 14C residues throughout extraction and cleanup were 90 and 94% for muscle and plasma, respectively. RSDs for incurred FLU at 2 levels in muscle and plasma ranged from 2 to 6%. The identity of FLU in incurred tissues was confirmed by LC/mass spectrometry.     

Determination of ochratoxin A in wine and beer by immunoaffinity column cleanup and liquid chromatographic analysis with fluorometric detection: collaborative study.

The accuracy, repeatability, and reproducibility characteristics of a liquid chromatographic method for the determination of ochratoxin A (OTA) in white wine, red wine, and beer were established in a collaborative study involving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, and naturally contaminated materials at levels ranging from < or =0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted with a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liquid chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ranging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging from 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative standard deviations for between-laboratories reproducibility (RSDR) ranged from 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were < or =0.4 for the 3 matrixes.     

氢化诺卜醇及其烷基醚的合成与表征

由β-蒎烯与多聚甲醛反应制得诺卜醇,然后用Ni(R)催化氢化制得氢化诺卜醇(ROH),再将氢化诺卜醇与亚硫酰氯反应制得氢化诺卜基氯(RCl),由RCl分别与6种醇钠反应合成了6种氢化诺卜基烷基醚,各产物的得率均在92%以上,GC纯度95%以上。各产物都用IR,1H NMR,13C NMR与MS进行了结构表征。     

Serum protein profiles of patients with pancreatic cancer and chronic pancreatitis: searching for a diagnostic protein pattern.

In this study, 13 sera from patients with pancreatic cancer, 9 from chronic pancreatitis and 10 from healthy subjects were analyzed by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The MALDI mass spectra revealed the presence of several low molecular weight peptides, among which some were detected only in the sera from both pathological conditions. On the other hand many peptides were observed only in control sera, and were absent in the sera from the two diseases. Therefore, MALDI analysis of the low molecular weight fraction (<10 000 Da) of sera from patients with pancreatic diseases enabled us to identify the presence of some disease-related signals and also some signals characteristic of normal subjects.     

The emission characteristics of hydrocarbon from Chinese cooking under smoke control

To understand the hydrocarbon emissions in China, the source profile and emission factors of hydrocarbon species from cooking sources were measured. The measured commercial restaurants represented Sichuan cuisine, Zhejiang cuisine, household-style cuisine and Korean-style barbecue, respectively. Forty-one hydrocarbon species were quantified, in which the abundant species were n-butane, iso-butane, 2-methlybutane, pentane, propene, 1-butene, toluene and benzene. The hydrocarbon mixing ratios from Korean barbecue were evidently higher than those from the other Chinese-style restaurants, and the Sichuan-style restaurants had significantly higher emissions of iso-butane and d-limonene. The hydrocarbon source profiles of Chinese cooking were different from the profiles obtained from cooking sources of other cities. While the Korean-style barbecue had abundant species such as light alkanes, propene, benzene and toluene, similar to results for Western barbecue source, the relative percentages of these species were different, probably due to the difference in fuels for cooking. The hydrocarbon emission factors were estimated for Sichuan-style cuisine, which was 0.21g hydrocarbon per kg of meat cooked, much lower than that from the barbecue source.     

High-performance liquid chromatography and capillary supercritical-fluid chromatography separation of vegetable carotenoids and carotenoid isomers

Carotenoids from carrots and tomatoes were separated with high-performance liquid chromatography (HPLC) and capillary supercritical fluid chromatography (SFC). All trans alpha- and beta-carotene were separated from their respective cis-isomers with capillary SFC. Carotenoids extracted from tomatoes included xanthophyll, lycopene and beta-carotene, while alpha- and beta-carotene were extracted from carrots. The HPLC separations were accomplished isocratically with a 25-cm column containing 5-microns ODS and methanol-acetonitrile-chloroform (47:47:6) or acetonitrile-dichloromethane (80:20). beta-Carotene cis-isomers were separated with SFC with a SB-cyanopropyl-25-polymethylsiloxane column, while alpha-carotene isomers were separated with two SB-cyanopropyl-50-polymethylsiloxane columns. Carotenoids from carrots and tomatoes were separated with a SB-phenyl-50-polymethylsiloxane column. Carbon dioxide with 1% ethanol was the SFC mobile phase. The eluent was monitored at 461 nm for HPLC and either 453 or 461 nm for SFC.