The analysis of volatile trace compounds in landfill gases,compost heaps and forest air

Landfill gas, cryotrapped on a loop fashioned from a length of a capillary gas chromatography (GC) column, was examined for volatile organometallic compounds (VOMCs) and for volatile organic compounds (VOCs) by using GC–mass spectrometry (MS). A large number of organic components were present and many were identified, but the only VOMCs present in high enough concentrations to be detected were trimethylstibine and tetramethyltin. The use of inductively coupled plasma (ICP)‐MS as an element‐specific detector allowed the identification of a number of other organometallic species in the landfill gas, including trimethylarsine and trimethylbismuth, and, for the first time, butyltrimethyltin and dibutyldimethyltin. The presence of molybdenum hexacarbonyl was confirmed. Gas from a large‐scale compost heap and from compost incubated in the laboratory contained iodomethane but no common VOMCs (GC–ICP‐MS). Only VOCs were present in forest air (GC–MS). Copyright © 2003 John Wiley & Sons, Ltd.     

Two new asterosaponins from the starfish Asterias rubens: application of a cryogenic NMR probe head

We report two new asterosaponins from the Baltic starfish Asterias rubens along with their ¹H and ¹³C NMR data. The compounds were isolated after on‐flow liquid chromatography–NMR–mass spectrometry screening indicated that they had not been identified before. The one‐ and two‐dimensional NMR experiments used to elucidate the structures were recorded using a 5 mm cryogenic probe head. The advantages of cryogenic probes for this kind of examination in comparison with conventional probe heads are discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

Applications of fast atom bombardment mass spectrometry (FAB MS) to organometallic and coordination chemistry

This article describes the technique of fast atom bombardment mass spectrometry (FAB MS) and its applications to the analysis of organometallic and coordination complexes. Sections on ion generation and matrices are followed by a Periodic Group-based review of FAB MS results obtained from Transition Metal and Main Group compounds, organometallic cluster carbonyls and their derivatives, and salts of poly-oxo-anions. The literature has been surveyed from 1981 to approximately mid-1986.     

Unexpected end‐groups of poly(acrylic acid) prepared by RAFT polymerization

Low‐molecular‐weight poly(acrylic acid) (PAA) was synthesized by reversible addition fragmentation chain transfer polymerization with a trithiocarbonate as chain‐transfer agent (CTA). With a combination of NMR spectroscopy and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, the PAA end‐groups of the polymer were analyzed before and after neutralization by sodium hydroxide. The polymer prior to neutralization is made up of the expected trithiocarbonate chain‐ends and of the H‐terminated chains issued from a reaction of transfer to solvent. After neutralization, the trithiocarbonates are transformed into thiols, disulfides, thiolactones, and additional H‐terminated chains. By quantifying the different end‐groups, it was possible to demonstrate that fragmentation is the rate limiting step in the transfer reaction. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5439–5462, 2004     

Ion chromatography–inductively coupled plasma mass spectrometry determination of arsenic species in marine samples

Arsenic speciation analysis in marine samples was performed using ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP‐MS) detection. The separation of eight arsenic species, viz. arsenite, monomethyl arsonic acid, dimethylarsinic acid, arsenate, arsenobetaine, tetramethylarsine oxide, arsenocholine and tetramethylarsonium ion was achieved on a Dionex AS4A (weaker anion exchange column) by using a nitric acid pH gradient eluent (pH 3.3 to 1.3). The entire separation was accomplished in 12 min. The detection limits for the eight arsenic species by IC–ICP‐MS were in the range 0.03–1.6 µ g l^?1, based on 3σ of the blank response (n = 6). The repeatability and day‐to‐day reproducibility were calculated to be less than 10% (residual standard deviation) for all eight species. The method was validated by analyzing a certified reference material (DORM‐2, dogfish muscle) and then successfully applied to several marine samples, e.g. oyster, fish muscle, shrimp and marine algae. The low power microwave digestion was employed for the extraction of arsenic from seafood products. Copyright © 2004 John Wiley & Sons, Ltd.     

Determination of Aroma Compounds in Blackberry by GC/MS Analysis

The aromatic composition of five blackberry cultivars (Bursa 2, Navaho, Nessy, Chester Thornless, and Jumbo) was studied. The Im-SPME (Immersion Solid Phase Micro Extraction) extraction technique was applied and the samples were analyzed by GC/MS. Furfural and its derivatives were found to be the major aromatic compounds and 5-hydroxymethylfurfural was the most abundant compound in all the blackberry varieties.     

气相色谱质谱法快速测定人血浆中克仑特罗

血浆样品经0.01mol·L-1盐酸和无水乙醇浸取,在碱性条件下用氯仿萃取,GG-MS-选择离子测量法测定,外标法定量。在选定的色谱条件下,盐酸克仑特罗的检出限为0.05ng,线性范围为0.1-100ng,方法的平均回收率为95.6％,RSD小于6.82％(n=6)。该法毋需衍生化,基质无干扰,简便可靠,适用于生物材料中克仑特罗的快速分析。     

Analysis of Chloramphenicol Residues in Honey by Liquid Chromatography–Tandem Mass Spectrometry

Antibiotics are often used in bee-keeping to control European and American foulbrood. The broad spectrum antibiotic chloramphenicol (CAP) was used for curative purposes in veterinary medicine, but is now forbidden in numerous countries, although still used in south-east Asia. A liquid-chromatographic method with tandem mass spectrometric detection (LC–MS–MS) has been developed for analysis of sub-g kg^–1 residues of chloramphenicol in honey. Results from full validation of the procedure and analysis of 75 honey samples obtained commercially in Switzerland are presented. These show the method is satisfactory and useful for monitoring chloramphenicol residues in honey.     

LC-ESI-MS/MS and cytotoxic activity of three Pistacia species

LC-ESI-MS/MS was used for a comprehensive characterisation of ethanol extract from the leaves of three Pistacia species. After optimisation of the method and the use of the negative ionisation mode, a total of 42 different compounds were identified, of which 22 were tentatively characterised in P. chinensis Bunge, 33 in P. khinjuk stocks and 25 in P. lentiscus L. leaves. Flavonoids, phenolic acids, and their derivatives were the most abundant identified compounds. LC-ESI-MS/MS revealed identification of 15, 18 and 6 not previously detected compounds in P. chinensis Bunge, P. khinjuk Stocks and P. lentiscus L., respectively. The three extracts were also tested for their cytotoxic activities against human PC3 prostate cancer, A549 lung cancer, MCF7 breast cancer and HepG2 liver cancer. Generally, all the extracts have a moderate cytotoxic activity against lung, breast and prostate cancer, with different IC₅₀. However, only P. lentiscus L. showed moderate activity against liver cancer.     

Synthesis and characterization of new polyamides derived from di(4-cyanophenyl)isosorbide

New optically active polyamides were synthesized according to two ways: using a microwave-assisted polycondensation of an optically active isosorbide-derived diacylchloride with different aromatic diamines in NMP and using interfacial polymerization from an isosorbide-derived diamine with different diacylchlorides. The polymers are obtained with inherent viscosities in the range from 0.11 to 1.05 dL/g. The DSC and TGA measurements clearly demonstrate the high thermal stability of these polymers when considering the range of the melting points from 200 °C to 300 °C and the absence of decomposition till 350 °C.