Water analysis by spark-source mass-spectrometry after preconcentration on activated carbon

For trace analyses of environmental waters, spark-source mass-spectrometry has been combined with a preconcentration procedure involving chelation of the dissolved trace elements with oxine and subsequent adsorption of the oxinates and naturally occurring organic and colloidal metal species onto activated carbon. The activated carbon is filtered off and ashed at low temperature. The residue is dissolved, an internal standard and pure graphite are added and, after drying, the electrodes are prepared. The photographically recorded mass spectrum is evaluated by a suitable computer routine. The error of the procedure is around 30%. While this preconcentration and analysis procedure is capable of measuring about 40 elements quantitatively, in practice 10-25 trace elements are determined simultaneously above the 0.1-mug/l. detection limit, as is illustrated by analyses of drinking water, surface and ground water samples. Although a sophisticated technique, SSMS can be considered for regular panoramic survey analyses.     

InclusiveK *+(890),K *+(1430) and\bar K^{ * - } (890) production inK + p interactions at 32 GeV/c

We present final results on inclusive production ofK ^*+(890),K ^*+(1430) andK ^*?(890) in \(\bar K^ + p\) interactions at 32 GeV/c, based on a statistics of ～27 events/μb. Total cross sections,p _T -andx-dependence of inclusive distributions are compared with experiments at other energies and with the Lund fragmentation model. Spin density matrix elements of theK ^*+(890) are also discussed. The results suggest that “recombination” of both initial state valence quarks \(\bar s\) andu of theK ⁺ intoK ^*+(890), responsible in the Lund model for ～45% of theK ^*+(890) cross section, is strongly suppressed.     

Neutral strange particle production inK + p interactions at 32 GeV/c

The production properties ofK _s ⁰ , \(\bar \Lambda\) andK ⁺ p interactions at 32 GeV/c are investigated using the final statistics of the experiment. We present total and semi-inclusive cross sections and aver-age multiplicities. Estimates are given of the diffractive dissociation contributions to total and differential cross sections. Thex-,p _T ^?, and transverse mass dependence of inclusive and semi-inclusive distributions is discussed as well as properties of “prompt”K _s ⁰ 's. The ratio of “prompt”K ₈₉₀ ⁺ (K ₈₉₀ ⁰ ) to “prompt”K ⁰ cross sections is measured to be 1.03±0.12 (0.98±0.17). From a comparison of \(\bar \Lambda\) production inK ^± p interactions at 32 GeV/c, we estimate a strange sea-quark suppression of 0.26 ±0.02. The double differential cross sections ofK _s ⁰ 's is studied as a function of Feynman-x andp _T ² , and a Triple-Regge fit performed. The data are compared in detail to versions of the Lund-model for low-p _T hadronic collisions.     

Stable gaseous aziridinium ions

Gaseous protonated aziridine ions are produced at the threshold from β-phenoxyethylamine molecular ions. The evidence for this is collisional activation spectra, using various precursors (including labelled analogues) under electron impact and field ionization conditions. Partial conversion to the acyclic \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH = }\mathop {\rm N}\limits^ + {\rm H}_{\rm 2} $\end{document} isomer occurs at higher electron energies and is rationalized by means of a potential energy surface constructed from energetic data.     

Metabolic profiling of urinary organic acids by single and multicolumn capillary gas chromatography

High-resolution gas chromatography (HRGC) and gas chromatography/mass spectrometry (GC/MS) are the techniques of choice to determine the retention indices of more than 200 organic acids as their trimethylsilyl (TMS) or oxime-trimethylsilyl derivatives. Several types of apolar and semipolar fused-silica capillary columns (OV-1, SE-52, and OV-1701), used to analyze and separate organic acids isolated from urine samples, are evaluated.     

The chemical ionization mass spectra of 2-tert-butyl-substituted 1,3-cycloalkanediol diacetates and dimethyl ethers

The chemical ionization (CI) mass spectra of the 2-tert-butyl-substituted 1,3-cyclopentane- and 1,3-cyclohexanediol diacetates and dimethyl ethers have been determined using isobutane and methane as reagent gases. From the differences in the spectra of these compounds, it clearly follows that steric and conformational effects are expresssed in the CI mass spectra. The relative impact of these effects, however, is strongly dependent on diol derivatization and 2-alkyl substitution.     

Electron-impact-induced fragmentation of aromatic cyclic diazoketones

The mass spectra of eleven diazoketones have been obtained. High resolution mass measurements of selected ions have shown initial loss of nitrogen followed by loss of carbon monoxide. In many of the spectra, flat-topped metastables were observed.     

New sensitive liquid chromatography method coupled with tandem mass spectrometric detection for the clinical analysis of vinorelbine and its metabolites in blood, plasma, urine and faeces

A new sensitive and specific liquid chromatographic method coupled with tandem mass spectrometric detection was set up and validated for the simultaneous quantitation of vinorelbine, its main metabolite, 4-O-deacetylvinorelbine and two other minor metabolites, 20'-hydroxyvinorelbine and vinorelbine 6'-oxide. All these compounds, including vinblastine (used as internal standard) were deproteinised from blood, plasma and faeces (only diluted in urine), analysed on a cyano column and detected on a Micromass Quattro II system in the positive ion mode after ionisation, using an electrospray ion source. Under tandem mass spectrometry conditions, the specific product ions led one to accurately quantify vinorelbine and its metabolites in all biological fluids. In whole blood, linearity was assessed up to 200 ng/ml for vinorelbine and up to 50 ng/ml for the metabolites. The limit of quantitation was validated at 250 pg/ml for both vinorelbine and 4-O-deacetylvinorelbine. In the other biological media, the linearity was assessed within a same range and the limit of quantitation was adjusted according to the expected concentrations of each compound. This method was initially developed in order to identify the metabolite structures and to elucidate the metabolic pathway of vinorelbine. Thanks to its high sensitivity, this method has enabled the quantitation of vinorelbine and all its metabolites in whole blood over 168 h (i.e., 4-5 elimination half lives) whilst the previous liquid chromatographic methods allowed their measurement for a maximum of 48-72 h. Therefore, using this method has improved the reliability of the pharmacokinetic data analysis of vinorelbine.