Spectrometry low resolution

Gas chromatography Liquid chromatography Infrared spectrometry Low resolution mass spectrometry... 

Mass spectrometry Low resolution spectra were determined with an MS9 instrument (AEI Ltd, Urmston, Manchester, U.K.) at 70 eV. A probe was used, normally at 100°. Molecular ions were also examined under high resolution. For A178, high resolution data were obtained using the ARC/FRI Mass Spectrometry Service (Food Research Institute, Norwich, Norfolk, U.K.) and perfluoro-kerosine as reference. 

Electron-impact mass spectrometry Low-resolution mass spectrometry operated in the electron-impact ionization mode. 

Mass spectrometry. Low resolution mass spectra were recorded at 25 eV with a V. G. Micromass 12B mass spectrometer. This was interfaced via a glass jet separator to a Varian 2400 gas chromatograph fitted with a single 2 m x 2 mm glass column packed with 3% SE-30 on 100-120 mesh Gas Chrom Q (Applied Science Laboratories, State College Pa., U.S.A.). The column was temperature programmed from 170 to 280 at 2 /min with the injector block and transfer line temperatures maintained at 270 and 230 respectively. Helium at 30 ml/min was used as the carrier gas. 

Tate, J. U. and Petri Jaakkola. The Use of Portable Low-Resolution FI -IR for liiuustriai Gas Analysis. In Petri Jaakkola, Indicstrial Applications of Low Resolution FF-IR Gas Phase Spectrometry. Annates Universitatis Turkuensis, Set. A 1 Tom. 222, Astronomica—Cliemica—Phys-ica—Mathematica, University of Turku (1997],pp. 9.3-115. 

Commercial Instruments Because of the proliferation of applications of mass spectrometry in organic and analytical chemistry, there are instruments marketed by numerous companies today. Some of the popular ones are the low resolution, single focusing model 21-490 and the high resolution, double focusing models, 21-492 and 21-110 of Du Pont de Nemours Co, and the double focusing model MS-9 of Associated Electrical Industries... 

In this core, concentrations of PCBs (determined as Aroclor 1254 and 1260, by high resolution gas chromatography, electron capture detection and high resolution gas chromatography-low resolution mass spectrometry) were <30 ng and those of total DDT (p,p DDT + p,p DDD + p,p DDE) <5 ng g Campesan et al. (21) in 11 sediment samples from Valle di Brenta, determined by GC-ECD the following mean concentrations (ng gd.w.) ... 

P.C. Jurs, B.R. Kowalski and T.L. Isenhour, Computerized learning machines applied to chemical problems. Molecular formula determination from low resolution mass spectrometry. Anal. Chem., 41 (1969)21-27. 

HRLEELS plasma mass spectrometry High-resolution low-energy electron plasma-mass spectrometry (see TI-IDMS)... 

Huber, J.F.K., Kenndler, E., Reich, G. (1979). Quantification of the information content of multi-dimensional gas chromatography and low resolution mass spectrometry in the identification of doping drugs. J. Chromatogr. 172, 15-30. 

Dihazi, G.H., and Sinz, A. (2003) Mapping low-resolution three-dimensional protein structures using chemical cross-linking and Fourier transform ion-cyclotron resonance mass spectrometry. Rapid Comm. Mass Spectrom. 17, 2005-2014. 

Smith [83] classified large sets of hydrocarbon oil infrared spectral data by computer into correlation sets for individual classes of compounds. The correlation sets were then used to determine the class to which an unknown compound belongs from its mass spectral parameters. A correlation set is constructed by use of an ion-source summation, in which a low resolution mass spectrum is expressed as a set of numbers representing the contribution to the total ionisation of each of 14 ion series. The technique is particularly valuable in the examination of results from coupled gas chromatography-mass spectrometry of complex organic mixtures. 

Pyrolysis-Gas Chromatography-Mass Spectrometry. In the experiments, about 2 mg of sample was pyrolyzed at 900°C in flowing helium using a Chemical Data System (CDS) Platinum Coil Pyrolysis Probe controlled by a CDS Model 122 Pyroprobe in normal mode. Products were separated on a 12 meter fused capillary column with a cross-linked poly (dimethylsilicone) stationary phase. The GC column was temperature programmed from -50 to 300°C. Individual compounds were identified with a Hewlett Packard (HP) Model 5995C low resolution quadruple GC/MS System. Data acquisition and reduction were performed on the HP 100 E-series computer running revision E RTE-6/VM software. 

Bay, Massachusetts. Gas liquid chromatography was used to detect hydrocarbons present at different depths in the sediment, while low resolution mass spectrometry was employed to measure concentrations of paraffins, cycloparaffins, aromatics and polynuclear aromatics. Their data show that the concentrations of total and saturated hydrocarbons decreased with increased depth, and it was noted that identification and quantification of hydrocarbons in oil-contaminated sediments is required if the fate of these compounds in dredge spills is to be determined. 

Crawford, L. R., Morrison, J. D. Anal. Chem. 43, 1971, 1790-1795. Computer methods in analytical mass spectrometry. Development of programs for analysis of low resolution mass spectra. 

Finally, low resolution mass spectrometry (LRMS) is applied to each separation fraction which exceeds a specified concentration when referred to the sample sources. The present levels are 0.5 fig/rn for gas streams, 1 mg/kg for solids, and 0.1 mg/1 for liquids. The selection of this particular technique, firmly in the middle of a transition between Levels 1 and 2, caused many philosophical problems concerning its proper use. The original Level 1 scheme did not contain LRMS. It has been included in the modified strategy to prevent potential triggering of Level 2 efforts based on large amounts of suspicious, but innocuous, oiganics. However, LRMS can be costly if constraints are not placed on how frequently it is applied. 

Additional analysis of these samples using the liquid chromatographic separation, total chromatographable organics, infrared, and low resolution mass spectrometry demonstrated that the sampling and analysis scheme produced reproducible data as shown in Table IV. 

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