High-resolution mass spectrometer HRMS

Sector High-Resolution Mass Spectrometer (HRMS)... 

SiUcon-carbon and silicon-nitrogen multiply bonded compounds a high-resolution mass spectrometer (HRMS). 

Decision 2002/657/EC introduces criteria for confirmatory analysis, based on the so called identification points (IPs). Then, for confirmation of Group A substances, a minimum of four IPs are required, whereas for compounds listed in Group B the minimum number of IPs is set to three for a satisfactory confirmation of a compounds identity. Although the cited document still accepts detection techniques like diode-array (DAD) and fluorimetric detection (ELD) as possible confirmatory techniques, the confirmation of veterinary residues in food is performed nowadays by LC coupled to different MS detection systems. The system of IPs relies on the identification power of the different mass analyzers. For instance, a low resolution mass spectrometer (e.g., triple quadru-pole, QqQ or ion trap IT), provides 1.0 IP for the precursor ion and 1.5 IPs for each product ion. By contrast, high resolution mass spectrometers (HRMS resolution >20,000 fwhm, full width at half maximum) provide 2.0 IPs for the precursor ion and 2.5 IPs for each product ion, which means that (2 + 2.5n) IPs can be acquired when working in the product ion scan mode. In addition to IPs, the retention time of the suspected peak has to correspond to the measured retention time of the relative standard, and the area ratio between the selected ion traces has to be equal in the sample and in the standard [12]. 

Extracts from the sediment cores were analysed in a GC/HRMS, gas chromatography/high resolution mass spectrometer. The result is demonstrated in the table in Figure 2. 

Low resolution mass spectra (LRMS) and high resolution mass spectra (HRMS) were recorded on an Associated Electronic Industries (AEI) Model MS-30 spectrometer. Intrinsic viscosities were measured by standard procedures using a Cannon-Ubbelohde semi-micro viscometer (dilution viscometer). Differential scanning calorimetry data for polymers were taken on a Perkin-Elmer DSC IB all data on thermal transitions are reported in degrees centigrade and are uncorrected. 

Organometallic samples for NMR spectroscopic measurements were prepared in the glove box by use of J. Young valve NMR tubes (Wilmad 528-JY). H and NMR spectra were recorded on a Bruker-400 spectrometer (FT, 400 MHz for H 100 MHz for or a JEOL-AL300 spectrometer (FT, 300 MHz for H 75 MHz for at room temperamre, unless otherwise noted. High-resolution mass spectra (HRMS) were recorded on a Bruker Apex IV FTMS mass spectrometer using ESI (electrospray ionization). Microelemental analyses were performed on an Elemental Analyzer Vario EL apparatus. 

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