mass-to-charge ratio


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mass-to-charge ratio

[¦mas tə ′chärj ‚rā·shō]
(analytical chemistry)
In analysis by mass spectroscopy, the measurement of the sample mass as a ratio to its ionic charge.
References in periodicals archive ?
Caption: FIGURE 3: Correlations between the intensities of each mass-to-charge ratio (m/z) and each urinary protein/urinary creatinine (UP/UCr) ratio.
This approach is highly selective and only molecular species with the desired combination of the precursor and product ion mass-to-charge ratio (m/z) are transmitted to the detector.
Ionized proteins are accelerated in an electrical field and their mass-to-charge ratio measured.
In a perfect dendrimer structure each -N[H.sub.2] group "carries" roughly 200 Da of mass and it is obvious that because of increased mass-to-charge ratio the cyclic product should have lower electrophoretic mobilities.
analyzer detection, ionization of protein molecules, and mass-to-charge ratio separation.
MS enables identification of the composition of a compound based on its mass-to-charge ratio. A sample is ionized, and the charged molecular particles are propelled through an electromagnetic or electric field for separation by differences in mass (molecular weight).
The concept of mass spectrometry consists of fragmenting molecules and creating ions in a gas phase under high vacuum, and then separating the fragments according to their mass-to-charge ratio. The technique requires a very small amount of sample, can elucidate structural information and determine molecular weight.
These peptides can be quantified by use of selected reaction monitoring, which specifically selects the mass-to-charge ratio (m/z) of an enzyme-generated peptide and then detects a specific fragment ion of the peptide generated within the mass spectrometer.
The discrimination of the mass filter is really performed on the basis of the mass-to-charge ratio. As a result, the amount of time spent analyzing a sample is directly related to the number of elements analyzed.
In MRM mode (1), the respective observed T2 [[M + 2H].sup.2+] ions, mass-to-charge ratio (m/z) [beta], 466.8, and [delta], 480.3, were selected and fragmented, and the most informative singly-charged peptide fragments VTALWGK, 675.4, and VNALWGK, 688.4, targeted.
The first three designs are scanning-type instruments that adjust electrical, magnetic, or radio-frequency fields to allow ions of a single mass-to-charge ratio to the detector at a given time.
(3) identified peaks at an initial mass-to-charge ratio (m/z) and matched peaks by considering peaks within [+ or -] 0.2% of molecular weight to be the same peak.