@article {4787,
title = {Peak structure with a quadrupole mass filter operated in the third stability region},
journal = {International Journal of Mass Spectrometry},
volume = {197},
year = {2000},
note = {ISI Document Delivery No.: 291DFTimes Cited: 6Cited Reference Count: 11Sp. Iss. SI},
month = {Feb},
pages = {113-121},
type = {Article},
abstract = {Peak structure for a quadrupole operated in the third stability region with Mathieu parameters (a, q) approximate to (3, 3) has been studied experimentally and modeled theoretically. It is shown that the structure is due to the imaging properties of the quadrupole field which are caused by the wavelike properties of the ion trajectories. Ions enter the quadrupole through a small inlet aperture on axis. When ions are focused on the center of the exit aperture the transmission is a maximum. Conversely when ions have trajectories that place them near the rods at the exit aperture the transmission is a minimum and a dip appears on a peak. The positions of dips on a peak can be assigned to lines in the stability diagram. These lines follow iso-beta lines, where beta is the parameter that determines the frequencies of ion motion. The positions of the lines are controlled by the number of rf cycles, which ions spend in the quadrupole field. At high resolution (>300) and low ion axial energy (<20 eV) the peak splitting is minimal or absent. (C) 2000 Elsevier Science B.V.},
keywords = {FREQUENCIES, ION-TRAP, peak, peak shape, quadrupole mass filter, STRUCTURE, third stability region},
isbn = {1387-3806},
url = {://000085718300007},
author = {Du, Z. H. and Douglas, D. J. and Glebova, T. and Konenkov, N. V.}
}
@article {4101,
title = {Variance contributed by pressure induced injection in capillary electrophoresis},
journal = {Journal of Chromatography A},
volume = {767},
number = {1-2},
year = {1997},
note = {ISI Document Delivery No.: WY814Times Cited: 14Cited Reference Count: 12},
month = {Apr},
pages = {205-216},
type = {Article},
abstract = {The contribution of variance from a pressure injection to the final analyte peak in capillary electrophoresis (CE) is studied quantitatively. The band broadening process of CE can be described by the product of the Laplace transformed contributing factors; the inverse transform of the product gives the final peak shape which is the convolution of the original functions. The CE process is, therefore, similar to the chromatographic processes described by Sternberg. Based on the additivity of the variance, the injection induced variance is transferred directly to the final peak. The differences between the concepts of band broadening and peak broadening are discussed. Because the injection length from a pressure induced injection is the same for all analytes, and the migration rates during the CE separation are different for these analytes, the variance contributed by injection is larger for slower migrating analytes. The pressure forced flow generates a parabolic component in an injected sample plug, and this should also be considered in calculating the total injection length (tau). The variance is (1/16)tau(2) for a sample plug with a Gaussian concentration profile, and (1/12)tau(2) for one with a rectangular profile. It is demonstrated that the total variance of an analyte peak increases at the same rate as the injection variance. The difference between the total variance and the injection variance is contributed by longitudinal diffusion and other factors.},
keywords = {band broadening, injection methods, NUCLEOSIDES, nucleotides, peak broadening, peak shape, ZONE ELECTROPHORESIS},
isbn = {0021-9673},
url = {://A1997WY81400023},
author = {Peng, X. J. and Chen, D. D. Y.}
}