Quadrupole generation

Now, the quadrupole moment can next be calculated by differentiating the potential to get the electric field due to the dipole moment. The reader can now see that an infinite series can be thus generated. The total electric field is simply the sum of all the individual multipole contributions, given by... 

Figure 9.1 Generation of dipole and quadrupole moments by charges...

Tandem mass spectrometry (MS/MS) is a method for obtaining sequence and structural information by measurement of the mass-to-charge ratios of ionized molecules before and after dissociation reactions within a mass spectrometer which consists essentially of two mass spectrometers in tandem. In the first step, precursor ions are selected for further fragmentation by energy impact and interaction with a collision gas. The generated product ions can be analyzed by a second scan step. MS/MS measurements of peptides can be performed using electrospray or matrix-assisted laser desorption/ionization in combination with triple quadruple, ion trap, quadrupole-TOF (time-of-flight), TOF-TOF or ion cyclotron resonance MS. Tandem... 

Figure 5.41 The total-ion-current (TIC) trace and reconstructed ion chromatograms from the predicted pseudomolecular ions of Indinavir m/z 614) and its mono- (m/z 630) and dihydroxy metabolites (m/z 646), generated from full-scan LC-MS analysis of an incubation of Indinavir with rat liver S9. Reprinted by permission of Elsevier Science from Identification of in vitro metabolites of Indinavir by Intelligent Automated LC-MS/MS (INTAMS) utilizing triple-quadrupole tandem mass spectrometry , by Yu, X., Cui, D. and Davis, M. R., Journal of the American Society for Mass Spectrometry, Vol. 10, pp. 175-183, Copyright 1999 by the American Society for Mass Spectrometry.

Notes HR = High Resolution HR-ICPMS, Q = Quadrupole Q-ICPMS, 1 = First generation MC-ICPMS, 2" = Second generation MC-ICPMS. 

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