各類質(zhì)譜的優(yōu)缺點

1、各類質(zhì)譜的優(yōu)缺點1.磁質(zhì)譜BenefitsClassical mass spectraVery high reproducibilityBest quantitative performance of all mass spectrometer analyzersHigh resolutionHigh sensitivityHigh dynamic rangeLinked scan MS/MS does not require another analyzerHigh-energy CID MS/MS spectra are very reproducibleLimitationsNot we

2、ll-suited for pulsed ionization methods (e.g. MALDI)Usually larger and higher cost than other mass analyzersLinked scan MS/MS gives either limited precursor selectivity with unit produ ct-ion resolution, or unit precursor selection with poor product-ion resolutionApplicationsAll organic MS analysis

3、methodsAccurate mass measurementsQuantitation Isotope ratio measurements2.四極桿質(zhì)譜BenefitsClassical mass spectraGood reproducibilityRelatively small and low-cost systemsLow-energy collision-induced dissociation (CID) MS/MS spectra in triple qu adrupole and hybrid mass spectrometers have efficient conve

4、rsion of precursor t o productLimitationsLimited resolutionPeak heights variable as a function of mass (mass discrimination). Peak heigh t vs. mass response must be tuned.Not well suited for pulsed ionization methodsLow-energy collision-induced dissociation (CID) MS/MS spectra in triple quad rupole

5、and hybrid mass spectrometers depend strongly on energy, collision gas, pressure, and other factors.ApplicationsMajority of benchtop GC/MS and LC/MS systemsTriple quadrupole MS/MS systemsSector / quadrupole hybrid MS/MS systemsQuadrupole/ion trap hybrid MS/MS systemsQuadrupole/FTICR hybrid MS/MS sys

6、tems3.飛行時間質(zhì)譜BenefitsFastest MS analyzerWell suited for pulsed ionization methods (method of choice for majority of MALDI ma ss spectrometer systems)High ion transmissionMS/MS information from post-source decayHighest practical mass range of all MS analyzersLimitationsRequires pulsed ionization metho

7、d or ion beam switching (duty cycle is a factor)Fast digitizers used in TOF can have limited dynamic rangeLimited precursor-ion selectivity for most MS/MS experimentsApplicationsAlmost all MALDI systemsVery fast GC/MS systems4.傅立葉變換離子回旋共振質(zhì)譜BenefitsThe highest recorded mass resolution of all mass spe

8、ctrometersPowerful capabilities for ion chemistry and MS/MS experimentsWell-suited for use with pulsed ionization methods such as MALDINon-destructive ion detection; ion remeasurementStable mass calibration in superconducting magnet FTICR systemsLimitationsLimited dynamic rangeStrict low-pressure re

9、quirements mandate an external source for most analytical applicati onsSubject to space charge effects and ion molecule reactionsArtifacts such as harmonics and sidebands are present in the mass spectraMany parameters (excitation, trapping, detection conditions) comprise the experiment seq uence tha

10、t defines the quality of the mass spectrumGenerally low-energy CID, spectrum depends on collision energy, collision gas, and othe r parametersApplicationsIon chemistryHigh-resolution MALDI and electrospray experiments for high-mass analytesLaser desorption for materials and surface characterization5

11、.離子阱質(zhì)譜BenefitsHigh sensitivityMulti-stage mass spectrometry (analogous to FTICR experiments)Compact mass analyzerLimitationsPoor quantitationVery poor dynamic range (can sometimes be compensated for by using automatic gain control)Subject to space charge effects and ion molecule reactionsCollision energy not well-defined in CID MS/MSMany parameters (excitation, trapping, detection co