Quadrupole ToFMS

In recent years several new instruments have been developed based on different mass-spectrometer principles. Two different categories of ICP-MS instruments are currently commercially available low-resolution instruments (using either QMS, ITMS or ToF-MS) and focusing high-resolution instruments (DFS, FTMS). Selected specifications for these two categories are shown in Table 8.63. Both the quadrupole-based and the double-focusing instruments allow a sequential multielement measurement, whereas ICP-ToFMS allows... 

Quadrupole/TOF A version of the triple quadrupole is to replace the third quadrupole with a TOFMS. This provides potentially faster analysis and higher mass resolution. 

TOFMS analyzes all ions at once vs. quadrupole mass spectrometry, which can detect only one ion mass at a time. 

Figure 1.14 Transient signals for Cu and Cli produced by an electrothermal vaporization device and detected with (a) a quadrupole-based ICP-MS instrument and (b) a ICP-TOFMS instrument, when five isotopes were measured simultaneously.

MALDI-Fourier transform ion cyclotron resonance mass spectrometry MALDI-Q-ion mobility-TOFMS MALDI-Quadrupole-ion-trap-TOF mass spectrometry MALDI-TOF-imaging mass spectrometry MALDI Time-of-flight mass spectrometry Magnetic resonance imaging Matrix solution fixation Moxifloxacin... 

In order to identify the oxygen-carrying species responsible for the enhanced performance, it was decided to sample the converter gas phase by mass spectrometry. Since cesium can form suboxides with amu around 1,500 (CsjjOj) and because quadrupole mass spectrometers suffer from a transmission loss as the amu rises, a time-of flight mass spectrometer (TOFMS) was chosen. 

To prevent Cs ions fi-om reaching the TOFMS a quadrupole lens acts as a high-pass filter To that effect the low mass setting is at 140 amu and there is no mass sweep. 

MTs = metallothioneins NMR = nuclear magnetic resonance pKa = negative logarithm of acid dissociation constant PMT = photomultiplier tube QITMS = quadrupole ion trap mass spectrometry SBSE = stir bar sorptive extraction SDS-PAGE = sodium dodecylsulfate polyacrylamide gel electrophoresis Se-Cis = selenocystine Se-Cys = selenocysteine Se-Et = selenoethionine Se-Hcy = seleno-homocysteine Se-Met = selenomethionine SEC = supercritical fluid chromatography TBT = tributyltin TETRA = tetramethylarsonium ion Tf = transferrin TMAsO = trimethylarsineoxide TMSe = trimethylselonium ion TOFMS = time of flight mass spectrometry USN = ultrasonic nebulizer. 

Detection methods HPLC-DAD, HPLC with diode-array detection. HPLC-(ESI-MS), HPLC with electrospray ionization mass spectrometry. RP-HPLC, revcrsed-phase HPLC. UPLC/Q-TOFMS, UPLC with quadrupole-time of flight mass spectrometry. HPLC-APCI-MS, HPLC with atmospheric pressure chemical ionization mass spectrometry. CE-IT-MS, capillary elecliophoresis-ion-1r mass spectrometry. LC-ESI-ITMS, liquid chromatography-electrospray ionization ion trap mass spectrometry. LC-ELSD, LC with evaporative light scattering detector. DNBZ-Cl, 3,5-dinitrobenzoyl chloride. 

Expression CMS single quadrupole (Advion) with an ESI source Unique HT TOFMS (LECO) with an ESI source... 

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