4 research outputs found
Dipolar Direct Current Driven Collision-Induced Dissociation in a Digital Ceramic-Based Rectilinear Ion Trap Mass Spectrometer
A digital ion trap (DIT) and rectilinear ion trap (RIT)
have been
proven to be very useful technology in the past years. In this work,
the digital ion trap technology was combined with the ceramic-based
rectilinear ion trap (cRIT) system. The rectangular waveform was used
for ion trapping. A dipolar excitation waveform which was formed by
dividing down the trapping rectangular waveform was used for the ion
ejection. We found that the high efficient collision-induced dissociation
(CID) procedure could be obtained by simply manipulating the duty
cycle of the dipole excitation waveform, and it could significantly
simplify the tandem mass spectrometry analysis method and procedure
with an ion trap, since the dipolar direct current (dc) voltage could
be easily produced and applied to one of the pair of electrodes, which
was fully controlled by the computer software and does not need any
hardware modification
Efficient Enrichment of Global Phosphopeptides Using Magnetic Tannic Acid – Titanium(IV)/Zirconium(IV) Functionalized Spheres as a Novel Sorbent for Immobilized Metal Ion Affinity Chromatography (IMAC)
Inspired by the enrichment preferences of metal ions for phosphopeptides, a layered assembly method was adopted to introduce hydrophilic polyhydroxy ligands tannic acid (TA) to prepare magnetic bimetal ion-functionalized nanomaterials denoted by Fe3O4@TA@Ti4+/Zr4+ to provide the comprehensive enrichment of phosphopeptides. Benefiting from the excellent ion immobilization ability and unbiasedness for phosphopeptide enrichment, Fe3O4@TA@Ti4+/Zr4+ shows excellent properties for the enrichment and identification of global phosphopeptides. The results show that the material possesses high efficiency, outstanding selectivity (the maximum molar ratio β-casein to bovine serum albumin is 1:1000), a low detection limit of 0.4 fmol/μL, and the ability to be recycled at least 10 times. In addition, excellent performance was also demonstrated in the analysis of skimmed milk and human saliva: 13 and 31 phosphopeptides were successfully captured. The results demonstrate that the material has high potential for practical application in phosphoproteomics.</p
Genetic Algorithm Optimized Printed Circuit Board Ion Funnel Tandem Subambient Pressure Ionization with Nanoelectrospray (SPIN) for High Sensitivity Mass Spectrometry
The SPIN tandem ion
funnel (IF) structure allows for highly sensitive
mass spectrometry due to reduced ion losses in the interface region
and during transmission; however, IF has an inherent mass discrimination
problem, which can greatly restrain the ion transmission efficiency
(TE) and therefore requires certain optimization methods. Conventional
optimization methods ignore the combined effects of multiple IF characteristic
parameters (electrical and dimensional parameters) and are unable
to achieve efficient ion transmission over a wide mass range, thus
requiring significant tuning time. In this paper, a genetic algorithm
(GA)-optimized printed circuit board ion funnel (PCBIF) was designed,
fabricated, preliminarily evaluated, and integrated into the SPIN
interface to address the ion loss that can occur when mass spectrometers
transfer ions at subambient pressure. Simulation studies have showed
clearly that the effective automated GA can increase the PCBIF optimization,
design, and the ion TE (finding the optimal characteristic parameters
within 4 h and achieving 96% ion TE for ions with m/z between 50 and 700). Preliminary tests on built
SPIN-PCBIF-MS can lead to an LOD of 0.01 nM and also indirectly suggest
the effectiveness of the GA-optimized PCBIF. The proposed GA method
helps to guide the design of IF and can also be used for other multivariate
mass analyzers or ion transmission devices
Printed Circuit Board Ion Trap Mass Analyzer: Its Structure and Performance
An ion trap (IT) mass analyzer can
be simply built with low cost
materialî—¸the printed circuit board (PCB). A printed circuit
board ion trap (PCBIT) can perform ion trapping, mass analysis, and
tandem mass spectrometry as a conventional ion trap mass analyzer.
In a PCBIT, each PCB electrode was fabricated to specially designed
patterns with several separate electric strips. The strips’
electrodes were insulated from each other and applied with different
voltages during the experiment. Therefore, the electric field distribution
inside the ion trap region may be adjusted and optimized by simply
adjusting the voltage on each strip. The performance of the PCBIT
can also be optimized since the property of an ion trap is strongly
dependent on the field distribution. The fabrication, operation, and
performance of the PCBIT are described and characterized in this paper.
A prototype PCBIT was built with two pairs of 64 mm × 12 mm PCB
rectangular plates and one pair of 10 mm × 10 mm stainless steel
square plates. A mass analysis with a resolving power of over 1500
and a mass range of around 3000 Th was observed. The mass-selected
isolation and collision-induced dissociation (CID) of ions were also
tested using the homemade PCBIT system. The adjustable electric field
distribution, simple structure, and low cost of PCBIT make it certainly
suitable for the further miniaturization of the portable mass spectrometer