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 material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