Development and Characterization of a Field-Deployable Ion-Trap Mass Spectrometer with an Atmospheric Pressure Interface

A field-deployable quadrupole ion-trap mass spectrometer with an atmospheric pressure interface is designed, built, and characterized. The instrument enclosure (48 cm × 43 cm × 42 cm) includes a roughing pump and a helium lecture bottle; the total weight of the instrument is 68 kg. Peak power consumption during the instrument operation is ∼500 W. The instrument has a mass range of <i>m</i>/<i>z</i> 30–2500, across which it provides better than unit mass resolution. The typical peak width at half height is 0.3 Th for a scan speed of 4000 Th/s. Operation of the instrument with electrospray and atmospheric-pressure matrix-assisted laser desorption ionization (AP-MALDI) ion sources is demonstrated. AP-MALDI analysis of low femtomole amounts of peptides reveals that the sensitivity of the instrument is on par with modern commercially available quadrupole ion-trap mass spectrometers. Tandem mass spectrometry capabilities of the instrument include simultaneous isolation and fragmentation of several different compounds. Two ways to reduce the size, weight, and power consumption of the portable instrument were explored, and results of these initial studies are presented. One of the ways includes utilization of hydrogen as a buffer gas for operation of the ion-trap mass analyzer in combination with a metal hydride method for storage of hydrogen in a compact rechargeable cartridge. Furthermore, careful selection of the inlet capillary dimensions allowed to eliminate the first “1 Torr” stage of the differential pumping without any significant loss of the instrument sensitivity. The elimination of this first pumping stage removed two turbo drag pumps, which substantially decreased the instrument’s maximum power consumption (to ∼300 W in peak use, and ∼150 W during standby), as well as its size (to 30 cm × 43 cm × 50 cm) and weight (to 35 kg)

MOESM3 of ApoE deficiency exacerbates the development and sustainment of a semi-chronic K/BxN serum transfer-induced arthritis model

Additional file 3. Alteration of levels of circulating cytokines/chemokines in C57BL/6 and ApoE−/− mice with induction of arthritis. Serum levels from non-arthritic and arthritic C57BL/6 (control, n = 2 non-arthritic and n = 13 arthritic) and ApoE−/− (n = 3 non-arthritic and n = 6 arthritic) mice at 4–6 months. Data are represented as mean ± SEM. * denotes statistically significant differences. *p < 0.05, **p < 0.01,***p < 0.001

Additional file 1: Table S1. of Conditional deletion of caspase-8 in macrophages alters macrophage activation in a RIPK-dependent manner

Affymetrix QuantiGene 2.0 custom panel 21522 for analysis of macrophage polarization. Figure S1. Genotype validation of splenocyte populations. Figure S2. Genotype validation of BMDMs. Figure S3. TLR9 in vivo activation induces upregulation of serum cytokines and chemokines at similar levels in Casp8 fl/fl and Cre LysM Casp8 fl/fl mice. Figure S4. Caspase-8–deficient splenic myeloid populations are not predisposed to aberrant death. Figure S5. Caspase-8–deficient BMDMs express Fas. Figure S6. Caspase-8–deficient BMDMs undergo caspase-independent cell death in response to apoptotic stimuli. Figure S7. Caspase-8 deficiency in macrophages alters the response to TLR activation in vitro. Figure S8. Caspase-8 deficiency in macrophages alters the genetic profile in response to macrophage polarization in vitro. (PDF 5409 kb

Additional file 2: Table S2. of Conditional deletion of caspase-8 in macrophages alters macrophage activation in a RIPK-dependent manner

ANOVA comparison data from Affymetrix QuantiGene 2.0 custom panel 21522 for analysis of macrophage polarization. (XLS 68 kb