Vocus CI-TOF Measurement System
Chemical ionization mass spectrometers for measuring gas and particle species.
- Bipolar Operation: Allows for positive and negative ion detection
- Ultimate Flexibility: Interchangeable gas and particle inlets and ionization sources for selective detection of different chemical classes
- High Sensitivity: Sub pptv detection of a wide range of gas and particle analytes
- Real Time Measurements: >10 Hz of volatile organics and inorganic compounds (VOCs and VICs) instantaneously
- High Mass Resolving Power: Enables elemental composition measurements and separation of isobars
- Field Portable Assembly: Can be used in aircraft, mobile laboratories
VocuS Accessories
Multi Selector System and Soil Probes
A flexible, field-deployable gas probe array for monitoring biogeochemical changes in ecological and agricultural research.
Field Enclosure
Rugged, field-ready with a corrosion free design. Ideal for long-term deployments.
Interchangeable Reactors & switchable reagent ions
Fast Reagent Ion Switching
Reagent ion switching enables real-time monitoring using different reagent ions with a single reactor. Switching timescales are 50-100 ms for the Aim Reactor, as as fast as 10 s for the PTR Reactor.
VUV Reagent Ion Source
A bright, safe, and robust ion source for generation of a variety of reagent ions used in Vocus Aim.
Available reagent ions enable detection of a wide range of species.
Reference
Isaacman-VanWertz et al., Using advanced mass spectrometry techniques to fully characterize atmospheric organic carbon: current capabilities and remaining gaps. Faraday discussions. 2017; 200: 579-98.
| Reagent Ion | Analyte Compound Classes | Reactor |
|---|---|---|
|
H3O+ (PTR) |
Small oxygenated compounds, polar molecules, BTEX, PAHs, other aromatics |
PTR |
|
NH4+ |
Highly functionalized VOCs, oxygenated compounds, peroxides |
PTR / Aim |
|
NO+ |
Alcohols, substituted aromatics, cyclic and branched alkanes, long-chain semi-volatile alkanes |
PTR |
|
O2+ |
Alkanes, carbon disulfide, halogenated compounds |
PTR |
|
I– |
Oxygenated organics, acids, peroxides, inorganic acids, inorganic compounds, oxygenated peroxy Radicals (RO2) |
Aim |
|
Br– |
Iodine containing compounds, HO2 radicals, mono carboxylic acids, iodine radicals |
Aim |
|
Protonated Acetone Dimers |
Amines, Ammonia |
Aim |
|
NO3– |
Highly acidic gases (i.e. H2SO4), low volatility oxidized organic gases |
NO3 |
|
Na+ |
Secondary organic aerosol species |
EESI |
Multiple Gas & Particle Inlets
Gas Chromatograph
Our Fast Compact GC system can be attached to the front of the Vocus for thermal desorption preconcentration for insitu analysis of VOCs and OVOCs.
FIGAERO (Filter Inlet for Gas & Aerosols)
The FIGAERO is an aerosol sampling inlet/interface for analysis of organic aerosol chemical composition and volatility.
VIA (Vaporization Inlet for Aerosols)
The Vaporization Inlet for Aerosols (VIA) is used for thermal desorption of organic aerosols for on-line analysis by the Vocus.
Possible Inlet/Reactor Combinations
CI-TOF Models
| CI-TOF Models | Scout | S | 2R | B2 | B4 |
|---|---|---|---|---|---|
|
Sensitivity cps/ppb |
4,000 |
30k |
30k |
10k |
10k |
|
Resolving Power
Th/Th M/ΔM |
3,500 |
5,000 |
10,000 |
5,000 |
10,000 |
|
LOD (pptv, 1 minute) |
<10 |
<1 |
<1 |
< 1 |
< 1 |
|
Bipolar Analyzer Switch |
10 min |
10 min |
10 min |
50 ms |
50 ms |