Posted in | Hydrogen Equipment

Chemical Ionization with Vocus CI-TOF

Vocus CI-TOF from TOFWERK enables immediate measurement of trace substances in the air.

Instantaneous Analysis

It is possible for users to directly sample air to measure, define, and report volatile organic and inorganic compounds (VOCs and VICs) in complicated mixtures in real-time, without chromatography.

Unmatched Performance

Vocus offers sub-ppt limits of detection for a different range of compound classes.

Built for Exploration

Laboratory performance that can be taken anywhere. A sturdy and sleek design means that the instrument goes where the sample is, not the other way around.


An extensive toolbox to fulfill the requirements of researchers and industry.

Image Credit: TOFWERK

Real-Time Measurements

Report concentrations of volatile inorganic and organic compounds (VICs and VOCs) instantly.

Interchangeable Reactors

Users can increase the range and diversity of detectable compounds by exchanging the PTR and Aim Reactors. Let the instruments grow with the research or measurement goals by the addition of multiple reactors during purchase, or upgrade later as research directions changes.

Magnification Interface

It is possible for the users to transfer ions from the Vocus reactor to the TOF analyzer with the greatest possible efficiency for enhanced sensitivity.

High Resolution Separation

Individual isobars allow for confident and robust analysis of complicated mixtures.

Fast Reagent Ion Switching

Reagent ion switching allows real-time monitoring utilizing various reagent ions with a single reactor. Switching timescales are between 50 and 100 ms for the Aim Reactor and as quick as 10 seconds for the PTR Reactor.

VUV Reagent Ion Source

A bright, secure, and strong ion source for the production of a range of reagent ions utilized in Vocus Aim.

Optimized for use in Laboratory, Industrial, and Mobile Applications

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Image Credit: TOFWERK


Reactors for Flexible Ionization

Users can target their compounds of interest. Vocus ionizes molecules by regulated reactions with reagent ions in a reactor.

Chemical Ionization with Vocus CI-TOF

Image Credit: TOFWERK

Users can make use of one reactor with a single reagent ion.

Or, use one reactor that has the potential to switch between several reagent ions in a single experiment.

Or, exchange two reactors with various reagent ions.


The PTR reactor (Proton Transfer Reaction) is an efficient system that has been developed for the analysis of a wide range of volatile organic compounds (VOCs). The proprietary Vocus PTR Reactor decreases wall losses and concentrates ions with radiofrequency (RF) fields to give users the utmost sensitivity and lowest detection limits.

Furthermore, the Vocus PTR Reactor is additionally compatible with other reagent ion schemes, such as ammonium adduct ionization —to target wider ranges of compounds.

Available PTR Reagent Chemistries

Table 1. Source: TOFWERK

Reagent Ion Analyte Compound Classes Example Applications
H3O+ (PTR) Small oxygenated compounds, polar molecules, BTEX, PAHs, other aromatics Air quality analysis, food and flavor, environmental contamination
NH4+ Highly functionalized VOCs, oxygenated compounds, peroxides Explosives and narcotics detection, photochemical oxidation products
NO+ Alcohols, substituted aromatics, cyclic and branched alkanes, long-chain semi-volatile alkanes Vehicle exhaust, wine contaminants
O2+ Alkanes, carbon disulfide, ammonia, halogenated compounds Ambient air monitoring, vehicle exhaust



The Vocus Aim reactor provides the quick and sensitive detection of trace organic and inorganic compounds covering the complete volatility range. The flow tube reactor functions at an increased pressure to repress fragmentation of analyte ions and makes use of small VUV sources to produce both positive and negative reagent ions.

Ultra-sensitive chemical ionization via the usage of flexible reagent ion chemistries enables sensitive and selective ionization of a range of compounds.

Available Aim Reagent Chemistries

Table 2. Source: TOFWERK

Reagent Ion Analyte Compound Classes Example Applications
I Oxygenated organics, acids, peroxides, inorganic acids, inorganic compounds Ambient air monitoring, biomass burning, SOA formation, semiconductor
Br Iodine containing compounds, HO2 radicals, mono carboxylic acids Ambient air monitoring, sea emissions


Detection Suitability

With a range of reactors and reagents, the Vocus CI-TOF offers users maximum flexibility while specific compound classes have been targeted.

Chemical Ionization with Vocus CI-TOF

Image Credit: TOFWERK


The Vocus Aim Reactor helps to remove fragmentation while volatile compounds are being targeted.

Chemical Ionization with Vocus CI-TOF

Image Credit: TOFWERK


Models and Specifications

Choose the Reagent Ions for Analysis

The Vocus CI-TOF comes with a range of reagent ions — every ion being optimized for particular classes of compounds.

Table 3. Source: TOFWERK

Application Common Reagent Ions
Ambient Air Monitoring PTR (H3O+), NH4+, O2+, NO+, I, Br
Food, Flavor, and Fragrances PTR (H3O+), NH4+, NO+, I
Breath Analysis PTR (H3O+), NH4+
Semiconductor AMC O2+, NH4+, I


Choose the Vocus CI-TOF Model

Table 4. Source: TOFWERK

  Resolving Powera LOD PTR LOD Aim Sensitivity PTR Sensitivity Aim Size Power
1 min | 1 s
1 min | 1 s
> cps/ppb
> cps/ppb
kg | mm W
2R 10000 1 | 10 1 | 10 30000 30000 170 | 480 x 615 x 1480 800
S 5000 1 | 10 1 | 10 30000 30000 130 | 480 x 615 x 1130 800
Scout 4000 5 10 4000 4000 130 | 480 x 615 x 1130 800
Eiger 2200 20 1000 95 | 422 x 630 x 840 600
Elf 500 20 500 55 | 380 x 500 x 650 450


a. Resolving power at specified sensitivity.  Each model can be operated with higher resolving power at reduced sensitivity.

Standard Components with Each Model

  • Standby Valve: enables servicing and interchange of Vocus reactor hardware in the absence of venting (Models 2R, S, and Scout)
  • Library of detectable compounds
  • Tofware data post-processing
  • Thuner software: Availability of automatic mass spectrometer tuning software
  • Shipping container: Deployment with no disassembly needed.
  • Touch screen control
  • Vocus acquisition and control software.
    • Automated gas calibration and zeroing with programmable cycling can be done
    • Real-time reporting of calibrated concentrations for target compounds
    • Single-click transitions between ready, shutdown, and sleep states

Other Equipment

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