TOFWERK’s Vocus CI-TOF facilitates instantaneous measurement of air’s trace materials.

Instantaneous analysis

Without the need for chromatography, users can sample air directly to characterize, measure, and detail volatile inorganic and organic compounds (VICs and VOCs) in compounded mixtures in actual time.

Unmatched performance

Vocus provides sub-ppt limits of identification for a distinct range of compounds.

Built for exploration

Lab performance that goes anywhere. A compact and rugged design means that your instrument goes where your sample is, not the other way around.


Availability of a comprehensive toolbox to fulfill the requirements of the industry and researchers.

Real-time measurements

Users can report concentrations of volatile inorganic and organic compounds (VICs and VOCs) instantly.

Interchangeable reactors

It is possible for users to 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 adding multiple reactors. This can be done during the purchase or upgraded later as the shift in research directions.

Magnification interface

Ions could be transferred from the Vocus reactor to the TOF analyzer with the maximum possible efficiency for enhanced sensitivity.

High resolution separation

Isobars can be segregated to allow the confident and robust analysis of complicated mixtures.

Fast reagent ion switching

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

VUV reagent ion source

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


Breath Analyzer

Non-invasive, ultra-sensitive breath analysis for disease diagnosis. Quickly detects single digit sub-ppt metabolites found in breath.

Image Credit: TOFWERK


Reactors for flexible ionization

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

Chemical Ionization with Vocus CI-TOF

Image Credit: TOFWERK

Make use of one reactor with a single reagent ion.

Or, it is enough to 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 utilized for the analysis of an extensive range of volatile organic compounds (VOCs). The proprietary Vocus PTR Reactor decreases wall losses and concentrates ions with radiofrequency (RF) fields to provide users with the lowest detection limits and maximum sensitivity.

Additionally, the Vocus PTR Reactor has been 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 full volatility range. The flow tube reactor functions at an increased pressure to suppress fragmentation of analyte ions and utilizes small VUV sources to produce both positive and negative reagent ions.

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

Having a range of reactors and reagents, the Vocus CI-TOF offers users the utmost flexibility in aiming for particular compound classes.

Chemical Ionization with Vocus CI-TOF

Image Credit: TOFWERK


The Vocus Aim Reactor aids to remove fragmentation when 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. Each of these has been improved 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 exchange of Vocus reactor hardware in the absence of venting (S, Models 2R, and Scout).
  • Library of detectable compounds.
  • Tofware data post processing.
  • Thuner software. Automatic mass spectrometer tuning software.
  • Touch screen control
  • Shipping container. deployment with no disassembly required.
  • Vocus acquisition and control software.
    • Availability of automated gas calibration and zeroing with programmable cycling
    • Single-click transitions can be performed between ready, shutdown, and sleep states
    • Real-time reporting of calibrated concentrations available for target compounds