The RF focusing fields in the Vocus ion molecule reactor improve sensitivity while maintaining product ion energies and recorded branching ratios that are nearly identical to those of traditional drift-tube PTR ion-molecule reactor designs.
The Vocus PTR-TOF offers unmatched sensitivity and mass resolving power for online detection of VOCs
A proton transfer reaction mass spectrometer (PTR-MS) with sub-ppt limits of detection and mass resolving power up to 15000
Announcing Improved Vocus PTR-TOF Performance and a New Model for Online VOC Monitoring
Advantages of the Vocus PTR-TOF
The Vocus PTR-TOF is a proton transfer reaction mass spectrometer (PTR-MS) for sensitive, real-time detection of volatile organic compounds (VOCs) in industrial, laboratory, and field applications.
- Ultra-Low Limits of Detection. High sensitivity and low backgrounds combine to yield sub-ppt VOC limits of detection in seconds
- Highest Available Mass Resolving Power. Mass resolving power up to 15000 enables identification of isobaric compounds in complex mixtures
- Mobile Measurement. Compact, durable architecture brings laboratory-grade performance to vehicle and aircraft-based measurements
- Adaptable for Your Applications. Work with us to integrate the Vocus PTR-TOF into your existing sampling systems and workflows
- Intuitive, Powerful Software. Easy-to-use data acquisition interface and Tofware graphical post-processing software for the analysis of high-resolution TOF data
- Revolutionary PTR Reaction Cell Design. The proprietary Vocus reaction cell reduces wall losses and focuses ions to give you up to 10x the sensitivity of other commercial PTR-MS. Learn more about the Vocus technology
Improving PTR-MS without Compromise
The unique Vocus ion molecule reactor (IMR) improves almost all aspects of PTR-MS performance, while maintaining critical specifications and reaction processes that have been established for conventional designs.
These fundamental aspects of Vocus PTR-TOF performance are key to its fast, ultra-sensitive measurement of trace VOCs.
Vocus PTR-TOF mass spectra are dominated by protonated peaks and free of significant contributions from non-PTR reaction and therefore easily interpreted and quantified.
The Vocus PTR-TOF routinely detects a very large number of VOCs, including many for which standards are not available. It is possible to calibrate for all detected compounds with good accuracy based on simple measurements of a small number of VOC standards.
Select a Vocus Model to Meet Your Measurement Needs
|Sensitivity cps/ppb xylene||Limit of Detection (LOD) 1-min / 1-s, xylene||Resolving Power at Specified Sensitivitya M/ΔM||Maximum Resolving Powera M/ΔM||Size||Power Max / Typical|
|2R||30001||1 ppt / 10 ppt||10000||15000||160 kg < 0.45 m3 480 x 615 x 1480 mm||600 / 590 W|
|S||30001||1 ppt / 10 ppt||5000||7000||120 kg < 0.35 m3 480 x 615 x 1130 mm||600 / 590 W|
|Scout||4000||5 ppt, 1 min||3500||4000||120 kg < 0.35 m3 480 x 615 x 1130 mm||600 / 590 W|
|Elf||500||20 ppt, 1 min||500||750||55 kg < 0.125 m3 380 x 500 x 650 mm||450 /400 W|
a. Each model can be operated with higher resolving power at reduced sensitivity.
- Standby Valve. Allows servicing of Vocus reaction cell hardware without venting (Models 2R, S, and Scout).
- Tofware Data Post Processing.
- Library of Detectable Compounds.
- Thuner Software. Automatic mass spectrometer tuning software.
- Touch Screen Control.
- Shipping Container. Deployment with no disassembly required.
- Acquility Data Acquisition and Instrument Control Software.
- Automated gas calibration and zeroing with programmable cycling
- Real-time reporting of calibrated concentrations for target compounds
- Single-click transitions between shutdown, ready, and sleep states
- Reagent Ion Switching. An expanded suite of reagent ions increases chemical scope and specificity.
- Liquid Calibration System (LCS). Direct calibration of instrument response using aqueous standards.
- Fast GC. GC separation before Vocus PTR-TOF increases experiment resolution and separate isomeric species.
- Headspace Autosampler. Coupling Vocus PTR-TOF to headspace autosampler for high throughput analysis. Watch Video
- Vocus Aerosol Inlet. Online analysis of the molecular composition of aerosols with Vocus PTR-TOF.
- Interchangeable Ion Sources. Easy interchange of ion sources with our API-TOF platform.
- Permeation Source. Continuous internal mass calibration.
Vocus Reaction Cell and Sampling Inlet
- Proprietary reagent ion source and ion-molecule reaction cell with axial DC field and RF-focusing.
- Automated reagent ion switching.
- Temperature controlled reaction cell, ambient temperature up to 120C.
- Heated inlet system, up to 180 C.
|Sample Flow Rate||50-500 sccm typical 100 sccm|
|Operating Pressure||0.5 – 5 mbar typical 1-2 mbar|
|Axial Gradient||Uniform linear field 0-5 V/mm|
|Reagent Ions||H3O+, NO+,O2+, NH4+|
Vocus PTR-TOF Publications
- Claflin, M. S. et al. An in situ gas chromatograph with automatic detector switching between Vocus PTR-TOF-MS and EI-TOF-MS: Isomer resolved measurements of indoor air. Atmos. Meas. Tech. Discuss. In review 2020. DOI:10.5194/amt-2020-271
- Mehra, A. et al. Evaluation of the chemical composition of gas- and particle-phase products of aromatic oxidation. Atmos. Chem. Phys. 2020. DOI: 10.5194/acp-20-9783-2020
- Bruderer, T. et al. Detection of Volatile Organic Compounds with Secondary Electrospray Ionization and Proton Transfer Reaction High-Resolution Mass Spectrometry: A Feature Comparison. J. Am. Soc. Mass Spectrom 2020. In Focus | DOI: DOI: 10.1021/jasms.0c00059
- Li, H. et al. Source identification of atmospheric organic vapors in two European pine forests: Results from Vocus PTR-TOF observations. Atmospheric Chemistry and Physics In review 2020. DOI: 10.5194/acp-2020-648
- Wang, Y. et al. Detection of gaseous dimethylamine using Vocus proton-transfer reaction time-of-flight mass spectrometry. Atmospheric Environment 2020. DOI: 10.1016/j.atmosenv.2020.117875
- Wang, Y. et al. Oxygenated products formed from OH-initiated reactions of trimethylbenzene: Autoxidation and accretion. Atmospheric Chemistry and Physics 2020. DOI: 10.5194/acp-20-9563-2020
- Li, H. et al. Terpenes and their oxidation products in the French Landes forest: insight from Vocus PTR-TOF measurements. Atmospheric Chemistry and Physics 2020. In Focus | DOI: 10.5194/acp-20-1941-2020
- Holzinger, R.; et al. Validity and limitations of simple reaction kinetics to calculate concentrations of organic compounds from ion counts in PTR-MS. Atmos. Meas. Tech. Discuss 2019. DOI: 10.5194/amt-12-6193-2019
- Riva, M.; Rantala, P.; Krechmer, J. E.; Peräkylä, O.; Zhang, Y.; Heikkinen, L.; Garmash, O.; Yan, C.; Kulmala, M.; Worsnop, D.; and Ehn, M. Evaluating the performance of five different chemical ionization techniques for detecting gaseous oxygenated organic species. Atmos. Meas. Tech. Discuss 2018. In Focus | DOI:10.5194/amt-12-2403-2019
- Krechmer, J.; Lopez-Hilfiker, F; et al. Evaluation of a New Vocus Reagent-Ion Source and Focusing Ion-Molecule Reactor for use in Proton-Transfer-Reaction Mass Spectrometry. Analytical Chemistry 2018. In Focus | DOI: 10.1021/acs.analchem.8b02641
- PDF - Real-Time Breath Analysis for Pharmacokinetics Using the Vocus CI-TOF
- PDF - Chemical Fingerprinting of Olive Oil Aroma
- PDF - Automated, Rapid Profiling of Trace Compounds in Complex Chemical Headspace Using the Vocus PTR-TOF
- PDF - Separation and Quantification of Trace Chemical Emissions from Packaging Materials Using the Vocus PTR-TOF
- PDF - Time-Resolved Organic Polysulfides Analysis Using the Vocus PTR-TOF
- PDF - High-Throughput Analysis of VOCs From Electronic Waste Emissions
- PDF - Lung Uptake of Indoor Air Pollutants
- PDF - Inside a Consumer’s Nose: Nose-Space Analysis Using the Vocus PTR-TOF
- PDF - Indoor Air Quality Monitoring at an Industrial Facility
- Point Source Detection and VOC Emissions Fingerprinting in Chinese Megacities
- Spatial Characterization of VOC Emissions with a Mobile Vocus Elf
- PDF - Realtime Chemical Analysis of Illicit Drugs
- PDF - Online Profiling of Fish Oil Oxidation Byproducts
- Realtime Detection of the Explosives TATP and HMTD
- PDF - Rapid Quantification of Brett Off-Flavor Compounds in Wine
- PDF - Fast Analysis of Beer Aroma – GC-PTR-MS
- PDF - Rapid, Sensitive Fentanyl Detection by Thermal Desorption PTR-MS
- PDF - Monitoring Trace VOCs in Human Breath Emissions with PTR-MS
- High-Throughput Monitoring of Plant VOC Kinetics with a Novel Autosampler and the Vocus PTR-TOF - View Video
- PDF - Identification of Isobaric VOCs in Coffee Aroma with High Resolution PTR-MS
- PDF - Puff-By-Puff Analysis of E-Liquid Components, Flavor Compounds and HPHC in E-Cigarette Vapor Using the Vocus PTR-TOF
- PDF - A New PTR-MS Reaction Cell Combining Linear and Oscillating Fields (EMSC 2018)
- (VIDEO) French TV News Highlights COVID Detection Using the Vocus PTR-TOF
- Resolving Isomers in Indoor Air Using GC Combined with Detector Switching
- Vocus PTR-TOF Excels in Field Study of Atmospheric Oxidation Processes
- Vocus PTR-TOF 2R Excels in Measurements of Highly Oxygenated Compounds
- Profiling Oil and Gas Well Emissions with Mobile PTR-MS
- Vocus PTR-TOF Participates in Joint Study for Disease Diagnosis Via Breath Analysis
- Characterization of the Vocus PTR-TOF: Analytical Chemistry
- Webinar: Real-Time Breath Analysis With the Vocus CI-TOF
- PDF - Webinar: Real-Time Mobile VOC Monitoring with the Vocus PTR-TOF
- Vocus PTR-TOF Webinar: Fundamentals and Applications - View Video
- PDF - Product Ion Energies and Branching Ratios in the Vocus Ion-Molecule Reactor
- PDF - High Purity H3O+ Reactant Ions Enable Simple Interpretation of Vocus PTR-TOF Data
- PDF - Calibrating Vocus PTR-TOF Sensitivity Using a Subset of VOC Standards
- PDF - Ultra-Fast Time Response with the Vocus PTR-TOF
Background Knowledge About Vocus PTR-TOF
Practical Implications of High Sensitivity in Mass Spectrometry The video below uses the example of detecting trace levels of the compound TCA in cork wine
Proton Transfer Reaction – Mass Spectrometry (PTR-MS) is the most widely used method for real-time monitoring of volatile organic compounds (VOCs) at low concentrations Key
Volatile organic compounds (VOCs) are ubiquitous chemicals that play a significant role in many systems, including health, the environment, food, and industry. Characterization of VOCs can be complicated because they are often trace constituents within complex mixtures. The Vocus PTR-TOF offers unprecedented performances for real-time identification and quantification of VOCs in all fields. The following examples illustrate the instrument’s key advantages. Contact us to discuss other applications or request a demonstration with your samples.