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
- Aerosol Inlet. Online analysis of the molecular composition of aerosols with Vocus PTR-TOF.
- Breath Inlet. Real-time measurement of VOCs in human breath.
- 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
- Interchangeable Ion Sources. Easy interchange of ion sources with our API-TOF platform.
- Liquid Calibration System (LCS). Direct calibration of instrument response using aqueous standards.
- Permeation Source. Continuous internal mass calibration.
- Reagent Ion Switching. An expanded suite of reagent ions increases chemical scope and specificity.
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
- Li et al. Overlooked organic vapor emissions from thawing Arctic permafrost. Environ. Res. Lett., 2020. DOI: 10.1088/1748-9326/abb62d
- Wang et al. Characteristics of volatile organic compounds (VOCs) with mobile monitoring around the industrial parks in the Yangzte River Delta region of China. Environmental Chemistry, 2020 (in Chinese). DOI: 10.13227/j.hjkx.202007265
- 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. In Focus | 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. In Focus | 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
- PDF - 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)
- First Field Measurement of Trace Amines Using the Vocus PTR-TOF in China
- (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
- Advantages of Time-of-Flight Mass Spectrometry Over Quadrupole 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 Mass Spectrometer
- 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
The ionization source is a crucial component of a mass spectrometer. The characteristics of the ion source, including the method of ionization, pressure, temperature, and
Time-of-Flight Mass Analyzer A TOF mass analyzer separates ions based on their velocity as they travel through a flight region, often called the flight tube.
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.