Portable GC-MS DW-EXPEC3500S Gas Chromatography-Mass Spectrometer

The DW-EXPEC3500S Portable GC-MS is based on gas chromatography-mass spectrometry (GC-MS) technique for the analysis of organic pollutants in the field. It can be equipped on a mobile carrier for monitoring, or can be moved over the shoulder or handheld to sites that are inaccessible by car for rapid qualitative and quantitative analysis of volatile and semi-volatile organic chemical contaminants.

The DW-EXPEC3500S Portable GC-MS uses a single mass spectrometer membrane injection technique, gas chromatography separation technique and ion trap mass spectrometry technique. After passing through the pre-treatment equipment, the sample is fed through a chromatographic injection system or a membrane injection system and then into a mass analyzer to be tested to obtain the qualitative and quantitative results of the sample.

The DW-EXPEC3500S Portable GC-MS consists of an injection system, a gas chromatography module, a gas-mass interface and a mass spectrometry module. The principle of operation is shown in Figure 1: the sample enters the chromatographic separation module through the injection system, where the sample is separated; the separated sample then enters the mass spectrometry module in turn for analysis, and finally the qualitative and quantitative results are obtained through data processing.

Figure 1Block Diagram of DW-EXPEC3500S Operating Principle
Figure 1Block Diagram of DW-EXPEC3500S Operating Principle

Features of Portable GC-MS DW-EXPEC3500S Gas Chromatography-Mass Spectrometer

As a new portable GC-MS, the DW-EXPEC3500S not only features a stable and reliable instrument with high environmental adaptability, but also has the advantages of fast analysis speed, high sensitivity, high contamination resistance and a wide range of injection methods.

  1. Fast analysis speed: in addition to the separation efficiency of fast chromatography being 5 times higher than that of conventional chromatography, the membrane injection technique allows the sample to enter the mass spectrometry directly without passing through the chromatography, reducing the response time to seconds, making it very suitable for rapid screening.
  2. A wide range of testing options: with injection modes such as direct mass spectrometry injection, sorptive thermal desorption injection, quantitative ring injection, headspace injection, needle injection and solid phase microextraction injection, covering all the current sample introduction modes on portable GC-MS applications, it enables fast mass spectrometry with second response, ambient air detection at low concentrations, pollution source detection at high concentrations, VOCs and SVOCs detection in water and soil.
  3. Environmental adaptability: the instrument can operate at -5°C to 45°C and a low air pressure of 54kPa; it is also waterproof to IP55.
  4. Easy software operation: intelligent wizard-based operation for sample testing and data analysis, greatly reducing training costs and complexity of field use.
  5. The ion trap’s unique multi-stage mass spectrometry scan mode: SIS scans and MS/MS scans can be performed on substances of interest, which can greatly increase detection sensitivity and reduce false positives.

Specifications of Portable GC-MS DW-EXPEC3500S Gas Chromatography-Mass Spectrometer

Performance indexesMass range(15~550) amu
ResolutionBetter than 1amu
Injection modeSoftware switchable single mass spectrometry injection, GC-MS internal standard sorbent tube injection, GC-MS internal standard quantitative ring injection
Scanning modeFull Scan, Selective Ion Monitoring (SIM) and Secondary Mass Spectrometry (MS/MS) scanning modes are available
SensitivitySingle mass spectrometric injectionToluene (5mg/m3) S/N: ≥10
GC-MS sorbent tube injectionToluene (10ppb) S/N: ≥50
GC-MS split inlet injectionOctafluoronaphthalene (100 pg/μL): S/N≥15 (272amu)
Single mass spectrometry response timeToluene 1 ppm: ≤30s; second response time
Single mass spectrometry recovery timeToluene 1 ppm: ≤30s; second recovery to reduce the impact on the next sample
Dynamic range107
Ion sourceEI source, ionisation energy 70eV
DetectorElectron multiplier tube
Quality analyzerIon trap mass analyzer
Main unit weight≤20kg (including gas cylinder and battery)
System volume44cm×43cm×22cm
Anti-vibration gradeMeets the requirements of GJB150.16A-2009
Waterproof gradeMeets IP55
Vacuum≤3000 μTorr
Automatic tuningThe instrument can be automatically calibrated on the mass axis of the main unit
Calibration functionThe internal standard can be added automatically and in real time during the analysis of the sample to achieve the calibration function of the internal standard.
Pre-sampling functionEnsure that each analysis is not affected by the dead volume of the sampling line
Blowback functionEnsure that the residue of the sorbent tube after each analysis does not affect subsequent analyses
Carrier gasHelium gas in a carrier gas bottle built into the main unit
Sampling flowSampling flow is controlled electronically and adjustable
Operating parametersPower supply220VAC±10% / 50HZ, or rechargeable battery
Environmental temperature-5 to 45°C
Storage temperature-20~70°C
Relative humidity(0%~95%) RH
Ambient pressureMay be used in highland areas.54 kPa~101.3 kPa
External communicationPositioning systemGPS, BeiDou dual-mode system, switchable; real-time positioning of the sample testing site
Communication modeLAN
SoftwareDatabaseNIST Standard Spectrum Library
Automated mass spectral deconrolution and identification system (AMDIS)
National Institute for Occupational Safety and Health (NIOSH) Database
Instrument Specific Spectrum Library for Environmental Samples
Safety Instructions of Chemicals (SIC)
Environmental Standards Reference Database
Data acquisitionBuilt-in IPC with touch screen human-machine interaction;
Data processingBuilt-in IPC; human-machine interaction: touch screenExternal PC;  human-machine interaction: keyboard and mouse