Ambient Air Quality Monitoring
Gas Chromatography Volatil Organic Compounds (BTEX) Analyzer
The VOC72M’s metrology, in accordance with EN 14662-3 standard for benzene measurement, is based on gas chromatography (GC) for the separation of the measured compounds coupled with a photo-ionization detector (PID). This compact and fully automated analyser provides equal performance to the laboratory chromatographs and is particularly well-suited for fixed or mobile ambient air quality monitoring stations.
NEW: on board web server compatible with any internet browser. [email protected]
™ user interface with on-line help for the display, configuration, maintenance, diagnostics or software updating of the analyser, remotely, from any PC, tablet or iPhone.
TCP/IP remote control with dynamic, multilingual interface, featuring intuitive navigation by pictograms.
Standard measured compounds: Benzene, Toluene, Ethylbenzene, m+p-Xylene, o-Xylene, 1-3 Butadiene... P erforms all the functions, such as: sampling, analysis and data management, in a simple and completely autonomous mode R obust and low maintenance instrument, (no PID lamp cleaning) R eady to use in less than 30 minutes Quick check of the chromatogram peaks possible directly on-screen, without the use of a computer Memory effect (up to 10 times lower than required by the standard EN14662-3) allowing the automatic calibration of the analyser on a single cycle without an external PC G C column equipped with an innovative liquid-cooler; retention times are stable even with a fluctuating temperature U ltrafast trap heater (heating rate >160°C/second) Remote diagnosis, made possible without opening the hood Replacement of the trap in less than 2 minutes. No adjustment required Use of a single gas source (nitrogen) 3 levels of built-in security Equipped with LCD screen High sensitivity, stable and linear response PID detector Long-life capillary column Self-contained and completely automated Synoptic flow diagram display TUV certified to VDI 4202-1: 2010, VDI 4203-3: 2010, EN 14662-3: 2005, EN 15267-1: 2009 and EN 15267-2: 2009
MAIN APPLICATIONS: • Ambient air monitoring • Monitoring of industrial sources emitting VOCs • Photochemical pollution studies (stationary and mobile laboratories)
Gas Chromatograph BTEX Analyzer VOC72M OPERATING PRINCIPLE:
Ethylbenzene, m+p-Xylene, o-Xylene, 1,3 Butadiene (other compounds on request) Winchrome software for chromatograms retrieval, instrument maintenance and diagnostics Measuring ranges: maximum 1000 µg/m3 (programmable) Units: ppb or µg/m3 (programmable) Cycle duration: 10, 12, 15, 20, 30 minutes(progr.) Measuring noise (s): ≤0.025µg/m3 at 0.5µg/m3 benzene Lower detectable limit (2s): ≤0.05µg/m3 benzene Carry-over (memory effect): ≤0.5% on the first zero Long-term span drift: ≤4% on 15 days Lack of fit; largest residual: ≤4% of the measured value Repeatability standard deviation: ≤0.05µg/m3 at 5µg/ m3 benzene (<1% of the annual limit) Sample flow: 50ml/minute Specifications are based on 15 min cycle. Flow control: integrated vacuum pump + heated micro capillary tube Trap adsorbent: Carbopack® Sampling temperature: 35°C Desorption temperature / heating rate: 380°C (programmable) / > 160°C/second Injection valve: 6-port (heated) GC column: stainless steel 15m x 0.25mm x 1µm apolar • Carrier gas control: electronic pressure control • Temperature control: 20-170°C ± 0.1°C 5 ramps up to 30°C/minute. • Cooling: liquid heat exchanger and thermo-electric cooler GC detector: Photo-ionisation (PID) 10,6eV with nitrogen curtain Detector's temperature: 140°C (programmable) Display: LCD 240 x 128 text and graphic mode Ethernet port: RJ45 socket, UDP protocol USB port: USB socket format 1.0 Dimensions: (LxWxH): 601 mm x 483 mm x 133 mm Weight: 12.5 kg Electrical consumption: average: 130VA, peak 200VA, stand-by 50VA Power supply: 100–240V + ground; 50–60Hz Operating temperature: + 5°C to + 35°C
OPTIONS: ESTEL 2 maximum electronic boards with: 4 independent analog inputs (0-2.5 V) / outputs (0-1 V, 0-10 V, 0-20 mA, 4-20 mA), 4 remote control inputs, 6 dry contacts Gas supply: Nitrogen 6.0 (99.9999%) 3.2 ± 0.2 bar 15 ml/minute RS232 or RS422 serial interface (max. one Estel board if this option is used) Span gas solenoid valve
The VOC72M performs three main functions: the sampling, the GC analysis and the data processing.
Sampling: The sampling is achieved with a single trap filled with a specific sorbent. Its flow through the trap is about 12 ml/min which gives a sampled volume of 165 ml with the standard 15 minute cycle (sampling time >90% of cycle time). Other cycle durations are possible from 10 to 30 minutes. A bypass flow of 35 ml/min is added in order to maintain a sample input flow when the trap is not sampling.
GC analysis: At the end of the sampling cycle, the trap is connected to the GC column and quickly heated (35 to 380°C within 2 seconds). The compounds are thermally desorbed and flushed with nitrogen into the GC column. Then the trap is fastly cooled with a fan for a new sampling cycle. Inside the GC column, the compounds are moved forward by the nitrogen flow (the mobile phase) and retained by the internal coating (the stationary phase) causing a selective retardation of the compounds. In order to achieve an optimal separation within a minimal time, the GC column follows a multi ramp thermal cycle from a cold step (25°C) for the injection to a hot step (160°C) for flushing all the heavy compounds (i-e compounds with a high boiling point). At the end of the hot step, the GC column is cooled to the cold step for the next injection. The GC column output is connected to a photo ionization detector where the compound concentration is converted into a small electric signal. This signal is amplified and digitized in the electrometer board. The time recording of this signal gives the chromatogram which exhibits a peak for each detected compound. An ambient air chromatogram may include over 100 peaks.
Data processing: The ARM7 board processes the chromatogram. The peaks are detected and integrated with a baseline correction. The peak timing (retention time) is also recorded. When a peak retention time falls into a compound retention time window (typically ± 2 seconds), this peak is identified as the compound. The peak area is corrected with a volume calculation (based on the trap pressure during the sampling) and the atmospheric pressure compensation for the detector response. The corrected area, multiplied by the compound response factor, gives the compound’s concentration.
6-port injection valve
Micro capillary restrictors
111, Bd Robespierre – CS80004 78304 Poissy Cedex 4 - FRANCE Tel. : +33(0)1 39 22 38 00 Web: www.environnement-sa.com E-mail: [email protected]
GC column plate
(heated or cooled)
Typical specifications subject to changes without prior notice.
6 measured compounds: Benzene, Toluene,
VOC72M_EN_PSO - InDes -052014