Precise, stable CO2 isotope measurements
The LI-7825 measures the four most abundant CO2 gas isotopologues in air and reports δ13C , δ17O , and δ18O with high precision and accuracy. By measuring CO2 isotopologues and calculating isotope ratios, researchers can:
- Identify the sources and sinks of atmospheric carbon
- Partition net ecosystem carbon exchange
- Gain insight into biological processes
- Evaluate carbon sequestration efforts
Backed by over thirty-five years of experience in gas analysis technology, the LI-7825 joins the LI-COR Trace Gas Analyzers trusted by researchers and networks around the world.
Dependable, accurate, portable, and affordable
The LI-7825 features the same rugged design, portability, accuracy, and precision as other LI-COR Trace Gas Analyzers at an affordable price. Suitable for both the bench and the field, it is easily added to an existing instrument rack. It can integrate into established systems and delivers dependable data to allow researchers to ask and answer new questions with confidence.
Key specifications
General
- Total Weight: 10.5 kg (including batteries)
- Battery Life: 8 hours typical with 2 batteries
δ13C Measurements
Precision (1σ):
- <0.5 ‰ with 1 second averaging
- 0.04 ‰ with 5-minute averaging
Maximum Drift: <1 ‰ per 24-hr period
Applications
- Atmospheric monitoring
- Urban emissions monitoring
- Mobile emissions monitoring
- Large area emissions monitoring
- Sensor networks
- Mud gas logging
More applications information coming soon.
Measuring atmospheric CO2 isotopologues
The LI-7825 meets or exceeds requirements for long-term atmospheric background measurements and offers a versatile platform for a range of applications for a better understanding of CO2 emissions from anthropogenic and natural sources.
Measuring NH3
The LI-7825 measures higher concentrations of NH3, and is suitable for detecting ammonia in livestock barns, feedlots, barnyards, fertilizer applications, fence line monitoring, ammonia leaks, and other applications where NH3 concentration is elevated above natural abundance.
While the analyzer provides accurate NH3 measurements of the air reaching the sample cavity, users will need to account for the adsorption of NH3 to the sampling equipment in soil gas flux systems.
NH3 measurements are not supported for LI-COR soil gas flux systems.
LI-7825 Specifications
General
- Measurement Technique: OF-CEAS (Optical Feedback – Cavity Enhanced Absorption Spectroscopy)
- Measurement Rate: 1 sample per second (1 Hz)
- Optical Cavity Volume: 6.41 cm3
- Flow Rate:
- 250 sccm nominally for Standard Configuration
- 70 sccm nominally for Reduced Flow Rate Configuration with installed kit
- Total Weight: 10.5 kg (including batteries)
- Case Dimensions: 51 cm × 33 cm × 18 cm (L × W × H)
- Operating Temperature Range: -25 ℃ to 45 ℃ (without solar load, under normal operating conditions.)
- Operating Humidity Range: 0 to 85℅ RH (non-condensing, without solar load, under normal operating conditions)
- Sample Line Humidity Range: 0 to 99℅ non-condensing
- Operating Pressure Range: 70 to 110 kPa
- Connectivity: Ethernet and Wi-Fi (not available in some countries)
- Wi-Fi Compatibility: 2.4 GHz, 802.11 a/b/g/n/ac
- Power Consumption:
- Steady State Operation: 22 Watts at 25 ℃ without batteries charging
- Warmup: up to 65 Watts without batteries charging; up to 100 Watts with batteries charging
- Off: Up to 2.3 Watts when powered from pins 3 and 4 without batteries charging; up to 0.2 Watts when powered from pins 1 and 5 without batteries charging
- Power Supply Requirements:
- Pins 1 and 5 (24 VDC Input): Minimum 6 A at 24 V
- Pins 3 and 4 (10.5 to 33 VDC Input): Minimum 14 A at 10.5 VDC; 6 A at 24 VDC
- Battery Life: 8 hours typical with 2 batteries
- Pollution Degree: 2
- Over-voltage Category: II
- Class 1 Laser Product
- CO2 Measurements
- Range: 50 to 2,000 ppm
- Precision (1σ): <0.05 ppm at 400 ppm with 5-minute averaging
- Response Time (T10-T90): ≤2 seconds from 0-400 ppm
- Maximum Drift: <0.5 ppm per 24-hour period
- δ13C Measurements
- Precision (1σ):
- <0.5 ‰ with 1 second averaging
- 0.04 ‰ with 5-minute averaging
- Maximum Drift: <1 ‰ per 24-hour period
- δ18O Measurements
- Precision (1σ): <0.1 ‰ at 400 ppm with 5-minute averaging
- Maximum Drift: <4 ‰ per 24-hour period
- δ17O Measurements
- Precision (1σ): <0.4 ‰ at 400 ppm with 5-minute averaging
- Maximum Drift: <12 ‰ per 24-hour period
- NH3 Measurements
- Range: 0 to 30,000 ppb
- Precision (1σ): 2 ppb at 300 ppb with 1 second averaging
- Response Time (T10-T90): ˜5 minutes*
- H2O Measurements
- Range: 0 to 60,000 ppm
- Precision (1σ):
- 45 ppm at 10,000 ppm at 1 second
- 20 ppm at 10,000 ppm with 5 second averaging
*NH3 measurement response time is dependent upon gas composition and inlet pneumatic configuration including tubing/fitting materials, flow rates, and upstream volumes.
Specifications subject to change without notice.
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