VOC Sampling Device Using Purge Gas Extraction for In-Situ Water Analysis
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Solution Overview
Problem
Conventional methods for detecting volatile organic compounds (VOCs) in water are inefficient, unreliable, and inconvenient for in-situ monitoring, as they require laboratory analysis and complex processes that can alter the water sample components, leading to inaccurate results and high costs.
Innovation Solution
A sampling and detection device with a hollow sampler, gas bubbler, gas detector, and closed-loop gas pipeline system that uses a purge gas to extract VOCs from water, allowing for direct in-situ detection without removing the water sample, ensuring precision and continuity of measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sampling methods are used to collect water samples for VOC detection, then the samples can be brought to the laboratory for analysis, but the components of the water body change during the time interval between sampling and testing, leading to inaccurate results
Solution Approach 1:
The device performs preliminary extraction of VOCs from water into a gas phase within the sampler before transport. The extraction tube with adsorbent material pre-concentrates the volatile compounds, so that when the sample is later analyzed, the VOCs are already prepared in a detectable form, eliminating the need for time-consuming laboratory extraction procedures and preserving the original water matrix composition.
Solution Approach 2:
An extraction tube containing adsorbent material serves as an intermediary between the water sample and the detection instrument. This intermediary selectively captures VOCs from the water while leaving the bulk water matrix unchanged, allowing for stable, time-independent transport and analysis without altering the original sample composition.
2Measurement precision
If laboratory extraction and enrichment methods are used for VOC analysis, then comprehensive component analysis can be achieved, but the processes are complicated and time consuming
Solution Approach 1:
The device merges the sampling, extraction, enrichment, and detection functions into a single integrated portable system. The extraction tube with adsorbent material combines extraction and concentration functions, while the connected detection instrument performs analysis in-field, eliminating the need for separate laboratory equipment and complex multi-step procedures.
Solution Approach 2:
The invention extracts only the essential functions needed for VOC detection from the complex laboratory procedure suite. By using a pre-filled extraction tube with specific adsorbent material, it isolates the critical extraction and enrichment steps from the water sample, leaving behind the complicated laboratory instrumentation and procedures.
3Productivity
If portable detection instruments are used for in-situ VOC detection, then quick on-site analysis can be performed, but the measurement accuracy is undesirable and the instrument cost is high
Solution Approach 1:
The device performs preliminary concentration of VOCs onto the adsorbent extraction tube in the field before analysis. This pre-concentration step ensures that even trace levels of VOCs are sufficiently concentrated for accurate detection by the portable instrument, achieving laboratory-quality accuracy with field-portable equipment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient, quick, and reliable detection of VOCs in water, maintaining accuracy and reducing the risk of sample alteration, with a detection limit as low as the µg/L level, suitable for real-time monitoring of water pollution.
Implementation Method 1
enrichment (e.g., as disclosed in US patent application US2001/0003426A1) or purging-and-trapping methods
Implementation Method 2
The US patent US5448922 discloses a gas permeation system which also uses a gas permeation membrane
Implementation Method 3
VOCs in the water permeate or diffuse through the polymer membrane and are brought out by a dilution gas stream for detection
Implementation Method 4
VOCs in the water permeate or diffuse through the polymer membrane
Implementation Method 5
The gas detector is selected from the group consisting of a photoionization detector, a thermal conductivity detector, a hydrogen flame detector, an ion mobility detector, a mass spectrometry detector and a spectral detector
Data Source
Figure 1~2
Figure 3
AI summary
The present invention discloses a sampling and detection device for detecting volatile organic content in water, comprising a hollow sampler (3) and a gas detector (2) connected to the sampler (3). A side wall of a lower half of the sampler (3) is provided with more than one water inlet channel (1), and a lower end is provided with a gas bubbler (10). Said detection device ensures measurement accuracy and continuity while facilitating in-situ detection.