The Total Organic Carbon (TOC) analyzer is a key tool for monitoring organic pollutants in water bodies, soils, and industrial processes. Its technical core is to quantitatively convert organic matter into carbon dioxide (CO ₂) and infer the total organic carbon content by detecting the concentration of CO ₂. The mainstream technological routes are divided into combustion oxidation method and ultraviolet oxidation method:
Combustion oxidation method
By high-temperature (680-900 ℃) combustion, organic matter in the sample is oxidized to CO ₂ under the action of ceramic catalytic oxidation tubes. This method has high oxidation efficiency and is suitable for high concentration organic matter samples (such as industrial wastewater), but it may cause salt containing samples to clog or corrode components due to high temperatures.
UV oxidation method
Utilizing the synergistic effect of 185nm ultraviolet radiation and hydrogen peroxide/ozone to achieve organic matter oxidation at low temperatures. The advantage lies in the absence of high-temperature components and the ability to analyze high salt or corrosive samples (such as seawater), but the oxidation efficiency of complex organic compounds (such as aromatic hydrocarbons) may be limited.
Core detection method
The CO ₂ generated by oxidation is quantified using the following techniques:
Non dispersive infrared detection (NDIR): Concentration measurement is carried out through the characteristic absorption peak of CO ₂ at a wavelength of 4.26 μ m. It has high sensitivity and strong anti-interference ability, and is the mainstream detection method.
Conductivity detection: Suitable for ultrapure water or low concentration samples, the detection is achieved by measuring the change in conductivity caused by the dissolution of CO ₂ in water, but requires frequent calibration.
Membrane conductivity method: Selective separation of CO ₂ through a semi permeable membrane for detection, suitable for high humidity or complex gas samples.
technical advantage
TOC analyzer has the characteristics of strong real-time performance, high sensitivity (detection limit up to μ g/L level), and automated operation, and is widely used in pharmaceutical water monitoring, industrial wastewater discharge compliance testing, and semiconductor cleaning process control. Its core value lies in rapidly assessing the degree of organic pollution, providing data support for water quality management, process optimization, and environmental supervision.