How do TOC Analyzers work?
A TOC analyzer converts all organic carbon in a water sample to CO2 and quantifies the gas. Two oxidation routes dominate. High-temperature catalytic combustion injects the sample into a furnace at 680–900 °C containing a platinum or similar catalyst, which also handles particulates and difficult compounds. UV-persulfate oxidation adds sodium persulfate and irradiates the sample with UV at 185 and 254 nm to generate hydroxyl radicals. Inorganic carbon is removed first by acidification and sparging, or measured separately to give TOC by difference. The CO2 is carried by purified air or oxygen to a non-dispersive infrared detector, or measured by membrane conductometry in low-level systems. Peak area is integrated and converted to concentration using a multi-point calibration against potassium hydrogen phthalate standards.
Which TOC Analyzers variants are available?
- High-Temperature Combustion TOC Analyzer for Wastewater — A laboratory TOC analyzer that catalytically combusts wastewater samples at up to 900 °C and detects CO2 by NDIR.
- UV-Persulfate TOC Analyzer for Drinking Water — A laboratory TOC analyzer that oxidizes organic carbon with UV light and sodium persulfate, offering sub-0.1 mg/L resolution.
- Online TOC Analyzer for Surface Water and Effluent Monitoring — An unattended TOC analyzer installed at river stations, intake works or plant outfalls, reporting organic carbon every 10 to 60 minutes.
- TOC-TN Analyzer for Water Samples with Autosampler — A laboratory analyzer that measures total organic carbon and total nitrogen bound in a single combustion run, using NDIR for CO2 and chemiluminescence for nitrogen oxide.
- Ultrapure Water TOC Analyzer — An online sensor-type TOC analyzer that measures organics in high-purity water down to 0.5 µg/L using UV oxidation and conductivity detection.
How do I choose the right variant?
The decisive parameters are sample matrix, measuring range and operating mode. Wastewater and effluents with particulates, high salt or high carbon load call for high-temperature combustion with a robust injection system and dilution capability. Drinking water and cleaner surface water, typically below 20 mg/L, are well served by UV-persulfate or low-temperature oxidation with sub-0.1 mg/L resolution. Semiconductor and pharmaceutical purified water need online ppb-level sensors with conductivity-based detection. Decide whether you need laboratory batch analysis with an autosampler or continuous online data. If nitrogen loading matters for discharge permits, a combined TOC-TN configuration saves a second instrument. Also check the method you must follow, such as ISO 8245 or USP <643>, and the consumables cost of gases, catalyst and reagents.
Where are TOC Analyzers used?
TOC Analyzers are specified in drinking water treatment monitoring, wastewater discharge compliance, surface water and groundwater surveys, pharmaceutical purified water testing and semiconductor ultrapure water monitoring.
Which standards and certifications apply?
Work with TOC Analyzers is commonly governed by ISO 8245, ASTM D4839, ASTM D5173, ASTM D5904, USP <643>, Ph. Eur. 2.2.44, HJ 501 and IEC 61010-1. Instrument certifications such as CE marking are confirmed per configuration and never assumed.
What are the key considerations before purchase?
Install the analyzer on a stable bench with clean, dry carrier gas at 99.99% purity or a zero-air generator, and provide ventilation for exhaust. Calibrate at least monthly with potassium hydrogen phthalate and verify with sodium carbonate and a blank each run. Keep glassware organic-free and use ultrapure water blanks, since ambient organics cause high blanks. Replace combustion catalyst, halogen scrubbers and persulfate reagent on the schedule stated by the manufacturer. For regulated laboratories, confirm software audit trails and user access levels, and run system suitability with sucrose and benzoquinone to check oxidation efficiency where USP <643> applies.
