Fusion UV/Persulfate

The Fusion is a meticulously crafted instrument tailored for the precise determination of carbon content in diverse liquid solutions, with a primary focus on water analysis. Its operation hinges on a secure and established methodology that harnesses UV-promoted persulfate oxidation to convert carbonaceous materials into carbon dioxide (CO2). The Fusion’s exceptional sensitivity spans an impressive range, from 0.2 parts per billion carbon (ppbC) to 4,000 parts per million carbon (ppmC). What truly sets it apart is its capacity to differentiate between various carbon forms through the selection of predefined instrument methods.

The instrument offers four distinct modes of carbon analysis:

1. Total Carbon (TC): This mode quantifies all carbon, whether organic or inorganic, present in the sample.
2. Inorganic Carbon (IC): It specifically determines the inorganic carbon content within the sample.
3. Total Organic Carbon (TOC): TOC analysis calculates the total organic carbon content by subtracting IC from TC.
4. Non-Purgeable Organic Carbon (NPOC): NPOC, also known as TOC by sparging, employs a specialized process involving precise sample and reagent transfer for accurate measurement.

For TOC determination using the NPOC method, the Fusion employs a sophisticated setup, including a syringe driver and a 7-port valve. This ensures the precise transfer of samples and reagents to the reactor. The process involves a sequential transfer of the resulting CO2 from the sample to either vent or the NDIR detector. This sequence unfolds meticulously:

1. IC and POC Removal: Initially, IC and POC are removed through acidification and sparging within the IC sparger.
2. UV Reactor Oxidation: Following IC removal, a portion of the sparged sample is transferred to the UV reactor. Here, persulfate reagent is introduced to facilitate the oxidation of organic carbon. This oxidation proceeds through a series of chemical reactions, including the formation of free radical oxidants, excitation of organics, and their subsequent oxidation.
3. NDIR Detection: The oxidation products generated in Step 2 are efficiently channeled into the CO2-selective NDIR detector.

A critical aspect of this process is the closure of the exit valve from the NDIR, allowing the detector to pressurize. Once the gases within the detector reach equilibrium, a precise analysis of CO2 concentration ensues. This pressurization, termed Static Pressure Concentration, significantly enhances sensitivity and precision. It facilitates the measurement of all oxidation products within the sample during a single reading, setting it apart from conventional flow-through technology. The resulting output signal is directly proportional to the concentration of CO2 resulting from sample oxidation.