Frequently asked questions about different TOC technologies and products.

TOC FAQs

These FAQs relate to TOC Analyzer technologies, capabilities, and performance. For FAQs about a specific Sievers or GE TOC instrument, please click here.

Are the Sievers membrane-based TOC analyzers compatible with pharmaceutical waters containing O3?
The membrane-based technology has a validated ozone compatibility specification of 50 ppb ozone under continuous exposure and 200 ppb ozone for two hours daily. Due to the membrane materials’ compatibility with ozone, the same material is actually used by other instrument manufacturers as part of the analytical process of measuring ozone.
Do the Sievers TOC analyzers monitor UV lamp output to protect data accuracy?
The electrical current level of the UV lamp in Sievers TOC Analyzers is constantly monitored. If the current drops below a specified operating limit, an alarm is triggered. By design, the natural degradation of the lamp does not cause the analyzer to report low TOC levels. When a UV lamp is used within the prescribed lifetime, and considering the active design countermeasures, the design safety factors, the known lamp manufacturing limits, and automated UV lamp monitoring, the probability of lamp failure causing an erroneous TOC result is negligible.
Do Sievers TOC Analyzers completely oxidize the organic molecules in a sample as required by USP<643> and EP2.2.44?
Sievers TOC Analyzers were designed to assure complete oxidation of organics to CO2. This is accomplished with a continuous flow-through UV reactor designed with a UV power output that is many times higher than that required for complete oxidation. The analyzer design was thoroughly validated in the engineering process by testing the overall percent recovery of test compounds in a wide range of concentrations
Which technology offers greater calibration stability: membrane-based conductometric detectors or direct conductometric detectors?
The membrane conductometric technology used by Sievers TOC Analyzer typically results in calibration stability of one year. The membrane technology was designed to eliminate the effects of variations in pH, temperature, membrane fouling, rouging, and dissolved gassses and to assure stable, reliable, and accurate results.
Is there an advantage to a TOC analyzer also being used as a trihalomethane (THM) analyzer?
Each TOC technology responds very differently to different organics. THMs are a class of halogenated compounds that produce a highly exaggerated TOC result with their method.
Can Sievers TOC Analyzers be validated or verified to USP and EP conductivity and water monographs?
Sievers TOC Analyzers, cell constants, and temperature sensors are all easily validated and verified per all USP/EP/JP and cGMP requirements and water monographs. Over the years, GE Analytical Instruments has installed thousands of TOC analyzers that have been fully validated for compendial pharmaceutical water applications.
What is the difference between TOC analyzers and sensors?
TOC analyzers are generally used in critical applications, while TOC sensors, which produce less accurate data, should be used For Information Only (FIO) applications. (For more information on this topic, click here.)