TOC MEASUREMENT OF PHARMA WATERS. Sheesh Gulati. Monitoring Total Organic Carbon in Pharmaceutical High-Purity Water Systems. …How to Meet USP <643> and EP 2.2.44 TOC and USP <645> and EP 2.2.38 Conductivity Requirements. TOC -- HISTORY.
…How to Meet USP <643> and EP 2.2.44 TOC and USP <645> and EP 2.2.38 Conductivity Requirements
Total organic carbon analysis is a determination of organic carbon in a sample regardless of its oxidation state or biodegradability. Other measures of total organic matter (e.g., COD, BOD) may respond differently to solutions of equal carbon concentration depending on the oxygen content or the bidegradation kinetics.
Very similar to a movie with continuous frames, an on- line analyser does not miss a frame or a TOC excursion. However, a laboratory method is like a single frame (still) photograph that takes a "snapshot" of the system. With "snapshots", TOC excursions can be measured wrongly or may be missed completely.
The two basic components of any TOC analyzer are:
1.The Oxidation Reactor, which converts the organic carbon in the water to CO2 gas, either by thermal, chemical or ultraviolet radiation. Oxidation efficiency, assuring complete conversion of the organic carbon to CO2, is critical.
2. The CO2 Detector, which measures the concentration of the CO2 gas generated in the oxidation chamber. This component is critical for precise analytical results, since it directly correlates to the organic carbon content of the analysed water.
The Oxidation Reactor
For ultra-pure water analysis, two
techniques are in common use:
Each of the above mentioned methods has requirements of acids, reagents and gases. This adds to the complexity of measurement and also requires the skill of a trained person, normally a technician or scientist. In most cases the water sample must be removed from the DI plant, this making it susceptible to contamination.
Additional drawbacks of this technique are the routine maintenance required and frequent calibrations to maintain accurate results. With rare exceptions the methods that employ acidification and persulfate addition lose the volatile organics which can be significant contaminants in very low level TOC, high purity water systems. In general, operating costs are high especially as the reagents and gases have a finite shelf-life
Two basic methods are in common use:
Defining the commonly used terms in the <643> method:
USP <643> specifies “periodically” andEP 2.2.44 specifies at “suitable intervals” ??
There are 3 basic requirements that the conductivity equipment must meet:
Model DI 1000
DI 1000 TOC analyzer is a patented product, it can detect total organic carbon (TOC) contained in the water, by calculating it from total inorganic carbon (TIC) and total carbon (TC). DI 1000 analyzer operation principle is to oxidize microorganisms by UV lamp and convert organic carbon into carbon dioxide. Then TOC analyzer adopts direct conductance method to detect the concentration of carbon dioxide and report. During testing procedure, TC and TIC are detected and TOC is equal to TC- TIC (TOC = TC-TIC)