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INVESTIGATION OF RESPONSE DIFFERENCES BETWEEN DIFFERENT TYPES OF TOTAL ORGANIC CARBON (TOC) ANALYTICAL INSTRUMENT SYSTEMS
Citation:
Potter, B B. AND J. C. Wimsatt. INVESTIGATION OF RESPONSE DIFFERENCES BETWEEN DIFFERENT TYPES OF TOTAL ORGANIC CARBON (TOC) ANALYTICAL INSTRUMENT SYSTEMS. Presented at ACS Meeting, Orlando, FL, April 11-15, 2002.
Impact/Purpose:
Establish optimum performance criteria for current TOC technologies for application to Stage 2 D/DBP Rule.
Develop a TOC and SUVA (incorporating DOC and UV254) method to be published in the Stage 2 D/DBP Rule that will meet requirements as stated in the Stage 1 D/DBP Rule (Revise Method 415.3, "Measurement of Total Organic Carbon, Dissolved Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water", to include additional ruggedness data, method study data, and a combustion TOC procedure).
Investigate the cause for instrument response differences as observed between different kinds of TOC instrument systems.
Develop a method procedure that will control and/or eliminate the cause of TOC instrument response differences.
Revise Method 415.3 Quality Control section to include additional controls for the minimization and/or the elimination of instrument response differences.
Publish Method 415.3 and document in a journal article the development of the method.
Description:
Total organic carbon (TOC) and dissolved organic carbon (DOC) have long been used to estimate the amount of natural organic matter (NOM) found in raw and finished drinking water. In recent years, computer automation and improved instrumental analysis technologies have created a variety of TOC instrument systems. However, the amount of organic carbon (OC) measured in a sample has been found to depend upon the way a specific TOC instrument treats the sample and the way the OC is calculated and reported. Specifically, relative instrument response differences for TOC/DOC, ranging between 15 to 62%, were documented when five different source waters were each analyzed by five different TOC instrument systems operated according to the manufacturer's specifications. Problems and possible solutions for minimizing these differences are discussed.