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Improving Colorimeter Performance on a Continuous Hexavalent Chromium Analyzer

IP.com Disclosure Number: IPCOM000083723D
Original Publication Date: 1975-Jul-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Lozier, RG: AUTHOR

Abstract

Hexavalent chromium (Cr+6) is a toxic pollutant which may be present in wastewater. Analysis is normally a laboratory procedure described in "Standard Methods for the Examination of Water and Wastewater", Published by American Public Health Association, American Water Works Association and The Water Pollution Control Federation, 1971 Edition. The method is colorimetric utilizing s-diphenylcarbazide reagent (DPC). DPC reacts with Cr+6 to produce a reddish purple color which is measured spectrographically at 540 mu.

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Improving Colorimeter Performance on a Continuous Hexavalent Chromium Analyzer

Hexavalent chromium (Cr+6) is a toxic pollutant which may be present in wastewater. Analysis is normally a laboratory procedure described in "Standard Methods for the Examination of Water and Wastewater", Published by American Public Health Association, American Water Works Association and The Water Pollution Control Federation, 1971 Edition. The method is colorimetric utilizing s- diphenylcarbazide reagent (DPC). DPC reacts with Cr+6 to produce a reddish purple color which is measured spectrographically at 540 mu.

Recently, continuous monitoring instrumentation for wastewater has become available. Since hexavalent chromium analysis is relatively easy to perform, monitors for this parameter are popular. Ideally, an instrument of this nature should provide continuous data accurately with minimum attention to maintenance and calibration. Monitor Performance.

Referring to Fig. 1, the basic components are identified for one such Cr+6 analyzer which was evaluated. The metering pumps provide accurate delivery of the sample and reagent. The A pump also provides a means of removing air bubbles which cause interference during measurement. The mixing coil serves as a reaction vessel for color development. The colorimeter performs the actual detection and measurement.

The particular analyzer employed utilized a dual-beam colorimeter. In this analyzer the sample stream is divided to achieve a reference stream. The reference stream does not mix with the reagent and serves to eliminate any interference from color that may...