A SIMPLE, MULTIPLE SIMULTANEOUS SPECTROPHOTOMETRIC METHOD FOR BOD DETERMINATION USING DCIP AS THE REDOX COLOR INDICATOR

ABSTRACT

Especially in the analysis of environmental samples, it is necessary to perform rapid, simple and multiple analyses because it highly desirable to determine the results quickly as well as to analyze numerous samples simultaneously. We use 2,6-dichlorophenolindophenol (DCIP) as a redox color indicator for the Biochemical Oxygen Demand (BOD) determination in this report. The absorbance of DCIP decreases due to the metabolism of organic substances in aqueous samples by Pseudomonas fluoresens biovar V. Our technique using a microplate reader is able to measure 96 samples simultaneously. Thus real samples, blanks, standards and replicates can be determined concurrently, ensuring the accuracy of this method. The process requires approximately 20 min per determination, compared with 5 days for the standard BOD method. This method gives a linear response (r ² = 0.943) to OECD synthetic sewage samples from 50 to 430 mg L ⁻¹.

Keywords:

• Biochemical Oxygen Demand
• 2,6-dichlorophenolindophenol
• Pseudomonas fluoresens
• Spectrophotometry
• Microplate reader

ACKNOWLEDGMENTS

The authors gratefully acknowledge the financial support for this work from the International Center for Environmental Technology Transfer (ICETT). In addition, we wish to thank Mr. K. Amasaki (Meitec Co.) and Mr. A. Yoshida (Akebono Research and Development Center, Ltd.) for technical assistance.