Common use of Reference substances Clause in Contracts

Reference substances. Where inves- tigating a chemical substance, ref- erence compounds may be useful and an inventory of suitable reference com- pounds needs to be identified. In order to check the activity of the inoculum the use of a reference compound is de- sirable. Aniline, sodium citrate, dex- trose, phthalic acid and trimellitic acid will exhibit ultimate biodegradation under the conditions of this Test Guideline method. These reference sub- stances must yield 60 percent of theo- retical maximum CO2 and show a re- moval of 70 percent DOC within 28 days. Otherwise the test is regarded as invalid and shall be repeated using an inoculum from a different source.