Reference substances. (A) The ref- erence substances need not be em- ployed in all cases when investigating a new substance. They are provided pri- xxxxxx so that calibration of the meth- od may be performed from time to time and to offer the chance to compare the results when another method is ap- plied.
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.
Reference substances. Wh e r e i n ves- t ig a t i n g a c h e m ic a l s u bs t a n ce, r ef- e r e n ce co m po un ds m a y be u sefu l a n d a n i n ve n t o ry of s u i t a ble r efe r e n ce co m - po un ds n eeds t o be ide n t ified. I n o r de r t o c h ec k t h e a c t ivi t y of t h e i n oc u l u m t h e u se of a r efe r e n ce co m po un d i s de- s i r a ble. A n ili n e, sodi u m ci t r a t e, dex- t r ose, p h t h a lic a cid a n d t r i m elli t ic a cid will ex h ibi t u l t i m a t e biodeg r a d a t io n un de r t h e co n di t io n s of t h i s T es t G u ideli n e m e t h od. T h ese r efe r e n ce s u b- s t a n ces m u s t y ield 60 pe r ce n t of t h eo- r e t ic a l m a xi m u m CO2 a n d s h ow a r e- m ov a l of 70 pe r ce n t DOC wi t h i n 28 d a y s. O t h e r wise t h e t es t i s r eg a r ded a s i n v a lid a n d s h a ll be r epe a t ed u s i n g a n i n oc u l u m f r o m a diffe r e n t so ur ce.
