| 摘要 |
<P>PROBLEM TO BE SOLVED: To disclose a method of tracing an aqueous liquid, particularly an aqueous urea used for addition to a selective catalytic reduction system to remove NO<SB POS="POST">x</SB>from diesel exhaust. <P>SOLUTION: This method includes adding a tracer comprising a pre-determined amount of a phenol to aqueous liquid. The aqueous liquid can subsequently be identified by reacting a sample with a reagent containing a predetermined amount of 4-aminoantipyrine in the presence of an initiating compound such that the reaction between the reagent and a phenol in the liquid produces a chromophore and measuring the absorbance of the resulting solution of the chromophore. <P>COPYRIGHT: (C)2013,JPO&INPIT |
