Tagging system
US9156707B2 · kind B2 · utility
1Cited by
16References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 22, 2006 |
| Grant date | Oct 13, 2015 |
| Priority date | — |
| Expiry date | Nov 2, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/13
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of tracing an aqueous liquid, particularly an aqueous urea used for addition to a selective catalytic reduction system to remove NOx from diesel exhaust includes adding a tracer comprising a pre-determined amount of a phenol to the liquid. The 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.