U-47700 is a novel synthetic opioid, one of a very small number of non-fentanyl-derived opioids on the market. Testing with the marquis and froehde reagents both gave fizzing with no colour change on a sample of U-47700. You can see the rather uninteresting images below:
Note that the marquis reagent is off-clear but this does not represent a change from its starting colour.
