Please read this excellent article on NB Pentylone and N-ethyl-pentylone detection by The Loop in the UK.
"... with all the valerones being more potent than MDMA, the mis-selling of valerones as ecstasy causes added concern given that an amount that could be considered an ‘average’ dose of MDMA would be a very strong dose of any of these impostors."
"NB Pentylone and N-ethyl-pentylone can also both be detected at home with [Marquis] drug reagent tests as they turn bright yellow instead of purple/black for MDMA."
Pillreports is a global database of Ecstasy" pills based on both subjective user reports and scientific analysis. "Ecstasy" is traditionally the name for MDMA based pills, however here we also include closely related substances such as MDA, MDEA, MBDB. Pills sold as "Ecstasy" often include other, potentially more dangerous, substances such as methamphetamine, ketamine and PMA.