[Obi_Juan_Kenobi]

The Marquis reagent is commonly used to test MDMA. It will readily distinguish MDMA from cathinones (aka 'bath salts') which is a common adulterant or substitute. Operations like Dance Safe have popularized this, and the demographic using the deep web seems to be particularly aware of this test and its value.

[Evolved]

Marquis, Mandolin, Mecke and Simon are all sold on DanceSafe and are used to determine only whether a substance contains MDMA (or other similarly desired chemicals) and whether or not it contains PMA and PMMA (undesirable and toxic chemicals). It does not ascertain the quality of such substances nor does it establish concentrations beyond trace amounts. Thank you for your input.