Mass spectrometric determination of acromelic acid A from a new poisonous mushroom: Clitocybe amoenolens

As Clitocybe acromelalga, the mushroom Clitocybe amoenolens is responsible for erythermalgia. Acromelic acids isolated from C. acromelalga have been suspected to be to some extend the active principles. The objective was to develop a specific and sensitive liquid chromatographic–mass spectrometric method that would allow acromelic acid A identification and quantification in mushrooms. The method involved a single-step methanol–water extraction followed by a selective cleanup of the extract with solid-phase extraction cartridges (strong-anion exchange). The chromatographic separation was achieved on a porous graphitic carbon column with acetonitrile–water–formic acid as mobile phase. Detection was done with a mass analyzer equipped with a TurboIonSpray® source, operated in the negative ionization mode. Acromelic acid A concentration was determined in dried mushroom at around 325 ng/mg in C. amoenolens and 283 ng/mg in C. acromelalga.