Determination of serotonin in nuts and nut containing products by liquid chromatography tandem mass spectrometry.

An ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the determination of serotonin in raw and roasted nuts (almond, Brazil nut, cashew, chestnut, coconut, hazelnut, Macadamia nut, pecan, peanut, pine nut, pistachio and walnut) as well as nut products (nut containing snack bars, chocolate and spreads) for the first time. Water extraction without prior defatting was performed to leach serotonin from complex matrices of nuts. Mean recoveries ranged from 64.2 ± 9.6 to 94.7 ± 20.1%. Limit of detection and limit of quantification were between 0.4 and 2.3 and 1.0-7.4 ng/g, respectively. Repeatability and reproducibility values were below 2%. Serotonin content of nuts ranged from 0.05 ± 0.01 (pine nut) to 155 ± 57.0 µg/g (walnut) in raw nuts while it was between 0.03 ± 0.00 (Macadamia nut) and 15.3 ± 1.27 µg/g (pecan) in roasted nuts. Serotonin in nut products was found to range from 0.09 ± 0.00 to 8.99 ± 0.92 µg/g, depending on the nuts they contain.