A set of 253 pine nut samples from different geographical regions was obtained from 2020 to 2023 in the frame of the Tracenuts project (PID2020-117701RB-I00). Pine nut samples were analysed under HS-SPME conditions adapted from Vichi et al. (Journal of Chromatography A, 2006, 1125: 117-123. doi.org/10.1016/j.chroma.2006.05.029) using a Combi-pal autosampler (CTC Analytics, Zwingen, Switzerland). An aliquot of approximately 1 g of whole pine nuts was weighed into a 10 mL vial fitted with a PTFE/silicone septum. The sample was conditioned at 70 °C for 10 min, followed by exposing a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber (2 cm length, 50/30 μm film thickness) from Supelco (Bellefonte, Pennsylvania, USA) to the sample headspace for 60 min, at the same temperature. Then, the fiber was desorbed at 260 ˚C for 10 min in the gas chromatograph injection port, the injector was maintained in split-less mode for the first 5 min.

The mono- and sesquiterpene fingerprint was acquired by an Agilent 6890N Network GC system coupled to a quadrupolar mass selective analyser Agilent 5975C Inert MSD (Agilent Technologies, Santa Clara, California, USA). Helium was the carrier gas, at a flow of 1.5 mL/min. Analytes were separated on a Supelcowax-10 capillary column (60 m × 0.25 mm i.d., 0.25 μm film thickness) (Supelco, Bellefonte, Pennsylvania, USA). Column temperature was held at 40 °C for 3 min, increased to 100 °C at 4 °C/min, then, to 200 °C at 5 °C/min and to 260 °C at 15 °C/min, holding the last temperature for 5 min. The temperatures of the ion source and the transfer line were 230 and 280°C, respectively. Mass spectra were recorded at 2.3 scan/s and the electron energy was 70 eV. Data acquisition was performed in the selected ion monitoring (SIM) mode, by registering the Extracted Ion Chromatogram (EIC) of 7 ions which have been reported to be characteristic of the mono and sesquiterpene compounds: m/z 93, 95, 119, 159, 161, 189 and 204.