Saturn 2000 ion trap gc ms

We collected (commonly discoloured) droplets of honeydew from plants heavily infested with pea aphids, using a 10-µL glass capillary fitted with a rubber bulb. We collected a total of 50 µL of honeydew and expelled it into a 4-mL glass vial with a rubber septum lid. Through this lid, we inserted a carboxen-polydimethylsiloxene-coated solid-phase micro extraction (SPME) fibre (75 µm; Supelco Inc., Bellefonte, PA, USA), allowing absorption of honeydew odorants on this fibre for 24 h at room temperature. Prior to each odorant collection, we conditioned the fibre at 280 °C for 5 min in a gas chromatograph (GC) injection port. We desorbed odorants from the fibre in the hot (250 °C) injection port of the GC, and analyzed odorants by GC-mass spectrometry (MS) using a Saturn 2000 Ion Trap GC-MS fitted with a DB-5 GC-MS column (30 m × 0.25 mm i.d.; Agilent Technologies Inc., Santa Clara, CA, USA) in full-scan electron impact mode. We used a flow of helium (35 cm s⁻¹) as the carrier gas with the following temperature program: 40 °C (5 min), 10 °C min⁻¹ to 280 °C (held for 10 min). We identified volatiles by comparing their retention indices (RI) relative to n-alkane standards [47 (link)] and their mass spectra with those reported in the literature [48 ] and with those of authentic standards.

After adding octyl acetate as an internal standard to HSV extract, we analyzed 2-µl aliquots by gas chromatography-mass spectrometry (GC-MS), operating a Saturn 2000 Ion Trap GC-MS fitted with a DB-5 GC-MS column (30 m × 0.25 mm i.d.; Agilent Technologies Inc., Santa Clara, CA 95051, USA) in full-scan electron impact mode. We used a flow of helium (35 cm s⁻¹) as the carrier gas with the following temperature program: 50 °C (5 min), 10 °C min⁻¹ to 280 °C (held for 10 min). The temperature of both the injector port and ion trap was 250 °C. To reveal the presence of low-molecular-weight carboxylic acids (which chromatograph poorly), we converted carboxylic acids to the corresponding silylated derivatives (which chromatograph well). To this end, we treated a 100-µL aliquot of HSV extract with BSTFA (10 µl; N,O-bis(trimethylsilyl)trifluoroacetamide) and TMCS (10%; trimethylchlorosilane; both Pierce Chemical Co., Rockford, IL 61101, USA) and after 5 min without any work-up analyzed 2-µl aliquots by GC-MS. We identified odorants in HSV extract by comparing their retention indices (RI; relative to n-alkane standards^{65 (link)}) and their mass spectra with those reported in the literature⁶⁶ and with those of authentic standards (Table 1).