Tq8040 ms

Essential oil samples were prepared by the extraction of 10 µL of crude N. cataria essential oil with 1.5 ml of MTBE, which was then dried with Na₂SO₄ and centrifuged at 13 Krpm. The supernatant was transferred to a sampling vial for analysis. Essential oil separation was performed on a Shimadzu 2010 Plus gas chromatograph equipped with an AOC-6000 auto-sampler. The analysis of the relative abundance of compound fragments was performed on a Shimadzu TQ8040 MS.
An injection volume of 1 µL was separated using chromatographic grade helium on a H-Rxi-5Sil MS column held at 35 °C for 4 min then heated to 250 °C at 20 °C/min then held for 1.25 min at 250 °C. The inlet temperature was 250 °C with a splitless injection. The ion source temperature was set at 200 °C, the interface temperature was set at 250 °C, the solvent cut time was 3.5 min, and the detector voltage was set to 0.2 kV with a threshold of 1000. Peak integration percentages were generated using the GCMSsolution v4.3© software from Shimadzu Corporation. Individual identities were determined by comparing the mass spectral results to current literature and screening them in the NIST05.LIB, NIST05s.LIB, W10N14.lib and the W10N14R.lib mass spectral libraries.

Three mobile GC–MS devices were evaluated and compared to a state-of-the-art benchtop stationary GC–MS, labeled here as Stationary (TD-20 thermodesorber with GC 2010 plus TQ8040 MS, Shimadzu, Kyoto, Japan). The following models were used: (i) the E2M with a TD unit (Bruker Daltonics GmbH, Leipzig, Germany), MobE; (ii) the Hapsite ER with a TD unit (INFICON Holding AG, Switzerland), MobH; and (iii) the Torion T-9 with an SPME inlet (PerkinElmer, USA), MobT. The optimized instrumental parameters for the comparison among the devices are described in detail in the electronic supplementary material (Supp. S.1).
Prior method optimization was required due to the specific differences in the instrumental configuration of each device including the introduction of the samples. In general, two introduction devices, TD and SPME, were employed to test their suitability for analysis of complex mixtures of VOCs in mobile GC–MS systems. TD was selected since it ensures a known amount of sample to be introduced to the analysis in comparison to probe sampling. The sampling was based on the adsorption to a similar sorbent material across the instruments and subsequent desorption by high temperature. For MobT, however, TD was not available and SPME was used instead.