Ms grade

All excised and digested bands were analyzed by LC⿿MS/MS. Peptides were chromatographically separated using the EASY-nLC II system (Thermo, Germany) with a 2 column set up: trap column C18-A1, 2 cm (Thermo, Germany) and analytical column PepMap C18, 15 cm ÿ 75 μm, 3 μm particles, 100 ÿ pore size (Thermo, Germany). Mobile phases used were A: 0.1% formic acid in water and B: 0.1% formic acid in acetonitrile. All solvents used were MS grade (Sigma, Germany). Total of 2 μL of each sample was loaded and separated by a gradient over the course of 80 min with a flow rate of 300 nL/min. The flow gradient was (i) 0⿿5 min at 5% B, (ii) 5⿿55 min, 5⿿70% B, (iii) 55⿿60 min 70⿿95% B, (iv) 60⿿70 min 95% B, (v) 70⿿75 min 95⿿5% B, (vi) 75⿿80 min 5% B.
Peptides were analyzed by LTQ Orbitrap XL mass spectrometer in data dependent mode with nano-ESI spray voltage of 1.9 kV, capillary temperature of 275 °C and tube lens value set at 110 V. All spectra were acquired in positive mode with high-resolution full scan in the mass range m/z 300⿿2000 and Orbitrap resolution of 30,000. The 5 most intense precursors were subjected to collision induced dissociation (CID) with normalized collision energy of 35 and activation time of 30 ms. Dynamic exclusion with 1 repeat count over 10 s and exclusion for 10 s was applied.

In this
study 18 OH-PCB standards were used
(Table S1): 4′-OH-CB35, 4′-OH-CB79,
4,4′-diOH-CB80, 4′-OH-CB127, 4,4′-diOH-CB111,
4-OH-CB130, 4-OH-CB193, 4′-OH-CB30, 2-OH-CB77, 4-OH-CB107,
4,4′-diOH-CB83, 4′-OH-CB159, 4-OH-CB172, 4′-OH-CB120,
4,3′-diOH-CB90, 4-OH-CB108, 4,2′-diOH-CB107 and 4,3′-diOH-CB107.
All OH-PCB standards were synthesized at Stockholm University, Department
of Environmental Chemistry (current Department of Environmental Science),
as described by Bergman et al.^{24 (link)}For flow injection analysis, the water phase used was prepared from
ultra high purity water (Riedel de Haën, HPLC grade, Germany)
and ammonium bicarbonate (Sigma-Aldrich, MS grade, Germany). The pH
of the buffer was adjusted to 8.0 with ammonia (Merck, 25%, MS grade,
Canada). Acetonitrile (Rathburn, S-grade, Scottland) was used as the
organic component of the mobile phase.
Theophylline, polyalanine
4–7, sulfaguanidine, sulfadimethoxine,
and val-tyr-val all in Major Mix IMS/ToF Calibration Kit (Waters Corporation,
U.K.) as well as lauric acid, linolenic acid, cholate (kindly donated
by Miklós Mohai from the Stockholm University and Jaanus Liigand
from the University of Tartu) were analyzed together with the OH-PCBs
for calibration of the cyclic IMS measurements (CCS values vs drift
time).

As the aim of this study was to rapidly assess the lavender oils received by essential oil distributors for the purpose to characterize and grade oils of varying quality, a distributor provided 54 lavender oil samples for characterization. Of these, 30 originated from France/Bulgaria and 24 originated from Indonesia/Cambodia. Nine additional oils of unknown origin (unclassified samples) were also provided for analysis.
Each sample was prepared by diluting 20 µL into 2.0 mL hexane (MS Grade, Sigma Aldrich, Castle Hill, NSW, Australia). A 50 ppm C₈-C₂₂ mixed alkane standard (Fluka, Castle Hill, NSW, Australia) was used as an internal standard. Each sample was analyzed in in triplicate and reported as the average response.