Agilent 1100 series lc ms

All reactions were monitored by thin-layer chromatography (Huanghai, Yantai, China). A part of each compound was visualized by UV light (Yukang, Shanghai, China). NMR spectra were recorded on a Bruker Avance II 600 spectrometer at 600 MHz for ¹H-NMR and 150 MHz for ¹³C-NMR with TMS as the internal standard. Chemical shifts are expressed in δ (ppm). The HPLC-MS were recorded on Agilent 1100 series LC/MS. Column chromatography was carried out using silica gel (300–400 mesh, Huanghai, Yantai, China). Silica gel chromatography solvents were of analytical grade (Huanghai, Yantai, China). All reaction solvents were dried prior to use according to standard procedures (Taitan, Shanghai, China).

Approximately 12 grams of the different catnip essential oils were repeatedly chromatographed on a silica gel column using a stepwise gradient of hexane-EtOAc from 100%:0% to 80%:20%. CR9 crude essential oil was used for Z, E-nepetalactone purification and CR3 crude essential oil was used for E, Z-nepetalactone purification. Achieved fractions containing the target components were monitored by silica H TLC (hexane-EtOAc/90%:10%) and LC–MS obtaining Z, E-nepetalactone (800 mg) and E, Z-nepetalactone (200 mg). For LC-MS analysis, a Hewlett Packard Agilent 1100 Series LC/MS (Agilent Technologies, Waldbronn, Germany) equipped with an autosampler, quaternary pump system, DAD, degasser, MSD trap with an electrospray ion source, and software for data processing (HP ChemStation) was applied. The structures of these two purified compounds were determined and verified by UV, MS and NMR spectrometric methods, the latter using a Bruker NMR 400 MHz, and in comparison with references^{59 (link)}.

For LC-DAD-MS analysis, a Hewlett Packard Agilent 1100 Series LC/MS (Agilent Technologies, Waldbronn, Germany) equipped with autosampler, quaternary pump system, DAD detector, degasser, MSD trap with an electrospray ion (ESI) source was employed. Data acquisition and processing was achieved using HP ChemStation, Bruker Daltonics and DataAnalysis software (Agilent, ver 4.1). Chromatographic separation was performed on a Polaris amide-C18 column, 250 × 4.6 mm, 5um (Varian Inc.) with a binary mobile phase containing solvent A (0.1% FA in water) and B (0.1% FA in ACN). Elution gradient started at 10% B and linearly increased to 20% in 20 min; during 20–30 min, linearly increase to 30% B; during 30–40 min, isocratic elution at 30% B with a flow rate of 1.0 mL/min. The UV detector was set to monitor at 254 (for hippuric acid), 280 (for phenolic acid & flavanols), 370 (for flavonols), and 520 (for anthocyanidins) nm. Mass spectral data acquisition was achieved under positive polarity (ESI+) with a needle voltage at 3.5 kV and scanned from m/z 100 to 1200. Nitrogen was used as dry gas at a flow rate of 12 L/min and capillary temperature was at 350 °C. Nitrogen was used as nebulizer gas at 60 psi, and helium as collision gas.