Agilent injector temperature

GC-MS analysis was carried out using an Agilent Technology 6890 gas chromatogram coupled to a 5973 mass spectrometer fitted with a CDS 1500 valve interface held at 250°C. Separation was performed on an SGE BPX5 column (30 m length, 0.25 mm ID, and 25 pm film thickness). Helium at column flow rate of 1.1 mL/min (constant flow rate) was used as the carrier gas. Injection was splitless and injector temperature 250°C. The GC oven temperature was held for 15 min at 30°C and then programmed at 4°C/min to 300°C.The final temperature was held for 9 min. 

The total ion chromatogram of the analysis of a Thai jasmine rice is shown in Fig. 2. The samples was desorbed for 5 minutes on a HP 5973 GC/MS system (Agilent Technologies, Palo Alto, CA). The injector temperature was held constant at 270°C. The GC oven temperature was held for 1 min at 50°C, then ramped to 250°C at 10°C/min. A 30 m, 0.25 mm I.D., DB-5 capillary column with 1.0 p,m film was used with helium as the carrier gas under a constant flow of 40 cm/s. The total GC cycle time consisted of a 30-minute run and a 5-minute cooldown period. Following the first GC/MS run, subsequent samples were prepared ahead so that one sample was run every 45 minutes. The mass spectrometer was operated in scan mode from m/z 50 to m/z 350. 

We use a GC Top 8000 gas chromatograph coupled with a PolarisQ ion-trap mass spectrometer and equipped with an AI3000S autosampler (Thermofinnigan www. thermo.com). The steroids are separated on a DB-1 crosslinked methyl-silicone column, 15 mx 0.25 mm i.d., film thickness 0.25 pm (J W Scientific marketed by Agilent). Helium is used as a carrier gas at a constant pressure of about 35 kPa. A 1-pl aliquot of the final derivatized extract is injected into the system operated in splitless mode (valve opened at 2 min). The GC temperature program is the same described before for the quadrupole GC-MS system. The injector and transfer lines are kept at 260°C and 280°C, respectively. The ion source temperature is 225°C. A damping gas flow of helium is applied to the ion trap. 

The HPLC analysis was performed on an Agilent 1100 series LC (Santa Clara, CA), equipped with a quaternary pump (G1311A) and a UV multiwave length detector (G1365B), set at 220 and 280nm. The injector was a Rheodyne manual injector valve, model 77251 (Santa Clara, CA), equipped with a 20-1 sample loop. The column temperature was controlled using a ThermaSphere TS-130 oven from Phenomenex set at 40 °C. 

Separation of fatty add methyl esters was achieved on an Agilent J W DB-23 fused silica capillary column (60 mxO.251 mm i.d., 0.25 pm Agilent, Santa Clara California, USA). The oven temperature program was initially 120 °C for 5 min, raised to 180 °C at 10 °C min-i, then to 220 °C at 20 °C min-i and finally isothermal at 220 C for 30 min. The injector and detector temperatures were maintained at 220 and 225 °C, respectively. The carrier was high purity helium with a linear flow rate of 1 ml min i and spht ratio 1 50. Fatty add methyl esters were identified using fatty add methyl esters standards (Sigma, St Louis, Mont, USA) by comparison of the retention times of the relative peaks (Nasopwulou et aL, 2011). 

To further characterize the products released upon thermochemolysis, comprehensive GC x GC-TOFMS was utilized. Thermochemolysis was performed at 280°C under conditions as described above. GC x GC-TOFMS analysis was performed using an Agilent 6890 GC with a GC X GC modulator (Leco) coupled to a Pegasus IV TOF mass spectrometer (Leco). The GC injector was operated in split mode (20 1) with a column flow rate of 1 mL/min and held at 250°C. GC x GC separation utilized a nonpolar column and a polar column a BPX5 (30 m X 0.25 mm x 0.25 pm SGE) and a BPX50 (1.8 m X 0.1 mm x 0.1 pm SGE), respectively. The GC oven temperature was held for 10 min at 35°C and ramped to 300°C at a rate of 5°C/min and then held for 5 min the second column was ramped at +15°C relative to the first column with a modulation time was 4 s. Mass spectra were acquired in electron ionization mode from 33 to 500 amu with an acquisition rate of 135 Hz. 

GC-MS was performed on a Hewlett-Packard 6890 GC wifli 7683 autosampler and 5973 mass-selective detector (Agilent Technologies, Palo Alto, CA). Electron impact (El) MS was obtained at 70 eV. A split / splidess injector was used in splitless mode with a purge flow to split at 2.0 min after injection. Chromatograms were run at a constant flow of 0.5 mL /min of He gas. TTie inlet tenq>erature was set at 250 C. An HP-5MS (5% diphenyl-95% dimethylsiloxane) capillary column (30 m x 0.25 mm, 0.25 pm < ) was used with temperature programming from 60 C (1 min hold) to 300 C at 10 C/min witii a al 10 min hold. Solvent samples (1 pL) were injected by the autosampler. SPME sanqrles were manually injected by insertion of the fiber into the mass spectrometer inlet until after the purge flow to split occurred. Mass spectra were recorded from m/z 40 to m/z 550. 

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