Agilent 7683 series auto sampler

The extraction and derivatization protocol for urinary organic acids was optimized based on a previously reported method (17 (link)). Derivatized extracts (e.g., organic acids) were injected by an Agilent 7683 Series autosampler (Agilent Technologies, Palo Alto, CA, USA) followed by the analysis employing Agilent 6890N GC system coupled with electron impact (EI) ionization mode 5973N mass selective detector (Agilent Technologies, Palo Alto, CA, USA). Raw GC-MS data (“.D” file format) were first transformed into CDF format by the ChemStation Data Analysis software (Agilent Technologies, Palo Alto, CA, USA) prior to data pretreatment. Identification and quantification of metabolites was firstly processed and analyzed automatically by a web-based software called GC-AutoFit (http://gcms.wishartlab.com/) and results were further confirmed manually following the method as previously described (18 (link)). Further details on the organic acid extraction, derivatization, separation, and GC-MS data processing of urine samples were elaborated previously (19 (link)).

GC-MS analysis was carried out on an Agilent 6890 Gas Chromatograph coupled with a Quadrupole Mass Spectrometer (MS) (Agilent, Germany), equipped with an Agilent 7683 series auto sampler (Agilent, Germany). A Hewlett Packard 5973 Mass Selective Detector (MSD) was used for GC-MS analysis. The GC was fitted with a 30 m DB-5MS (5% phenyl methyl siloxane) Agilent column, with a 0.25 mm internal diameter and a film thickness of 0.25 μm. The samples were injected in splitless mode at 300 °C. Helium was used as the carrier gas, with a flow rate of 1 mL min⁻¹. The oven was programmed at 50 °C for 2 minutes, then ramped at 10 °C per minute to 325 °C and held for 15 minutes. The MS was operated in Electron Impact mode (EI; 70 eV), at a full scan range of m/z 50 to 550, with a scan time of 3s per scan. Data acquisition was carried out using Data Analysis Version 3.3 (Bruker Daltonics) data system. Data analysis was performed using MSD ChemStation Version D.00.01.

Pyrethrins were analyzed by Agilent 6890N Network GC system equipped with an Agilent 7683 series auto sampler, mass selective detector (MSD) model 5975B network, and a HP-5MS analytical column (30 m × 0.25 mm × 0.25 μm film thickness) (Agilent Technologies, Santa Clara, CA, USA). Two μL of sample were injected in splitless mode, and the injector was held at 260 °C, the carrier gas helium (99.999%) at a constant flow rate of 1.2 mL/min. The oven temperature was initially held at 100 °C for 1 min, ramped to 270 °C at 10 °C/min and held for 1 min, ramped to 280 °C at 1 °C/min and kept for 1 min. The temperatures of ion source, quadrupole, and transfer line were set as 230 °C, 150 °C, and 280 °C. The solvent delay was 10 min. Ionization was performed using electron impact (EI) mode at 70 eV, and mass spectrometer was used in selected ion monitoring (SIM) mode. The total running time was 30 min. Table 2 summarizes the ions monitored along with the relative abundances and the typical retention time. The chromatograph is shown in Figure 2.