Gc ms tq8030 spectrometer

GC–MS analysis of all samples were carried out on a Shimadzu GC–MS TQ8030 spectrometer equipped with a split/splitless injector and SH RTX-5MS (30 m × 0.25 mm, 0.25 µm film) fused silica capillary column. Carrier gas was helium (99.999%) at a flow rate of 1 mL/min. An aliquot of 1 µL was injected in splitless mode, with injector temperature set at 270 °C. The temperature program was as follows: 50 °C for 1 min, increased to 280 °C at 10 °C min⁻¹ and increased to 300 °C at 5 °C min⁻¹. The ion source and transfer line temperatures were 200 °C and 290 °C respectively. The ionization method was electron impact at a voltage of 70 eV. Spectra were obtained over a mass range of m/z 45–650. For the identification of compounds, mass fragmentation patterns were compared with NIST library (NIST17-1, NIST17-2, NIST17s) and Kovats retention indices were compared with literature values. The identities of the compounds were confirmed by comparing retention index and fragmentation patterns of each compound with authentic standards.

For the spike-recovery study, 3 O,O-dimethyl OPs (parathion-methyl, fenitrothion and azinphos-methyl) were spiked to OPs-free samples with known amounts (each sample contained one pesticide). Then, the samples were thoroughly mixed and incubated for 1 h before extraction and purification by QuEChERS. The residues were analyzed by the optimum dcELISAs, and the OP concentration was calculated using the calibration curves.
The correlation study of dcELISAs and GC–MS/MS was performed as follows. Cucumber samples spiked with OPs (25, 50 and 100 ng/g) were analyzed by dcELISAs and GC–MS/MS. The GC–MS/MS analysis of O,O-dimethyl OPs (parathion-methyl, fenitrothion and azinphos-methyl) in the spiked cucumber samples was developed using a Shimadzu GC/MS-TQ8030 spectrometer (Scan/MRM mode). The calibration curves were evaluated with matrix-matched standard calibrations in blank extracts of cucumber (five concentrations including 20, 50, 100, 200, and 400 ng/mL were used). The GC separation was performed on an Rtx-5 MS column (30 m × 0.25 mm × 0.25 μm film thickness). The Electron ionization mode at an ionizing energy of 70 eV was used with the ion source at 230 °C. The OPs concentrations in the spiked cucumber samples were determined and the linear regression equations between ELISAs and GC–MS/MS were calculated.