Gc systems

GC–MS analysis of compounds in the extracts that possessed high antiplasmodial activity was carried out using Agilent Technologies GC systems with a 7000C GC/MS Triple Quad model (Agilent Technologies, Santa Clara, CA, USA) equipped with an HP-5MS column (30 m × 0.25 mm; 0.25 μm). Spectroscopic detection by GC–MS involved an electron ionization system with a high ionization energy of 70 eV, ion source temperature of 250 °C and mass scanning range of 33–600 amu in full scan. Pure helium gas (99.99%) was used as the carrier gas at a constant flow rate of 1 ml/min, and the injector temperature was maintained at a constant of 250 °C. The initial column temperature was set to 60 °C for 2 min and increased to 150 °C with an increasing rate of 10 °C/min. Finally, the temperature was increased to 300 °C at 5 °C/min. One microliter of the sample in ethanol was injected in split mode with a split ratio of 20:1. The identification of the phytochemical compounds in the test samples was performed by comparing their mass spectra with the spectral database of known compounds in the National Institute of Standards and Technology (NIST2011) structural library. Only selected peaks with 80% similarity and above with NIST libraries were chosen and identified.

The Instrument used, Agilent Technologies GC systems with GC-7890A/MS-5975C model
with DB-5MS column (30 m in length × .25 µm in diameter × 250 μm in thickness of
film). The oven temperature was kept at 50°C for 1 minute and the temperature
steadily increased to 25°C/min to 120°C for 5 min and a 1μL sample was
introduced for analysis. Helium gas 99.9% was used as the carrier gas. The flow
rate of carrier gas was 1 mL/minute sample injected temperature was upheld at
230°C and the split ratio was 20 during the experiment. The ionization mass was
done at 70 eV. The mass spectra were recorded for the mass range 55-416 m/z for
26 minutes. The compounds appearing with different peaks were identified by
comparing their mass spectra. During elution through the column they
distinguished based on the production of electronic signals, specific for each
compound appearing in our sample. The mass-to-charge ratio calibration was
compared with each molecule’s mass spectrum (fingerprint). Finally, the mass
spectra obtained for each compound were compared with the PubChem and NIST
libraries.^{23 ,24}