Qualitative Analysis Of Gas Chromatography

Volatile and thermally stable organic compound can be analyzed qualitatively and quantitatively using gas chromatography. The qualitative analysis obtained from the retention time, tR of the component while the quantitative analysis obtained from the peak area of chromatogram (Christian, 2004). The retention time refers to the time between the sample introduction and the elution from the column. The peak area of chromatogram shows the elution time at the x-axis and size of the detector signal at the y-axis (Lundanes, Reubsaet, & Greibrokk, 2014). In this experiment, the sample used as a volatile and thermally stable organic compound are methanol, n-butanol, standard mixture of methanol and n-butanol, and unknown sample. Only the retention time

The mobile phase used must be an inert gas and unreacted with neither the stationary phase nor the sample components. Besides that, the gas used also must be of high purity and can be purified if necessary to remove traces of oxygen, water, and hydrocarbons (Lundanes, Reubsaet, & Greibrokk, 2014). This is why the nitrogen gas, hydrogen gas and CDA gas used as a carrier gas that acts as the mobile phase in this experiment. The split injection mode was used in this experiment using autosampler as injection system due to the smaller volume of sample, which is 0.1 L that automatically injected into a glass-lined heated injection port (Mendham, Denney, Barnes, & Thomas, 2000). A capillary column is used due to its advantageous compared to a packed column. In addition, the gas-liquid chromatography used in this experiment limiting the types of the capillary column used either porous-layer open tubular (PLOT) or support-coated open tubular (SCOT) column (Lundanes, Reubsaet, & Greibrokk, 2014). There are several different types of detector used in gas chromatography such as flame ionization detector (FID), which is used in this experiment as it efficiently detects hydrocarbon or organic compound. The FID also knew as a universal detector of organic compounds besides having high sensitivity, stability, fast response and wide linear response range that is 107. This is due to the fact that gas chromatography only suitable to be used for a sample that able to exist in the gas phase thus only applied to volatile materials while including substances that have an appreciable vapor pressure at temperatures up to 400C (Mendham, Denney, Barnes, & Thomas, 2000). Furthermore, the organic compound such as methanol and n-butanol were used as the sample in this experiment. Lastly, a computer that has been installed with a chromatogram software is used in the laboratory as a display system where the