EXP 5 CHM260.docx - CHM 260 LABORATORY REPORT Experiment Number 5 Title Gas Chromatography(GC Date of Report Submission 15th December 2017 Group members

EXP 5 CHM260.docx - CHM 260 LABORATORY REPORT Experiment...

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CHM 260 LABORATORY REPORT Experiment Number: 5 Title: Gas Chromatography (GC) Date of Report Submission: 15th December 2017 Group members: NAMES STUDENT ID MUHAMMAD NAZIRUL NAZMI BIN MOHD RAZALI 2017265618 FATIN NUR IZZATI BINTI MD SHUKOR 2017412304 SITI AISHAH BINTI AZMAN 2017644796 ZUNNURAINI ADAWIYAH BINTI ZULKAFLI 2017462602 Lecturer’s Name: Madam Noor Faezah Binti Mohd Sani EXPERIMENT 5: Gas Chromatography (GC)
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OBJECTIVES 1. To determine the retention times t R of n-butanol and 2-propanol. 2. To identify the components present in a standard mixture based on the t R . 3. To identify the components present in an unknown sample. 4. To determine the effect of temperature on t R and R s . INTRODUCTION Gas chromatography is an analytical separation technique that analyses compounds eluted from the column, which carried through the column by a gas mobile phase. The carrier gas in our experiment was nitrogen. We used nitrogen because it is inexpensive but gives reduces sensitivity. A detector was located at the end of the column in gas chromatography to measure the solutes that elute from it. In order to obtain an ideal chromatogram, there are many parameters that need to be adjusted. Ideal parameters give chromatograms with the high resolution in the short amounts of time. There are many parameters that can affect both the elution time and the resolution but for this experiment, we focused on effects of temperature and pressure. In gas chromatography, an increase in temperature is only favoured up to a certain point. The increase temperature reduces the time of elution for all the analytes, but after a certain point, it causes a decrease in the resolution. Pressure also needs to be controlled in order to obtain a favourable chromatogram. High pressure causes backflow which causes elution time to increase. Since the temperature and pressure are dependent on each other and it would take too long to figure out mathematically, the parameters were optimized in our experiment with the Simplex Optimization software. The Simplex Optimization software can only be used if the parameters being optimized are dependent on each other. This software used data from test runs to calculate what it thought to be a good set of parameters. The results from those parameters were then re-entered into the system to make a better measurement. In our experiment, we performed as many trials as possible in the time allotted. In the end, we used the parameters that gave a chromatogram that looked to have the highest resolution in the shortest amount of time.
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