Lab 2 - GC-TCD

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<h1 style = "text-align: left;">Chem 370 | Instrumental Analysis</h1>
<h1 style = "text-align: left; font-weight: bold;">Lab 1: GC-TCD</h1>

**Dr. Al Fischer**   |  Western Carolina University

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# gc-tcd | **chromatography**

Chromatography separates a mixture using a **mobile phase** and **stationary phase**.

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# gc-tcd | **gas chromatography**

Gas chromatography also separates by **boiling point**.

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# gc-tcd | **gas chromatography**

Each peak in the **chromatogram** represents a distinct compounds in the sample.

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# gc-tcd | **gas chromatography**

Retention factor compares R.T. of the sample peak to R.T. of the *system peak*.

$$k\_r = \frac{t\_r - t\_m}{t\_m}$$

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# lab 2 | **Gow-Mac GC-TCD**

**Peak area** is proportional to concentration.

$$C\_n (\%)=\frac{A\_n}{A\_1 + A\_2 + ... A\_n} \times 100\%$$

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# lab 2 | **Gow-Mac GC-TCD**

Peak separation is described the the **resolution**.

$$R\_s = \frac{t\_{r\_2} - t\_{r\_1}}{0.5(W\_{b\_2} + W\_{b\_1})}$$

$$W\_b = 4 \sigma$$
<img src="/assets/images/lab-1/chromatogram.png" style = "height: 250px; margin-left: auto; margin-right: auto; display: block;">

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# gc-tcd | **gas chromatography**

You will use a Gow-Mac gas chromatograph with a **thermal conductivity detector** (GC-TCD)

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# gc-tcd | **gas chromatography**

You will use a Gow-Mac gas chromatograph with a **thermal conductivity detector** (GC-TCD)

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# gc-tcd | **gas chromatography**

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# lab 2 | **Gow-Mac GC-TCD**

**The Experiment:**

1. A blank to check for cleanliness and determine the baseline.
    - Inject 4 uL acetone
    - Want flat line with single peak for acetone
    
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# lab 2 | **Gow-Mac GC-TCD**

**The Experiment:**

1. A blank to check for cleanliness and determine the baseline.
2. 1 unknown sample (obtain from your instructor)
    - Inject 4 uL acetone (instruction in lab manual)
    - Save data as CSV file

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# lab 2 | **Gow-Mac GC-TCD**

1. Determine number of compounds, relative polarities, and percent composition.

1. Determine retention time of each peak.
    1. Calculate area of each peak

1. Attempt to determine likely identity of each compound.
    
    1. Calculate retention factor for each peak and compare to standards
    
1. Calculate resolution for each peak

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# lab 2 | **Gow-Mac GC-TCD**

Determining peak area -- look for video tutorial!  Use `fitPeak()` and `plotPeak()` functions in Julia.

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# lab 2 | **Gow-Mac GC-TCD**

Determining signal-to-noise ratio -- look for video tutorial!

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# lab 2 | **Gow-Mac GC-TCD**

You will need to record the instrument parameters in your notebook today!  Use a Markdown table.

**Table 1: Instrument Parameters**

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# lab 2 | **Gow-Mac GC-TCD**

You will need to record the instrument parameters in your notebook today!  Use a Markdown table.

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class: center

# lab 2 | **Gow-Mac GC-TCD**

You will need to record the instrument parameters in your notebook today!  Use a Markdown table.

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class: center

# lab 2 | **Gow-Mac GC-TCD**

You will need to record the instrument parameters in your notebook today!  Use a Markdown table.

---
class: center

# lab 2 | **Gow-Mac GC-TCD**

You will need to record the instrument parameters in your notebook today!  Use a Markdown table.

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class: center

# lab 2 | **Gow-Mac GC-TCD**

You will need to record the instrument parameters in your notebook today!  Use a Markdown table.

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# lab 2 | **Gow-Mac GC-TCD**

**Next week:**
- Watch/complete the video tutorials on CSV files, data frames, and plots. [ See the [Julia Tutorials](/julia) page ]
- Use the online tutorial for Lab 1 to complete your data analysis.
- No in-person meeting.  I will be watching Piazza during our lab time to answer any questions that come up regarding data processing.
- This lab is due **February 16, 2021**.  Make sure you submit:
    - Your lab notebook .jl file
    - Your lab notebook .html file
    - Your data file(s)