To calculate the efficiency (number of plates) and plate height for the given components, we use the following formulas:

1. Number of Plates ($N$):

$N = 16 \times \left(\frac{t_R}{W_b}\right)^2$ where:

• $t_R$ = retention time of the compound (elution time)
• $W_b$ = peak width at base

2. Plate Height ($H$):

$H = \frac{L}{N}$ where:

• $L$ = length of the column (in mm, so convert 25 cm to 250 mm)
• $N$ = number of plates

Data for the column:

• Length of column, $L = 250 \, \text{mm}$
• Flow rate = 1.2 mL/min (not directly needed for these calculations)

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Component 1:

• $t_R = 120 \, \text{s}$
• $W_b = 28 \, \text{s}$

1. Calculate $N$: $N = 16 \times \left(\frac{120}{28}\right)^2$ $N = 16 \times \left(4.2857\right)^2 = 16 \times 18.3673 = 293.88$

2. Calculate $H$: $H = \frac{250}{293.88} = 0.851 \, \text{mm}$

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Component 2:

• $t_R = 255 \, \text{s}$
• $W_b = 70 \, \text{s}$

1. Calculate $N$: $N = 16 \times \left(\frac{255}{70}\right)^2$ $N = 16 \times \left(3.6429\right)^2 = 16 \times 13.2657 = 212.25$

2. Calculate $H$: $H = \frac{250}{212.25} = 1.178 \, \text{mm}$

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Component 4:

• $t_R = 608 \, \text{s}$
• $W_b = 98 \, \text{s}$

1. Calculate $N$: $N = 16 \times \left(\frac{608}{98}\right)^2$ $N = 16 \times \left(6.2041\right)^2 = 16 \times 38.4773 = 615.64$

2. Calculate $H$: $H = \frac{250}{615.64} = 0.406 \, \text{mm}$

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Final Results:

1. Component 1:

   • $N = 293.88$
   • $H = 0.851 \, \text{mm}$

2. Component 2:

   • $N = 212.25$
   • $H = 1.178 \, \text{mm}$

3. Component 4:

   • $H = 0.406 \, \text{mm}$

Would you like me to calculate similar metrics for the other components or explain the steps further? 😊

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Expansion Questions:

1. How do variations in column length affect the plate height?
2. Why is the plate height important for chromatography performance?
3. How does flow rate impact retention times and peak widths?
4. What role does the stationary phase (C-18) play in separation?
5. Can this calculation method be applied to gas chromatography?

Tip:

Peak symmetry can also provide insights into column performance; consider calculating the asymmetry factor if peaks are not Gaussian.