Figure 16.21 A GC chromatogram showing retention times. Carrier gas flow at the column outlet measures 28.1mL/min. The column temperature is 285C. The ambient temperature is 24.8C. Ambient pressure is 760.2mmHg. The column head pressure is 70.4mmHg. The column used was 30 meters in length. EXERCISE 16.2: Calculate the theoretical plate height, H, and the number of theoretical plates, N, for peak 4 in Figure 16.21. You might need to review Section 15.2 to answer this question. It is acceptable to estimate the values of the variables you need for the calculation from the axes of the chromatogram