friday september 26th

Course Logistics and Announcements

• Wednesday's Class: Dedicated to students for working on lab reports or paper outlines. Students should utilize the time effectively.
• Paper Outline Due Date: Monday, the $6^{th}$.
• Lab Report Due Date: Also Monday, the $6^{th}$. There was an unusual convergence of deadlines.
• Quiz Day: Friday of the current week.
• Poster Due Date: One week after the quiz, on the $10^{th}$, to Ashley and the instructor. Partners should have started working on their posters.
• Attendance: Instructor inquired if anyone had informed classmates about being late or absent.

Efficiency ($N$) and Accuracy of Gaussian Peaks

• Efficiency Symbol: Represented by the capital letter $N$.
• Equation Derivation: The equation for efficiency was derived by "Big Joe Fowler," with Dorsey, the instructor's PI, signing off on it.
• Gaussian Peak Inaccuracy: Gaussian peaks can be highly inaccurate, specifically by about $40\%$.
• Improved Accuracy: The accuracy is typically $\pm 1.5\%$ when the asymmetry ratio ($b/a$) is anywhere from $1$ to $2.76$. This range indicates a fairly accurate measurement.

Peak Asymmetry: Tailing vs. Fronting

• Asymmetry Ratio: If $b/a \approx 1$, the peak is fairly Gaussian (symmetrical).
• Tailing Peak: A peak that starts strong but does not return to baseline quickly; the area after the peak maximum (segment $b$) is greater than the area before it (segment $a$). This is represented by a $b/a > 1$.
• Fronting Peak: A peak where the area before the peak maximum (segment $a$) is greater than the area after it (segment $b$). In a fronting peak, segment $b$ is smaller than segment $a$, meaning $b/a < 1$.
• Handling Fronting Peaks: In cases of fronting, the asymmetry ratio might be inverted (e.g., $a/b$) to maintain a value of $1$ as the lowest or reference point, generally referring to asymmetry.

Height Equivalent to a Theoretical Plate (HETP or $h$)

• Definition: HETP (or $h$) is another measure of column performance, closely tied to efficiency ($N$).
• Acronym Meaning: HETP stands for Height Equivalent to a Theoretical Plate.
• Formula: $h = \frac{L}{N}$
  • $L$: Length of the column.
  • $N$: Efficiency (number of theoretical plates).
• Units of $h$: The units for $N$ are unit