Find Maximum of Graph in Excel - Any Help Appreciated!

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Discussion Overview

The discussion revolves around finding the maximum point of a graph plotted in Excel, specifically in the context of analyzing cyclic voltammograms. Participants explore various methods to identify the peak coordinates of the graph.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant inquires about methods to find the maximum of a graph in Excel, expressing uncertainty about whether estimation is necessary.
  • Another participant asks if the data is arranged in columns, seeking clarification on the data structure.
  • A participant confirms that the data consists of two columns: potential and current.
  • One suggestion involves using the "Sort" function in Excel to identify maxima based on the arrangement of data.
  • A participant notes that the graph represents a cyclic voltammogram and mentions the importance of finding the peak cathodic current (Ipc) at the turning point of the potential scan.
  • Another participant suggests using the Excel MAX() function to find the maximum value, while also mentioning the potential need for custom interpolation methods to identify inflection points.
  • A later reply references an external resource, indicating that the maximum value corresponds to Ipc and suggests that the scan may not have reached a high enough potential to observe the peak.

Areas of Agreement / Disagreement

Participants present multiple methods for finding the maximum, but there is no consensus on the best approach or whether additional steps, such as interpolation, are necessary. The discussion remains unresolved regarding the optimal method to identify the peak in the context of cyclic voltammetry.

Contextual Notes

Participants express varying levels of familiarity with Excel functions and the specific requirements of analyzing cyclic voltammograms, which may affect the applicability of suggested methods.

higherme
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Does anyone know how to find the maximum of a graph using excel?

so i have this graph i plotted out, and i want to find the coordinates of the peak, is there a way to do it? or do i just have to estimate?

any help would be appreciated! thanks!
 
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Are you graphing from data arranged in columns?
 
yes... i have two columns

one column is the potential and the other one is the current
 
Highlight the column in question. Go to the pulldown menu "Data" and choose "Sort". The maxima will be the first (or last) value after sorting depending on whether you choose ascending or descending order.
 
hm..sorry i forgot to tell that this is a cyclic voltammogram

ya... that will work and it will give me the highest point, which is at the turning point for the potential scan (from cathode reaction to anode reaction). I want to find the peak cathodic current Ipc
 
The excel MAX() function will also do that kind of thing. If you need to interpolate somehow or find an inflection point I don't think there are predefined functions. You can write your own.
 
Look at http://www.chem.uic.edu/chem421/cv.PDF web site. You will notice that the maximum value is the Ipc. If that point is the turning point on your scan, you didn't scan to a high enough potential to see the peak. You still have to interpolate the baseline.
 

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