How can I identify peaks in spectra?

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In summary, the conversation discusses the process of identifying peaks in a spectra using various algorithms. Suggestions include using a simple thresholding algorithm, smoothing the data beforehand, or creating a comb filter based on known peak locations. However, determining the correct results and compensating for spectral shifting are important considerations in this process.
  • #1
khdani
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hello,
i've Spectra(set of data points) and i need to identify the peaks of the spectra.
are there any algorithms for that ?
 
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  • #2
Sure, just go through your array collecting points where a[i-1] < a > a[i+1]. Of course, that might give you "peaks" that are just random fluctuations in your data. You could try to prevent that by replacing each a with a weighted average of nearby elements beforehand, smoothing the function.
 
  • #3
it's a very simple algorithm which will give incorrect results...
i've tried more complex algorithms, like looking for slopes from left sides of peak and right sides,
but with no success...
 
  • #4
Well, what are the "correct results" you're looking for?

- Warren
 
  • #5
That's true; now you just need to determine the location of the relevant peaks (whether it be the spectral width of the peak, or using a simple thresholding algorithm--if it's above value X then it's a peak--or running the data through a low-pass filter to smooth out the noise prior to finding the peaks).

Or, if you know a priori where the peaks ought to be, you can use these peak locations to create an appropriate comb filter which filters out only the values at those wavelengths (and of a certain spectral width, once again). But again, you'd need to know exactly what you're looking for, and either compensate for spectral shifting or make the comb sufficiently wide that you don't end up cutting off the peak.
 
Last edited:

1. What are peaks in spectra?

Peaks in spectra refer to the high points or maximum values in a graph of signal intensity versus wavelength or frequency. They represent the specific wavelengths or frequencies where a sample is absorbing or emitting light.

2. Why is it important to identify peaks in spectra?

Identifying peaks in spectra can provide valuable information about the composition and structure of a sample. It can help identify the presence of certain elements or compounds, and can also give insight into the electronic and molecular properties of the sample.

3. What techniques are commonly used to identify peaks in spectra?

The most commonly used techniques for identifying peaks in spectra include UV-Vis spectroscopy, infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance (NMR) spectroscopy. Each technique has its own advantages and is suitable for different types of samples.

4. How do you determine the identity of a peak in a spectrum?

Determining the identity of a peak in a spectrum involves comparing the wavelengths or frequencies of the peaks to known values for different elements or compounds. This can be done using reference databases or by comparing to previously recorded spectra of known substances.

5. Can peaks in spectra be used for quantitative analysis?

Yes, peaks in spectra can be used for quantitative analysis. By measuring the intensity of the peaks and comparing it to a calibration curve or standard solutions, the concentration of a sample can be determined. This is commonly used in various analytical techniques, such as UV-Vis spectroscopy and NMR spectroscopy.

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