Finding retention time per mass in LC-MS data

Hi all , I need help trying to figure out how to find the retention time in a set of LC-MS data for a particular mass. I've managed to generate the various matrices and plots than can be done though various guides online. However i cant manage to find the command for identifying the time component for a peak. Does anyone know what command or set of commands i could use for this?

Answer 1

[Paolo]

So here is a sample set of data.

I tried using the two functions and even the assist was no help. When I import the data I get two sets of variables. One is a time variable and the second is a set of matrices that correspond to each time variable. with msppresample i can separate the peak into a mass list and intensity matrix that i use, in combination with the original time variable to generate the above diagram.

Edit: Using the intensity matrix from the msppresample i get a series of 1 and 0 for the plot. I need to figure out how to tie this in with the mass and time information though. So are those two commands capable of handling 3d data? and how would it need to be formatted to do so.

Answer 2

[Image Analyst]

Do you want to show us one of the plots? Assuming what I think they look like .... If you have the Signal Processing Toolbox, you can use findpeaks(). If you have the Image Processing Toolbox you can use imregionalmax().