How to filter low frequency data set?

I have attached my example data set. What i would like to do is correct the data in each row based on the maximum value of the row. Meaning i need to first find the max value in each row, did this with a loop, and then subtract the max of the from the entire row, this will shift the high data to zero and the low number will become (-) values. I want to do this for each row in order to normalize the data and get rid of waviness from row to row.

Here's what i've got so far, i'm not expert it's probably obvious. The variable imax is the max values from each row, i'd like to iteratively subtract this number from each row of the same index. Stuck on that.

A = zg3
a = size(A,1)
imax = cell(a);
for a = 1:size(A,1)
  zgmax = max(A(a,:))
  imax{a} = zgmax;
end