... Is there a good reason to write in that particular format? There are other easier formats.
textread() was declared obsolete a fair number of years ago; you should probably not be using it for any new code (unless you are using a very old MATLAB release.)
S = fileread('spherical.txt');
parts = regexp(S, ';', 'split');
t = cell2mat(textscan(parts{1}, '%d', 'delimiter', ','));
Q = cell2mat(textscan(parts{2}, '%f', 'delimiter', ','));
Note: your t has 12 entries, but your Q only has 11 entries.
Are you sure you want your t variables to be int32 data type? It is possible, and even quite appropriate for some cases, but if you are not aware that it will be int32 then you can end up with problems in the computation. If you want double instead of int32 then use %f instead of %d. If you want 64 bit integers use %d64
