Peak filter - trouble using a peak filter to amplify my peak

I am trying to use a peak filter to amplify my peak but for some reason I get an error message

 ??? No appropriate method, property, or field FFTsignal2 for class dfilt.df2sos.

I am new to this filter and so I am not really sure if I using it correctly. I want to amplify a peak at 1Hz (or 1/30 if the frequency is normalised) and so I have used the following;

N = 8; F0 = (1/30); BW = 0.1; 
f = fdesign.peak('N,F0,BW',8,(1/30),.05,80);

Then I use: (tbh I am not sure what to use here because ideally I would like a nice tight peak)

Hd = design(f,'butter');

then to apply I use

FFTfilteredSignal = filter(Hd.FFTsignal2);