Transform strings into array or floats?

I have a problem: the user inserts two values, via graphical interface, separated by commas (I tested put in interface 10,0), and I need to transform these values into values that I can do accounts. I tried the code below, and I tested it by starting the first element (which should be 10.0), I get 1.0:

    for i in range(6):
        qx = str(self.tbCargaDist.item(i,0).text()) #captura string        
        qx.split(',') 
        qx = float(qx[0])
        print qx