Dosy expts are quite sensitive to conditions and may easily give wrong results. When doing the fit, check if the points are deviating in a random manner from the fitted curve, discard your experiment otherwise. (obs: VnmrJ does show you the fit graph).
There is no other way to know if you have a reasonable fit or a curve trying to fit crazy points. Thus if you use topspin you better plot the data in a math program as well. I have experienced some strange behaviour of topspin distributing data points in incomprehensible manner. If you are interested in checking the quality of your fit however, you better get the data points from MestreNova and plot it yourself (intensities Vs gradients plot, I mean). Mestrenova will do nice 2D plots of Dosy for you, what helps a lot to identify different substances.
