In order to study the dependence of superconductivity on sample preparation and the influence of cationic doping, Bi2Sr2Can-1CunO4+2n samples were prepared using various sintering temperatures and nominal starting compositions. After each sintering the samples were characterized with x-ray-diffraction and magnetic-ac-susceptibility measurements. In all cases the corresponding doped57 samples were also made for Mössbauer measurements. The Mössbauer measurements usually show three quadrupole components arising from the different phases in the samples. The site assignment of Fe57 is discussed.