Purification of protozoa
Cryptosporidium parvum and Cryptosporidium meleagridis oocysts have been purified from fecal matter, usually from bovine or porcine sources, generally in simple two-layer Nycodenz® gradients [2- 9], although for the partial separation of Type 1 and Type 2 oocysts linear gradients of the same solute have been used .
Chesnot and Schwartzbrod  noted that Nycodenz® gradients were superior to those of Percoll® for oocyst purification, when considering both “recovery and particulate load”.
Nycodenz® solutions have been made up either in phosphate-buffered saline  or water ; there will
be a small difference in density between the two types of solvent, but otherwise it is unlikely that the
solvent will have any significant effect on the separation.