Recommendation: I am sure about MANY (good to excellent) recipes and methods out in the world wild..wide web... (e.g. Google search for

First shot / trial cf.

ftp://ftp.sonic.net/pub/users/lhund/Lotte/Postek/Postek5_175-216.pdf

pp.182-186: 7 different  methods (1970-1976).

If you can't access, reply and I shall provide the pdf.

Best wishes and good luck.

Forgot to add another, previous posting thread in RG (March 8,2013):

https://www.researchgate.net/post/What_is_the_best_way_of_preparation_of_algal_cells_for_SEM

Sir, Can you forward that PDF  for diatom preparation for  SEM 

Dear Jayachandran, here you go ....

best of luck,

Wolfgang