purification of mcpba

commercial mcpba contains ~77% mcpba. the rests are acids and water.
To get a 99% mcpba:

Purification of MCPBA
35 g MCPBA (Aldrich 57–86%) was dissolved in 250 ml ether
and washed with 3×150 ml buffer solution (410 ml 0.1 M
NaOH, 250 ml 0.2 M KH2PO4 made up to 1 l, pH 7.5).
The ether layer was dried over MgSO4 and carefully evapor-
ated under reduced pressure to give ca. 17 g pure MCPBA
(CAUTION! potential explosive).

reference:
J. Chem. Soc., Perkin Trans. 1, 1998 2771