How many episodes are in Pokemon master quest?

"Pokémon Master Quest" is not an official Pokémon series. It's possible you are referring to one of the following:

* Pokémon Masters EX: This mobile game has over 300 episodes (chapters), but it's constantly being updated with new content.

* Pokémon Mystery Dungeon: Red Rescue Team/Blue Rescue Team: These games include a "Master Quest" difficulty setting, but they are not structured with episodes.

Please clarify what you mean by "Pokémon Master Quest" so I can give you a more accurate answer.