Write/read sd card under interrupt control?

I have an arduino 2560 application where I sample an analog signal at regular intervals and write the data to an sd card.

Timing and a/d converter run under interrupt control, and I also want to write the data in the same fashion, i.e. start a write and then return to the main program immediately.

As of now, every rec.write to the SD card takes around 840 microseconds. I would like to do something useful during that time, so I would like to just start a write, and the get an interrupt when the card module has completed.

Is this possible with the standard SdFat library (or any other library), and has anyone done that?