Ways to detect a vinyl rip

Use your ears

Use monitors or headphones and listen to the full track. Pay close attention to the very beginning, end, and any breakdowns in the track and listen out for vinyl noise, cracks or clicks.

This is the most effective way to determine a rip and although most rippers clean their files (to reduce noise or clicks) there is usually still giveaways. Cleaned up rips may lack a lot of the lower end frequencies and sound quite flat/lack depth, but masters will always sound full and crisp.

It is also possible that artists add vinyl noise to their masters, so be careful of that. Despite that, it is usually easy to determine masters from rips after enough careful listening.

Use Rekordbox/alternative analysis software

Another big giveaway is the BPM of the tracks. Most real masters will be .00 or .50 (with a few VERY rare exceptions of .99 or .01)

Most rips will not have an exact bpm, and can be anything (.98, .76, .08, .32 etc)

Also pay attention to the grid of the track, master files will have perfectly consistent and accurate BPM whereas some rips may drift and slow down/speed up at times. Rips can also have a fixed/consistent speed, it depends on the ripping set up.

Spectrogram analysis (unreliable)

A quick test for determining masters is using the spek program, digital masters/promos usually don't reach the top of the box, leaving some black area above the colouring.

Rips will always reach the top, having minimal/no black space at the top. This isn't guaranteed though as some masters can also reach the top.

Thanks @wockbread for presented article