I would do biceps on the same day as chins, triceps on the same day as chest. It looks like you're double hitting your arms each week with chins & curls, and press & tricep work, could you not hit your major exercises twice as well by putting exercises together as I suggested? Maybe doing it the way you are isn't such a bad idea, though.
Too much bicep volume in there .. or so it seems to me. Chins do a lot for your biceps by the way... My 1rm curl when I first tried it was 50kg, just from doing lots of chins. I do 3-4 sets (max) of barbell curls after chin ups and I could probably curl almost 60kg now.
My 2c..