Arduino Uno & 24 Bit ADC - 2's Compliment to Binary conversion

Is this what you're trying to do?

count=count^0x800000;         // convert 24 bit ADC two's comp output as follows

  // two's comp min =  0x800000 = -8388608; converted = 0
  // two's comp zero = 0x000000 =        0; converted = 2^23 = 8,388,608
  // two's comp max =  0x7FFFFF = +8388607; converted = (2^24)-1 = 16,777,215

PS: your post title is confusing... it says you want convert two's complement to BINARY. It seems you actually want to convert and shift two's comp to a positive DECIMAL. But your post is confusing as well. So who knows.......