Thermocouple to ADC - with negative and positive voltages
You'll need to amplify the signal to the range your A/D can handle - there are existing parts for just this purpose.  F/ex, Analog Devices' AD595 thermocouple amplifier. Simplecircuitboards.com sells boards based on it.

For a more comprehensive solution, Maxim MAX6675 is a complete thermocouple conversion device (thermocouple in, digital out).  It's currently in "Not Recommended for New Designs" status by the manufacturer and I didn't see a recommended replacement but that may not matter if you're not designing it into a new product.  Adafruit Industries sells the part on a breakout board ready to plug into a breadboard.