The Texas Instruments (TI) TSPR1A170100 Spreetat liquid analytical sensor allows you to measure the refractive index of liquids that come in contact with the sensing surface. This measurement is obtained using an ultrasensitive physical principle known as surface plasmon resonance (SPR). Electrical connections are made via pins that protrude from the bottom of the device. The pin configuration is similar to a standard 16-pin dual in-line device. The following sections provide detailed information.