Surface plasmon resonance (SPR) spectroscopy is a label-free method for monitoring binding events among biomolecules in real time and for sensing applications.1 SPR spectroscopy has been widely used in chemistry, biochemistry, and biology research. Our objective is to achieve ultra-low level detection of small molecules that are important markers of cancer disease. Also, we are interested in monitoring pH changes in less abundant biological samples. As we know, pH is an essential parameter in biological, medical and industrial applications. Monitoring the pH level in biological fluids reflects the abnormal conditions in human body.2 , 3We will present our findings on sensitive detection of small molecules and amplification of SPR signals by using chemical indicators and detection by an SPR-array imager Acknowledgements.This project was supported by Oklahoma State University. 1. Fasoli, J. B.; Corn, R. M., Surface Enzyme Chemistries for Ultrasensitive Microarray Biosensing with SPR Imaging. Langmuir 2015, 10.1021/la504797z. 2. Sim, J.; Kwon, D.-S.; Kim, J., Acid-sensitive pH sensor using electrolysis and a microfluidic channel for read-out amplification. RSC Advances 2014, 4 (75), 39634-39638. 3. Kick, A.; Mertig, M., Characterization of pH-sensitive polymer layers by surface plasmon resonance and quartz crystal microbalance. physica status solidi (a), 2015, 10.1002/pssa.201431604.