The subject invention provides methods, assays and products for detecting small-molecules in a sample, in particular, in both clinical and field settings. The method for detecting a small-molecule target in a sample comprises providing a sample, contacting the sample with an aptamer-based sensor selective for the small-molecule target, and sensitively and rapidly detecting the small-molecule target in the sample. Specifically, the method utilizes EATR-amplified small-molecule sensors based on cooperative binding split aptamers (CBSAs).