Abstract: Disclosed in this specification is a method for detecting an analyte using buoyant particles and chemical moieties to give buoyant particle composites that exhibit SERS and can be used for detecting the analytes in a liquid sample. A method is provided for detecting analytes of interest by contacting the analyte with a buoyant particle that comprises a first chemical moiety, such as a SERS-active component, allowing the analyte of interest to bind to the first chemical moiety. The resulting composite localizes in a discrete location of the liquid sample through a buoyant force. The composite is then detected by measuring the Raman scattered light in the discrete location of the liquid sample.