Species-specific isotope dilution (sometimes also called speciated isotope dilution) is an isotope dilution technique using a spike compound identical to the compound under investigation but labeled with a specific isotope of the target element. Species-specific ID analysis is only possible for element species well defined in their structure and composition. The equilibration of the spike and the analyte in the sample, attainable in classical IDMS by multiple sequential dissolution and evaporation cycles, cannot be guaranteed to be achieved for species-specific ID analysis of solid samples. If applicable, the method can correct for loss of analyte during sample preparation following the spike addition, incomplete derivatisation yield and for intensity suppression/enhancement during detection.