Where Does My Coffee Come From? Hydrogen and oxygen stable isotope measurements on roasted coffee samples trace the origin of coffee beans based on unique trends observed from their isotopic fingerprints. How Can Stable Isotopes Trace Pollution Sources? Isotope Ratio Mass Spectrometry detects the “isotope fingerprint” of a sample, a unique chemical signature that changes from sample to sample across the environment. Where Does PM2.5 in Air Pollution Come From? The measurement of carbon, nitrogen, and sulfur isotope fingerprints of PM2.5 particles on quartz filter papers allows source identification. How Do Isotope Fingerprints Support Forensic Investigations? Isotope fingerprints allows forensic investigators to have a unique characterization of sample material and trace reactants, chemical pathways and reaction conditions. Tracing the Geographical Origin of Cocaine Analysis of cocaine seized from an “aircraft drop” in Uruguay led to the discovery of a previously unknown coca growing region in northern Bolivia. How Do Isotope Fingerprints Support Doping Control Investigations? Analyzing isotopes of the steroids provide characteristic isotope fingerprints of urinary steroids and offer a discrimination framework.