This is a combined synopsis and solicitation for a single-award, indefinite-delivery, indefinite-quantity (IDIQ) contract with fixed-price task orders. The contract will provide isotope analysis support to the Global Monitoring Laboratory (GML) in Boulder, CO. The acquisition is not set aside for small businesses. Detailed requirements are outlined in the attached Performance Work Statement (PWS), and pricing is to be submitted using the provided pricing schedule. Acceptance terms are f.o.b. destination.