SPEX CertiPrep Claritas PPT® standards are a class of Inorganic Certified Reference Standards designed specifically for today's new generation of trace ICP and ICP-MS instrumentation. Based on extensive development, our chemists have formulated this line of high-purity standards for user convenience and stability. Our Claritas PPT® selection of standards includes a complete series of multi-element solutions, many designed for use with US EPA Methods. These solutions are made with the highest purity materials available and are tested on our state-of-the-art ICP-MS. SPEX CertiPrep Certified Reference Materials (CRMs) are manufactured under a quality system complying with the requirements of ISO 9001, ISO/IEC 17025 and ISO 17034. To identify or confirm the maximum concentration of an analyte that does not cause a memory effect greater than the contract required detection limit (CRDL). The test solutions are not analyzed directly; equal volumes of the two are mixed and then introduced into the instrument for a normal sample exposure time. A blank is then run to confirm that all analyte memory effects are below the CRDL.