PRODUCT LIST

Isotopic Standards.

ISC-Science offers a wide range of monoelemental Isotopic Standards designed for quantitative analysis by Isotope Dilution Inductively Coupled Plasma Mass Spectrometry (ID-ICP-MS) with concentrations from 10 mg/g to 100 mg /g.

• • The isotope standards are certified in concentration and abundances using the primary method Isotope Dilution in accordance with ISO 17034.
  • The certified concentrations and isotopic abundances values are traceable to primary standards from NIST and SI to ensure the highest accuracy and complete traceability.
  • The standards are manufactured from high purity starting materials, high purity acids and 18-MΩ deionized water.
  • A Certificate of Analysis enclosed with each material provides detailed information on the contents including uncertainty budget, concentration, isotopic abundances, traceability, release date and minimum shelf life.

How Isotopic Standards are charaterized?

Abundance values are expressed as percentage [molar fraction (*100), %] and concentration values as micrograms of the element per gram of solution (μg/g). Based on ISO 17034 and ISO/IEC 17025, the certified concentration value is determined gravimetrically from a solution characterized by ICP-MS using a reference method in a single laboratory [isotope dilution and mass spectrometry (iD-MS)], and certified abundance values are determined by measuring the isotopic ratio of all isotopes of the element via ICP-MS using the enriched isotope of the corresponding element as a reference. The expanded uncertainty for each value is determined as U = 2 · u, where k = 2 is a coverage factor for a 95% confidence interval and u is the combined uncertainty calculated according to ISO Guide 35. The value of u attempts to represent the combined effect of different contributions to uncertainty associated with gravimetric preparation, ID-MS determination, homogeneity, and stability for concentration values, and ICP-MS determination for abundance values.