Reagecon's Copper Standard 4 µg/mL (4 ppm) in 2-5% Nitric Acid (HNO₃) for ICP or ICP-MS is manufactured from ultra-pure metal (99.999%) and it is tested by an ISO17025 Accredited Test Method (INAB Ref: 264T). The raw material used in this standard is assayed by titration and ICP-MS prior to manufacture. Separate standards are used to control or calibrate the titration and ICP-MS respectively. This product is manufactured gravimetrically using the mass balance approach: 100% less the sum of all impurities (w/w). Prior to bottling, the final product is tested and verified using ICP-MS and is reported using the gravimetric result, corrected for density. To as specification of ± 0.2%. The results are reported in mg/kg and mg/L on the basis of weight and density. Reagecon hold ISO/IEC 17025 accreditation for calibration of laboratory balances (INAB Ref: 265C). All of the volumetric, titrimetric and gravimetric functions are carried out under a highly regulated temperature regime. Reagecon hold ISO/IEC 17025 for Temperature Calibration in the range of -90 °C to 650 °C (INAB Ref: 265C) and ISO/IEC 17025 Accreditation for density measurement using Oscillating U-Tube and Bingham Pycnometry Methods (INAB Ref: 264T).