[305152] Artigo – CBM – Congresso Brasileiro de Metrologia

Resumo: MRC 8757.0001, a single-element potassium calibration solution, was prepared and certified at Inmetro. The Certified Reference Material (CRM) was gravimetrically prepared with an internally certified high-purity potassium chloride in an acidified aqueous solution. The batch consisted of 152 units, packed in a 125 mL capped polypropylene bottle, protected with a polypropylene bag and an aluminized pouch. Certification studies were performed according to ISO GUIDE 35, ISO 17034 and internal standards. High-Performance Inductively Coupled Plasma Optical Emission Spectrometry (HP ICP OES) was applied as a measurement method. The certified potassium mass fraction was 1002 mg/kg, with an expanded uncertainty of 11 mg/kg, considering a coverage factor of k = 2.02 for a confidence level of approximately 95 %. With HP ICP OES we improved the production and certification of calibration solutions by diminishing the expanded uncertainty of MRC 8757.0001 to up to 47 %, when compared to another calibration solution prepared at Inmetro.