Uncertainty budget for the ion chromatographic determination of fluoride and chloride in nuclear grade boron carbide and elemental boron employing ultrasound-assisted dispersive solid–liquid extraction

Abstract

A simple, rapid, and accurate method for the determination of trace level anionic impurities of fluoride and chloride in nuclear grade boron carbide and elemental boron is presented. The method involves ultrasound assisted dispersive solid–liquid extraction (UA-SLE) of fluoride and chloride from sample matrix, followed by determination of the analytes using ion exchange chromatography in suppressed conductivity mode. A Dionex IonPac AS11-HC anion exchange analytical column connected in series with an IonPac AG11-HC guard column has been employed for fluoride and chloride separation with 15 mM NaOH as the eluent. The limit of detection for fluoride and chloride is 1.0 and 2.0 µg g⁻¹, respectively, and the relative standard deviation is 4% for the method. The present analytical method has a higher throughput. The recovery of added anions was in the range of 93–105%. The method was validated using ASTM method of pyrohydrolysis and ion selective electrode analysis. The method developed, eliminated the use of chemical reagents required in the case of regular sample pretreatment procedures. An uncertainty budget is presented for analysis using bottom up approach. Major contributor to the combined uncertainty was found to be the calibration intercept and instrumental response in the case of fluoride and chloride, respectively.

Graphical Abstract

Keywords:

• Chloride
• fluoride
• ion exchange chromatography
• nuclear grade boron carbide and elemental boron
• suppressed conductivity detection
• ultrasound assisted dispersive solid–liquid extraction
• uncertainty budget

Acknowledgments

The authors would like to thank Dr. H. Pal, Associate Director, Chemistry Group, BARC for his constant support.