Extraction of Beryllium from Refractory Beryllium Oxide with Dilute Ammonium Bifluoride and Determination by Fluorescence: A Multiparameter Performance Evaluation

Abstract

Beryllium exposure can cause a number of deleterious health effects, including beryllium sensitization and the potentially fatal chronic beryllium disease. Efficient methods for monitoring beryllium contamination in workplaces are valuable to help prevent dangerous exposures to this element. In this work, performance data on the extraction of beryllium from various size fractions of high-fired beryllium oxide (BeO) particles (from < 32 microm up to 212 microm) using dilute aqueous ammonium bifluoride (ABF) solution were obtained under various conditions. Beryllium concentrations were determined by fluorescence using a hydroxybenzoquinoline fluorophore. The effects of ABF concentration and volume, extraction temperature, sample tube types, and presence of filter or wipe media were examined. Three percent ABF extracts beryllium nearly twice as quickly as 1% ABF; extraction solution volume has minimal influence. Elevated temperatures increase the rate of extraction dramatically compared with room temperature extraction. Sample tubes with constricted tips yield poor extraction rates owing to the inability of the extraction medium to access the undissolved particles. The relative rates of extraction of Be from BeO of varying particle sizes were examined. Beryllium from BeO particles in fractions ranging from less than 32 microm up to 212 microm were subjected to various extraction schemes. The smallest BeO particles are extracted more quickly than the largest particles, although at 90 degrees C even the largest BeO particles reach nearly quantitative extraction within 4 hr in 3% ABF. Extraction from mixed cellulosic-ester filters, cellulosic surface-sampling filters, wetted cellulosic dust wipes, and cotton gloves yielded 90% or greater recoveries. Scanning electron microscopy of BeO particles, including partially dissolved particles, shows that dissolution in dilute ABF occurs not just on the exterior surface but also via accessing particles' interiors due to porosity of the BeO material. Comparison of dissolution kinetics data shows that as particle diameter approximately doubles, extraction time is increased by a factor of about 1.5, which is consistent with the influence of porosity on dissolution.

Field-portable methods for monitoring occupational exposures to metals

“…A modification of the procedure, in which longer-term extraction (4 hours) is carried out in a slightly higher concentration (3%) of aqueous ammonium bifluoride, enables quantitative extraction of larger particle sizes (up to >200 microns aerodynamic diameter) of high-fired beryllium oxide. 44 The method yielded acceptable recoveries from refractory BeO in several different sampling media tested.…”

NGSI FY15 Final Report. Innovative Sample Preparation for in-Field Uranium Isotopic Determinations

“…Gravity convection ovens employ a fan to rapidly distribute heat throughout the oven cavity providing a more uniform heat distribution and faster temperature equilibrium. It has been previously found, for beryllium analysis, that convection ovens provide faster and more efficient dissolution of beryllium oxide from industrial hygiene swipes 4 . To study the oven and sample temperature profiles, we inserted a calibrated thermocouple into the oven chamber and a second thermocouple was immersed in one tube of a sample digestion batch.…”

“…Interferences are identified and minimized by matrix matching of calibration standards and samples; filtration and dilution; use of daily performance check standards; and routine instrument maintenance. 4. Accurately pipette 10 ml of 1% (w/v) ABF into each tube 12.5.…”

Development and Validation of Analytical Methods for Ultra-Trace Beryllium in Biological Matrices

“…Given the high solubility of Be and BeAl powder in concentrated acid solutions (38), tests were carried out directly in the presence of organs, as reported in Table III. It is known that BeO particles formed at high temperatures (those used in the study) can only be dissolved under specific conditions (38,39). Therefore, as shown in Table III, H 2 SO 4 is required to ensure complete dissolution of particles and thereby obtain more accurate values in the unknown samples.…”