Validation of a standardized portable fluorescence method for determining trace beryllium in workplace air and wipe samples

Abstract

Beryllium is widely used in industry for its unique properties; however, occupational exposure to beryllium particles can cause potentially fatal disease. Consequently, exposure limits for beryllium particles in air and action levels on surfaces have been established to reduce exposure risks for workers. Field-portable monitoring methods for beryllium are desired in order to facilitate on-site measurement of beryllium in the workplace, so that immediate action can be taken to protect human health. In this work, a standardized, portable fluorescence method for the determination of trace beryllium in workplace samples, i.e., air filters and dust wipes, was validated through intra- and inter-laboratory testing. The procedure entails extraction of beryllium in 1% ammonium bifluoride (NH(4)HF(2), aqueous), followed by fluorescence measurement of the complex formed between beryllium ion and hydroxybenzoquinoline sulfonate (HBQS). The method detection limit was estimated to be less than 0.02 microg Be per air filter or wipe sample, with a dynamic range up to greater than 10 microg. The overall method accuracy was shown to satisfy the accuracy criterion (A< or = +/-25%) for analytical methods promulgated by the US National Institute for Occupational Safety and Health (NIOSH). Interferences from numerous metals tested (in >400-fold excess concentration compared to that of beryllium) were negligible or minimal. The procedure was shown to be effective for the dissolution and quantitative detection of beryllium extracted from refractory beryllium oxide particles. An American Society for Testing and Materials (ASTM) International voluntary consensus standard based on the methodology has recently been published.

The bioinorganic chemistry and associated immunology of chronic beryllium disease

“…HBQS is an extraordinary ligand even at pH 12 and is part of a commercial beryllium detection system that can selectively detect beryllium at concentrations <1 nM. 35,36 In order to understand if there was any commonality between the binding of monomer and polynuclear binding ligands we re-examined the binding of Be to a wide variety of monomeric ligands. After considering Be binding across a wide range of ligands and careful reexamination of the proton NMR spectra of the polynuclear ligands in aprotic media, we have proposed a new binding concept that focuses on the comparison of beryllium to H + .…”

High Sensitivity Low Fluorescence Detection for Beryllium Particulates SBIR Phase I Final Report ER84587

“…The method is based on the fluorescence of beryllium bound to hydroxybenzoquinoline sulfonate (HBQS) 9 , and includes a dissolution technique using dilute ammonium bifluoride solution 10,11 . Dilute ammonium bifluoride has been proposed as a field extraction medium which is much less hazardous than the strong acids used ordinarily in digestion of beryllium samples in the laboratory.…”

“…Currently, the beryllium sample is dissolved in 5 ml of ammonium bifluoride, of which 0.1 ml is added to 1.9 ml of buffered HBQS solution 10,11 . In this process, only 2% of the available beryllium sample is used.…”

Chapter 7. Beryllium Analysis by Non-Plasma Based Methods

“…16,17 Iron and titanium impart a yellow color to the final solution; these tend to precipitate in a few hours and can be removed by filtration once the solutions become clear. 6,18 Figure 7.3 shows the excitation spectrum of a measurement solution comprising one part of 1% ABF solution with different concentrations of beryllium when mixed with 19 parts of the dye solution as outlined in the standard NIOSH and ASTM International methods. The dye solution was prepared by the addition of 12.5 mL of 10.7 mM EDTA and 25 mL of 107 mM L-lysine monohydrochloride to 3 mL of 1.1 mM 10-HBQS.…”

“…In developing the standard test method, it has been demonstrated that the procedure results in good agreement when the data from different labs are compared, and, as expected, other metals do not interfere with the analysis. 6,18 To check on non-interference, some of the metals were added in concentrations in excess of 50 000 fold as compared to beryllium. The sensitivity of the system is dependent on many factors including the ratio of the dissolution solution (with beryllium) and the dye solution.…”