Interlaboratory Evaluation of a Standardized Inductively Coupled Plasma Mass Spectrometry Method for the Determination of Trace Beryllium in Air Filter Samples

Abstract

A collaborative interlaboratory evaluation of a newly standardized inductively coupled plasma mass spectrometry (ICP-MS) method for determining trace beryllium in workplace air samples was carried out toward fulfillment of method validation requirements for ASTM International voluntary consensus standard test methods. The interlaboratory study (ILS) was performed in accordance with an applicable ASTM International standard practice, ASTM E691, which describes statistical procedures for investigating interlaboratory precision. Uncertainty was also estimated in accordance with ASTM D7440, which applies the International Organization for Standardization Guide to the Expression of Uncertainty in Measurement to air quality measurements. Performance evaluation materials (PEMs) used consisted of 37 mm diameter mixed cellulose ester filters that were spiked with beryllium at levels of 0.025 (low loading), 0.5 (medium loading), and 10 (high loading) microg Be/filter; these spiked filters were prepared by a contract laboratory. Participating laboratories were recruited from a pool of over 50 invitees; ultimately, 20 laboratories from Europe, North America, and Asia submitted ILS results. Triplicates of each PEM (blanks plus the three different loading levels) were conveyed to each volunteer laboratory, along with a copy of the draft standard test method that each participant was asked to follow; spiking levels were unknown to the participants. The laboratories were requested to prepare the PEMs by one of three sample preparation procedures (hotplate or microwave digestion or hotblock extraction) that were described in the draft standard. Participants were then asked to analyze aliquots of the prepared samples by ICP-MS and to report their data in units of mu g Be/filter sample. Interlaboratory precision estimates from participating laboratories, computed in accordance with ASTM E691, were 0.165, 0.108, and 0.151 (relative standard deviation) for the PEMs spiked at 0.025, 0.5, and 10 microg Be/filter, respectively. Overall recoveries were 93.2%, 102%, and 80.6% for the low, medium, and high beryllium loadings, respectively. Expanded uncertainty estimates for interlaboratory analysis of low, medium, and high beryllium loadings, calculated in accordance with ASTM D7440, were 18.8%, 19.8%, and 24.4%, respectively. These figures of merit support promulgation of the analytical procedure as an ASTM International standard test method, ASTM D7439.

Trace beryllium determination in polyvinyl alcohol wipes by extraction and fluorescence detection: interlaboratory analysis

“…These precision estimates are acceptable in consideration of an overall goal of interlaboratory RSDs less than 20%. 10,11,19 They also compare favorably with interlaboratory RSDs obtained from the Beryllium Proficiency Analytical Testing Program (BePAT) of the American Industrial Hygiene Association (AIHA), which are typically in the realm of 10-20%. 20 Estimated Be recoveries were between 90% and 100% for dry PVA wipes (Table 1) and spanned from z87% to z93% for wetted wipes after mathematically correcting for their background water content of 0.50 AE 0.01 mL ‡ (Table 2).…”

“…8,9 The methodology enables attainment of detection limits of less than 1 ng Be per sample, and compares favorably with the performance of the highly sensitive atomic spectrometric technique, inductively coupled plasma mass spectrometry (ICP-MS). 10,11 Besides cellulosic wipe sampling media, wipes comprised of polyvinyl alcohol (PVA) have been used extensively for surface dust sampling and subsequent determination of Be by atomic spectrometric methods. 12 However, the use of PVA wipes for surface sampling, in concert with NH 4 HF 2 extraction and HBQS fluorescence detection of Be, has not been fully evaluated.…”

Atomic spectrometry update. Environmental analysis

“…Marelli et al 361 proposed an alternative protocol for measuring 63 Cu/ 65 Cu ratios by ICP-QMS. Their modified bracketing approach incorporated regular monitoring of a blank solution, which was used to compensate for long-term drift in signal sensitivity.…”

Optical molecular fluorescence determination of ultra-trace beryllium in occupational and environmental samples using highly alkaline conditions

“…2, 3 It has been shown in previous work that a molecular fluorescence detection technique using hydroxybenzoquinoline sulfonate (HBQS) as fluorophore, 4 after sample dissolution in dilute ammonium bifluoride (NH 4 HF 2 ), 5 offers method detection limits (MDLs) which are low enough to allow for accurate Be measurements at levels well below current OELs in the United States and Europe. 6,7 Adequately low Be MDLs for current OELs in the U.S. are also provided by graphite furnace atomic absorption spectrometric (GFAAS) 8 and inductively coupled plasma mass spectrometric (ICP-MS) 9 methods after digestion of samples in appropriate dissolution reagents. 10 …”