A highly basic dye solution without lysine was prepared as follows: 1. To this After mixing, a clear yellow solution was obtained; this had a measured pH of These dye solutions were found to be stable by pH and fluorescence measurements for at least twelve months. To investigate optimized analytical conditions, a suite of experiments was carried out in order to characterize the performance of the ultra-trace Be fluorescence measurement methodology in lysine-free and lysine-containing dye solutions.
Of particular interest were comparisons of the analysis results obtained between HBQS dye with and without lysine described above, as well as performance studies on a new workplace air sampling apparatus i. The lysine-free dye solution was able to tolerate more added acid i.
Both the NH 4 HF 2 and lysine neutralize the hydroxide used in the preparation of the dye solutions, such that more NH 4 HF 2 can be added to lysine-free solutions before there are any significant changes in pH. These results are important analytically as it is desired to maintain very high pH for optimal fluorescence of the HBQS-Be adduct.
Open diamonds: lysine-free dye solution; closed squares: dye solution contains lysine. These solutions were subjected to fluorescence measurements, with results uncorrected for background shown in Figure 2. It can be seen that the fluorescence signal remains high for lysine-free solutions at much higher NH 4 HF 2 content vs.
HBQS dye solutions containing lysine. Figure 3 shows the dependence of fluorescence intensity on the pH of dye solutions with and without beryllium. The results from both lysine-containing and lysine-free dye solutions do not show a rapid decrease in fluorescence intensity above a pH of about A rapid drop in fluorescence intensity is observed at a pH value of about 11 and below Figure 3. For comparison, the change in fluorescence with pH data from Matsumiya et al. Since this is relative fluorescent intensity, the data of Matsumiya et al. When we carried out more detailed analysis we observed a very different trend between data from this study and the results of Matsumiya et al.
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First there was no sharp drop-off the fluorescent intensity at higher alkalinity i. As a practical guideline the pH of the mixture of the acidic extraction solution and the dye solution should be about 12 or higher for effective determination of beryllium by this method. This demonstrates that lysine-free HBQS dye solution can be used with highly acidic starting solutions, a decided advantage for certain samples requiring stronger NH 4 HF 2 concentrations for effective extraction of Be prior to fluorescence analysis. In all cases, the fluorescence intensity resulting from the HBQS-Be adduct when using excitation at nm was about double that obtained with excitation at nm.
Open circles and diamonds: lysine-free dye solution blank solution and Be-containing, respectively ; closed triangles and squares: dye solution contains lysine blank and containing Be, respectively. Open pentagons represent data from Reference 4 Matsumiya, et al. Dye solutions described above i.
This is a benefit of the use of highly alkaline conditions sans lysine throughout the measurement process. Method detection limits MDLs for Be were estimated by analyzing ten blank media and reporting the MDL as three times the standard deviation of the mean blank signal. Batches of filters were prepared and analyzed in the presence of soluble Be 5 at low concentrations 0. Also, filters spiked with high-fired beryllium oxide BeO were subjected to sample preparation and fluorescence analysis. Solutions were analyzed by mixing with highly alkaline lysine-free dye solution and also with dye solution which contained lysine.
Analytical figures of merit for fluorescence analysis of Whatman filters media blanks and in 0. Analytical figures of merit for fluorescence analysis of MCE filters media blanks and in 0. In another set of experiments, mm diameter cellulosic sampler inserts consisting of MCE filters melded to cellulose acetate housings for insertion into mm air-sampling cassettes: Solu-Serts 28 were tested. The Solu-Serts were spiked using pre-determined quantities of NH 4 HF 2 solutions containing soluble beryllium and dried. Blank media as well as spikes were evaluated in a similar manner as that described earlier for surface sampling media.
The fluorescence values were corrected for any background contributed by the blank sampling media. The spiked filters were obtained commercially. Beryllium in the calibration solutions was 0, 0. The results on the spiked samples in Table 5 show excellent agreement with the expected values. Experiments were carried out to investigate if there would be any effect of interference from other metals besides Be when using highly alkaline solutions.
Iron Fe was chosen for these trials as it has been shown in the past that this element and also to some extent titanium can cause interference to the fluorescence measurement of the HBQS-Be adduct by imparting a yellow color to the measurement solution. In one set the solutions were immediately filtered through Acrodisc GHP mm syringe filters with hydrophilic polypropylene 0.
Another set of solutions was left standing for two hours and then filtered using similar filters. Control samples with the same concentration of beryllium but without Fe were also measured. In each series i. In all of the solutions mixtures of the dye and the sample solutions the Be concentration was 0.
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In each case the Fe concentration was more than 10, times the Be concentration. The results of these experiments are shown in Table 6 , and demonstrate that Fe interference to Be fluorescence measurement can be effectively eliminated in lysine-free as well as lysine-containing 5 HBQS dye solutions. Experiments were conducted on representative CRM soils to investigate the performance of the two dye solutions i. The pH of the dye solution with lysine mixed with the sample solution was 9.
These trials demonstrate that the use of highly alkaline conditions can enable the measurement of low levels of beryllium in bulk environmental samples such as soils. The experiments described herein show that there are several advantages in using highly alkaline, lysine-free HBQS dye solutions for trace and ultra-trace measurement of Be in occupational and environmental samples. The results are important in consideration of very low occupational exposure limits for Be that have been established globally and in newly-promulgated regulations in the US.
The extremely low method detection limits for Be will enable short-term airborne workplace exposures to be reliably monitored by means of a field-portable technique. The method offers promise for applications to a wider range of acidic extraction solutions, which could potentially be used to extract Be from challenging metallic samples such as aluminum and specialty alloys as well as ceramic materials. All web addresses referenced in this document were accessible as of the submission date of the original manuscript.
Recent Activity. Improved attributes include the ability to further enhance the detection limits of Be in extraction solutions of high acidity with minimal dilution, which is particularly beneficial when NH4HF2 solutions of higher concentration are used for extraction of Be from soil samples. The snippet could not be located in the article text. This may be because the snippet appears in a figure legend, contains special characters or spans different sections of the article. Int J Environ Anal Chem. Author manuscript; available in PMC Mar PMID: Cronin , a and Kevin Ashley b.
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Agrawal, K. Ashley: ten. Copyright notice. Abstract Exposures to beryllium Be , even at extremely low levels, can cause severe health effects in a percentage of those exposed; consequently, occupational exposure limits OELs promulgated for this element are the lowest established for any element.
Introduction Beryllium Be is an extremely useful but highly toxic element that is a key constituent in numerous materials such as high-performance ceramics, composites and specialty alloys. Results and Discussion To investigate optimized analytical conditions, a suite of experiments was carried out in order to characterize the performance of the ultra-trace Be fluorescence measurement methodology in lysine-free and lysine-containing dye solutions.
As increasingly stringent regulations and safety protocols have greatly decreased incidents of acute beryllium exposure, the need for ultrasensitive analytical techniques to monitor chronic low-level exposure has become greater. Testing for these particulates is not easy, and involves difficult standards of sample preparation and analysis.
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Proven performance is the best indicator of future success and we have a world of expertise when it comes to trace metals analysis. Furthermore, the BePAT Program highlights one of many intersections of our areas of expertise—our understanding of industrial hygiene and occupational exposures, our trace metals analysis experience, and our experience in the design and administration of laboratory proficiency testing programs.
Good data yield good decisions. It is critical that analytical laboratories generate repeatable and comparable beryllium analysis data in order to accurately monitor exposures over time. Our scientists review and evaluate lab results to ensure accuracy and verify components and concentrations. Our reports act as a reference for the labs to ensure results are accurate. As we continue to gather data from participating laboratories, we are collecting information about the analytical methods and sample preparation procedures that perform best.
This, in turn, empowers qualified professionals to conduct better beryllium analyses. It is important to remember that these proficiency tests not only ensure that laboratories are competent to determine the presence of beryllium particulates in industrial settings. In the long term, our work supports efforts to ensure that people who are exposed to beryllium do not bring the harmful trace metal home on their clothes, in their vehicles, or on their person.
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