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University Park, IL, United States

Sadi B.B.,Radiation Protection Bureau | Fontaine A.,Carleton University | McAlister D.,1955 University Lane | Li C.,Radiation Protection Bureau
Analytical Chemistry

A new radiobioassay method has been developed for simultaneous determination of 90Sr and 226Ra in a spot urine sample. The method is based on a matrix removal procedure to purify the target radionuclides from a urine sample followed by an automated high performance ion chromatographic (HPIC) separation of 90Sr and 226Ra and offline radiometric detection by liquid scintillation counting (LSC). A Sr-resin extraction chromatographic cartridge was used for matrix removal and purification of 90Sr and 226Ra from a urine sample prior to its introduction to the HPIC system. The HPIC separation was carried out through cation exchange chromatography using methanesulfonic acid (75 mM) as the mobile phase at 0.25 mL/min flow rate. The performance criteria of the method was evaluated against the American National Standard Institute ANSI/HPS N13.30-2011 standard for the root mean squared error (RMSE) of relative bias (Br) and relative precision (SB) at two different spiked activity levels. The RMSE of Br and SB for 90Sr and 226Ra were found to be satisfactory (≤0.25). The minimum detectable activity (MDA) of the method for 90Sr and 226Ra are 2 Bq/L and 0.2 Bq/L, respectively. The MDA values are at least 1/10th of the concentrations of 90Sr (190 Bq/L) and 226Ra (2 Bq/L) excreted in urine on the third day following an acute exposure (inhalation) that would lead to an effective dose of 0.1 Sv in the first year. The sample turnaround time is less than 8 h for simultaneous determination of 90Sr and 226Ra. (Figure Presented). © 2015 American Chemical Society. Source

Cariou R.,French National Institute for Agricultural Research | McAlister D.R.,1955 University Lane | Marchand P.,French National Institute for Agricultural Research | Fern M.J.,1955 University Lane | And 2 more authors.

Polychlorodibenzo-p-dioxins, polychorodibenzofurans and "dioxin-like" polychlorinated biphenyls are widespread persistent organic pollutants sharing a similar toxicological pathway mediated by the aryl-hydrocarbon receptor (AhR). Since the confirmatory method for their measurement at trace levels in complex matrices (using isotopic dilution and gas chromatography-high resolution mass spectrometry) remains time and cost-consuming, growing efforts of the scientific community have been focused on the development of screening approaches, including AhR mediated assays. Unfortunately, AhR ligands are highly diverse and agonistic/antagonistic effects can be observed on procedural blanks and/or sample extracts. In this study, the influence of solvent grade quality on the response of a DNA-binding AhR mediated assay used for screening dioxins has been investigated. Our results demonstrated a very critical impact of this parameter with both strong agonistic and antagonistic effects observed for any tested solvent lot. A small silver nitrate silica column removed partly these interfering compounds and then can be recommended as final purification step. Some preferable grades can be identified and selected in order to guarantee the best possible performances. However, it appears necessary to test every new lot, even if a grade appeared previously compliant. © 2009 Elsevier B.V. All rights reserved. Source

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