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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Calcium isotope determination in urine samples via the monitoring of (CaF)-Ca-44 and (CaF)-Ca-40 molecules by high-resolution continuum source graphite furnace molecular absorption spectrometry

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Author(s):
Zanatta, Melina B. T. [1] ; Nakadi, V, Flavio ; Resano, Martin [2] ; da Veiga, Marcia A. M. S. [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Dept Chem, FFCLRP, Av Bandeirantes 3900, BR-14040901 Ribeirao Preto, SP - Brazil
[2] Nakadi, Flavio, V, Univ Zaragoza, Dept Analyt Chem, Aragon Inst Engn Res I3A, Pedro Cerbuna 12, Zaragoza 50009 - Spain
Total Affiliations: 2
Document type: Journal article
Source: Journal of Analytical Atomic Spectrometry; v. 34, n. 11, p. 2280-2287, NOV 1 2019.
Web of Science Citations: 0
Abstract

This study investigates the possibility of obtaining Ca isotopic information by monitoring the absorption spectrum of a diatomic molecule generated in a graphite furnace using a high-resolution continuum source spectrometer (HR CS GFMAS). The method proposed enables calcium isotopic analysis using CaF as the target species. The difference in wavelength between (CaF)-Ca-40 (maximum at 628.534 nm) and (CaF)-Ca-44 (maximum at 628.191 nm) absorption signals was found to be 337.8 pm, evidencing that both species can be determined simultaneously. The method developed relies on the determination of Ca-40 and Ca-44 concentrations based on calibration functions specific to each isotope and makes use of 12 mu g of F as a molecule forming element without further chemical modifiers. The sensitivity of the method depends on the pH. It increases at pH values close to 2, and decreases until reaching a plateau at pH 6. The characteristic mass found for (CaF)-Ca-40 was 0.11 mu g for solutions with pH 2 and 0.18 mu g for alkaline solutions. The respective limits of detection were 1 and 2 mg L-1. The method was applied to the analysis of three urine samples, spiked with different Ca-40 and Ca-44 amounts. Due to chlorine interference, before the analysis of urine, calcium must be separated from the samples by precipitation with ammonium oxalate. Recovery tests provided results between 95 and 109%, highlighting the potential of the method for Ca-40 and Ca-44 determination in tracer experiments. (AU)

FAPESP's process: 17/20707-2 - High resolution continuum source of molecular absorption spectrometry for isotopic monitoring of calcium in fortified foods, serum and urine
Grantee:Márcia Andreia Mesquita Silva da Veiga
Support Opportunities: Scholarships abroad - Research