Accurate and precise zinc isotope ratio measurements in urban aerosols

Summary, in English

We developed an analytical method and constrained procedural boundary conditions that enable accurate and precise Zn isotope ratio measurements in urban aerosols. We also demonstrate the potential of this new isotope system for air pollutant source tracing. The procedural blank is around 5 ng and significantly lower than published methods due to a tailored ion chromatographic separation. Accurate mass bias correction using external correction with Cu is limited to Zn sample content of approximately 50 ng due to the combined effect of blank contribution of Cu and Zn from the ion exchange procedure and the need to maintain a Cu/Zn ratio of approximately 1. Mass bias is corrected for by applying the common analyte internal standardization method approach. Comparison with other mass bias correction methods demonstrates the accuracy of the method. The average precision of δ⁶⁶Zn determinations in aerosols is around 0.05‰ per atomic mass unit. The method was tested on aerosols collected in São Paulo City, Brazil. The measurements reveal significant variations in δ⁶⁶Zn_Imperial ranging between -0.96 and -0.37‰ in coarse and between -1.04 and 0.02‰ in fine particular matter. This variability suggests that Zn isotopic compositions distinguish atmospheric sources. The isotopic light signature suggests traffic as the main source. We present further δ⁶⁶Zn_Imperial data for the standard reference material NIST SRM 2783 (δ ⁶⁶Zn_Imperial) 0.26 (0.10‰).

• Author: Simone Gioia; Dominik Weiss; Barry Coles; Tim Arnold; Marly Babinski
• Publishing year: 2008-12-15
• Language: English
• Pages: 9776-9780
• Publication/Series: Analytical Chemistry
• Volume: 80
• Issue: 24
• Links: http://dx.doi.org/10.1021/ac8019587
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Status: Published
• ISBN/ISSN/Other: ISSN: 0003-2700