On-line determination of water-soluble zinc in airborne particulate matter using a dynamic extraction procedure coupled to flame atomic absorption spectrometry

Abstract

In this work a flow injection procedure with FAAS detection for the on-line determination of water-soluble Zn in airborne particulate matter samples is presented. The method is based on a preliminary extraction of samples with water under dynamic conditions and the subsequent on-line FAAS measurement of the dissolved fraction of Zn. As compared to traditional batch-wise systems, the developed on-line extraction procedure offers enhanced sensitivity and sample throughput, reduced risk of sample contamination and the absence of metal redistribution or readsorption processes. With the use of two filter punches (diameter 9 mm) for analysis an instrumental detection limit of 2 ng Zn was obtained, which translates to a method detection limit of approximately 0.4 ng m⁻³ when considering the volumes of air collected per investigated aerosol sample. The reproducibility of analysis given as the relative standard deviation was 2.6% (n = 6). The procedure was applied for analysis of water-soluble Zn in aerosol samples from two urban sites in Austria. Accuracy of derived results was confirmed by analysis of the same sample set with a traditional batch-wise extraction approach as well as mass balance determination.