Determination of silver in airborne particulate matter collected on glass fiber filters using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sampling

The present work aims at the determination of silver in airborne particulate matter (APM) collected on glass fiber filters using direct solid sampling and high-resolution continuum source graphite furnace atomic absorption spectrometry. The secondary line at 338.289 nm was used for all measurements. A manual solid sampling accessory and solid sampling platforms were used for sample introduction. A mass of 400 mu g of ruthenium was thermally deposited on the platform surface as permanent modifier. The optimum pyrolysis and atomization temperature was 1,000 and 2,000 degrees C, respectively. Aqueous standard solutions were used for calibration exclusively. The analytical parameters obtained for the proposed method were as follows: characteristic mass, 4.4 pg Ag; detection limit (3 sigma, n = 10), 17 ng g(-1); and quantification limit (10 sigma, n = 10), 58 ng g(-1). These limits are equivalent to 0.05 and 0.16 ng m(-3), respectively, for 0.36 mg of sample mass (filter + APM) and an average volume of 1,440 m(3) air that had passed through the filter. The certified reference material urban particulate matter, NIST 1648, was used for checking the accuracy. Four filter samples with APM collected in Buenos Aires, Argentina, were analyzed. According to our study, the concentration of silver (average +/- confidence interval at 95% level, n = 5) varied between 0.64 +/- 0.06 and 1.18 +/- 0.07 mu g g(-1). corresponding to 1.99 +/- 0.11 and 4.54 +/- 026 ng m(-3). The precision, expressed as relative standard deviation, varied between 1.6 and 7.1% (n = 5). The analytical method proved to be simple, fast and reliable. (C) 2012 Elsevier B.V. All rights reserved.