Quantification of ytterbium in road dust applying slurry sampling and detection by high-resolution continuum source graphite furnace atomic absorption spectrometry

Abstract

In this work, the determination of ytterbium in road dust samples, employing a simple and fast methodology, based on sample preparation as slurry and analysis by high resolution-continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS), is purposed. The determinations were carried out on the Yb main line, 398.799 nm, using an integration time of 5.0 s. The optimum condition for the slurry preparation of road dust samples was established through a Doehlert matrix for two variables, which employed a HNO3 concentration of 0.24 mol L−1 and homogenization time of 34 min, using ultrasonic bath. The temperatures applied to the graphite furnace were optimized, wherein the pyrolysis and atomization temperatures were 1200 °C and 2700 °C, respectively, using 250 μg of W as permanent chemical modifier. To investigate possible matrix interferences in the determination of Yb in road dust samples, external calibration and standard addition curves were compared. The comparison between slopes of the external and standard addition calibration curves showed difference of about 7.0%, an indication of absence of matrix effects for determination of Yb in road dust samples. The limit of detection (LOD) and limit of quantification (LOQ) were 22 and 72 ng g−1, respectively, with a characteristic mass of 6.0 pg. The accuracy was confirmed through analyses of three certified reference materials (CRM): Trace Elements in Soil Containing Lead From Paint (NIST 2586), Rock (NCS DC 73301) and Geochemical Soil (TILL-1), and the good agreement between the found and certified values was obtained, 99 ± 4 to 104 ± 2%, corroborating the accuracy of the analytical method. The precision was expressed as relative standard deviation (RSD) for measurements in triplicate, being lower than or equal to 10.0%. The analytical method was used for Yb determination in eight samples of dust collected in an urban area of Salvador and Jaguaquara, Bahia State, Northeast, Brazil. The concentrations obtained for Yb ranged from 172 ± 13 to 2065 ± 122 ng g−1. Thus, the proposed analytical method presents the characteristics of being fast, precise and accurate for the determination of Yb in road dust samples, employing slurry sampling and detection by HR-CS-GFAAS.