A new analytical method for lead determination in atmospheric particulate matter by a combination of ultrasound-assisted extraction and supramolecular solvent preconcentration

摘要

Air pollution by lead, even in small concentrations, can cause serious health effects. In the atmosphere this element can generally be found in particulate matter (PM), and in general in small concentrations. This work proposes the development of an analytical method for lead determination in inhaled PM based on ultrasound-assisted extraction with subsequent supramolecular solvent based dispersive liquid-liquid microextraction (SM-DLLME), using reverse micelles of dodecanoic acid as an extractor dispersed in a continuous phase of tetrahydrofuran (THF)/water. The rich phase was then analyzed by thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) coupled on-line to a flow injection analysis (FIA). An analytical curve in the range of 15.0-200.0 g L-1 (R-2 = 0.999), an enrichment factor of 18.1 times and the limits of detection (LOD) and quantification (LOQ) equal to 3.7 and 11.3 g L-1, respectively, were obtained. The accuracy of the method was successfully attested by comparing with EDX analysis through the paired t-test at a confidence level of 95%. The amount of lead determined in the samples of PM collected in different environments varied from 19.3 to 94.8 ng m(-3).