BONGIOVANNI guillermina Azucena
congresos y reuniones científicas
Comparison between different methods in dust air on polycarbote filters analysis by XRF using synchrotron radiation.
Arica, Chile
Conferencia; X Seminario Latinoamericano de Análisis por Técnicas de Rayos X; 2006
Institución organizadora:
Universidad de Tarapacá- Chile
The determination of trace elements to evaluate the air-pollution studies is very important. The samples are generally obtained by collecting the airborne dust particles on membrane filters. For quantification by TXRF, the samples can be digested by a strong acid or mixture of acids and heating. However, a rapid procedure for multi-element determinations of trace elements in great number of samples is needed. In this regard, different sample preparation procedure was compared. Until now the digestion acid method for sample preparation is one of the used ones in TXRF. Recently a thin-film sample procedure is described which requires minimal sample preparation, this involves first bringing the oil into solution with a volatile solvent. In this work different sample preparation procedure was compared. Monitoring campaigns was carried out in Temuco city and other cities by collecting the PM10 fraction and the total suspended particulates (TSP) of the airborne dust particles, entrapping element on polycarbonate filters. Each set comprised two polycarbonate membrane filters, one of which was 0.4 µm, and other 8 µm. Controls were unloaded filters each. The sample preparation was carried out by three procedures: a) digestion: this involves bringing the adsorbed elements into solution by a mixture of strong acids and heating; b) dissolution: this involves bringing the filter into solution with a volatile solvent; c) without treatment. After a and b treatments, micro liter amounts were pipetting on to the reflector substrate followed by evaporation of the solvent and the heavy metal concentration was determined by total reflection x-ray fluorescence (TXRF). The conventional X-ray fluorescence (XRF) analysis was used to the elemental measures on non-treated filters. In TXRF, quantification was carried out by internal standardization adding Rb to the samples and a separate calibration curve were set up with Rb. Accuracy of each sample preparation procedure was checks by analysis of reference material. Results by application of the different sample preparation procedures will be reported in this Seminary.