Evaluation of dried matrix spot sampling for total sulphur determination in automotive gasoline by high-resolution continuum source molecular absorption spectrometry and direct solid sample analysis.

In this work, a method for total sulphur determination in automotive gasoline using dried matrix spot sampling is proposed. The method is based on the deposition of the sample on a cellulose-based filter paper and subsequent sulphur quantification via CS diatomic molecule using high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS). The sample deposition was carried out, along with the chemical modifier, on a 20-mm filter paper disc previously adapted into a polytetrafluoroethylene (PTFE) mould.

The use of dried matrix spot for determination of Pb and Ni in automotive gasoline by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry.

In this work a simple and practical method for the determination of Pb and Ni in automotive gasoline by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry was investigated. In the proposed method, disks of filter paper were used to pre-concentrate and store Pb, Ni and other trace elements from automotive gasoline samples. For this, a volume of sample was deposited and dried out on a filter paper disk previously adapted into a polytetrafluoroethylene mold, and then the gasoline-embedded filter paper was either cut into small pieces or pulverised and introduced directly into the graphite furnace for trace element determination.

Evaluation of lead desorption from cement matrices.

Desorption of lead immobilized into cement and concrete matrices was evaluated in the pH range between 4 and 8 within a period of 2 h to 15 days. Lead-desorbed content in aqueous milieu was monitored by Graphite Furnace Atomic Absorption Spectroscopy, while matrices were directly analyzed by X-ray photoelectronic spectroscopy or Rutherford Backscattering spectrometry. For low pH, higher Pb desorption was observed, about 5-7 times higher than that measured in the case of concrete matrices.