The preparation of the sample can be performed differently; each
method has its own advantages and limitations.
Samples with high
organic content such as biodiesel make the analysis through F AAS
difficult.
This problem could be solved by diluting it with a suitable
organic solvent, even though this action lowers the limit of detection
of the procedure [14].
Alternatively, the sample can be mineralized,
but this procedure is prone to contamination or analyte loss.
The
emulsification of the sample would be another possibility, but in this
case, problems can occur with the stability of the emulsion and
calibration [14].
The use of microemulsion as sample preparation is
applied for determining trace metals in biodiesel.
The microemulsions
are mechanically and thermodynamically stable, transparent or
translucent, homogeneous, and low-viscosity system.
They are
formed spontaneously by mixing two immiscible liquids, one of
them uniformly dispersed in the other as micro drops of a third
component, which can be a surfactant (detergent molecules) or a cosurfactant
(alcohol or amine molecules).
Great solubilization of
organic and inorganic substances is reached with this kind of
treatment