Application of variable-angle synchronous phosphorimetry in a microemulsion medium for the simultaneous determination of three polyaromatic hydrocarbons

The applicability of variable-angle synchronous scanning (VASS) phosphorimetry at room temperature has been demonstrated, for the first time, for the simultaneous determination of the polycyclic aromatic hydrocarbons phenanthrene, fluoranthene and benz[a]anthracene. This technique permits linear or non-linear paths to be scanned at preselected angles through the excitation-emission phosphorescence matrix in order to obtain the highest signal values and interference-free bands. The phosphorescence emissions of the three compounds have been obtained using microemulsion aqueous solutions in an apolar solvent. In order to obtain the optimum spectrophosphorimetric responses, a statistical model of central composite design type was applied. The increased selectivity afforded by the VASS technique has permitted the simultaneous determination of the three phosphorescent compounds with closely overlapping profiles added to coffee samples giving mean recoveries of 94% with a relative standard deviation of 1.5%.