APPLICATION OF VARIABLE-ANGLE SYNCHRONOUS PHOSPHORIMETRY IN A MICROEMULSION MEDIUM FOR THE SIMULTANEOUS DETERMINATION OF 3 POLYAROMATIC HYDROCARBONS

The applicability of variable-angle synchronous scanning (VASS) phosph orimetry at room temperature has been demonstrated, for the first time , for the simultaneous determination of the polycyclic aromatic hydroc arbons phenanthrene, fluoranthene and benz[a]anthracene. This techniqu e permits linear or non-linear paths to be scanned at preselected angl es through the excitation-emission phosphorescence matrix in order to obtain the highest signal values and interference-free bands. The phos phorescence emissions of the three compounds have been obtained using microemulsion aqueous solutions in an apolar solvent. In order to obta in the optimum spectrophosphorimetric responses, a statistical model o f central composite design type was applied. The increased selectivity afforded by the VASS technique has permitted the simultaneous determi nation 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%.