Selective and sensitive in vitro detection method for aluminum phthalocyanine photosensitizers, using liquid chromatography and diode-laser induced fluorescence
التفاصيل البيبلوغرافية
العنوان:
Selective and sensitive in vitro detection method for aluminum phthalocyanine photosensitizers, using liquid chromatography and diode-laser induced fluorescence
A combination of conventional-size liquid chromatography (LC) and visible diode-laser induced fluorescence (DIO-LIF) detection has been applied for the detection of photosensitizers used in photodynamic therapy. Of these photosensitizers, a mixture of disulfonated aluminum phthalocyanines (AlPcS 2 ) has been chosen as a model. First, the influence of pH and solvent on the spectroscopic properties of di- and tetrasulfonated aluminum phthalocyanine has been examined, indicating the presence of multi-step ionization equilibria and the formation of aggregates. Direct fluorescence detection of AlPcS 2 is found to be unsatisfactory. For biological samples, the introduction of LC showed clear advantages, especially for faeces extracts. A detection limit of 7 × 10 −12 M was found for AlPcS 2 ( S/N = 3 for the major component) in both rat urine and faeces extracts using the DIO-LIF system, which is 20-fold more sensitive than a conventional fluorescence detection system, in combination with chromatography.