Simultaneous determination of meso-tetraphenylporphyrine and Co(II)-meso-tetraphenylporphyrine by high performance liquid chromatography with diode array detection and electrospray ionization mass spectrometry

A high performance liquid chromatography diode array detector-electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS) method without sample pretreatment was developed and validated for the determination of 5,10,15,20-mesotetraphenylporphyrine (TPP) and Co(II)-5,10,15,20-meso- tetraphenylporphyrine (CoTPP) in the catalyst. Samples were dissolved in CH2Cl2 and were directly injected into the HPLC-DAD-ESI-MS system in which an isocratic elution program was applied. The mobile phase was methanol-acetonitrile-chloroform (70:30:10, v/v). The mass spectrometer was operated in ESI monitoring mode. TPP and CoTPP were detected with excellent sensitivity and selectivity. The use of UV-Vis diode array allowed the detection of the analytes within the 0.5-15.4 mu g/mL range for TPP and 0.8-20.6 mu g/mL range for CoTPP. The lower limits of quantification were 0.076 mu g/ml for TPP and 0.32 mu g/ml for CoTPP. The results pointed out that the method was suitable for the catalyst and allowed their identification and quantification with no need for purification steps.