A porphyrin‐based fluorescence method for zinc determination in commercial propolis extracts without sample pretreatment

Abstract

The quantification of zinc in over-the-counter drugs as commercial propolis extracts by molecular fluorescence technique using meso-tetrakis(4-carboxyphenyl)porphyrin (H TCPP ) was developed for the first time. The calibration curve is linear from 6.60 to 100 nmol L of Zn . The detection and quantification limits were 6.22 nmol L and 19.0 nmol L , respectively. The reproducibility and repeatability calculated as the percentage variation of slopes of seven calibration curves were 6.75% and 4.61%, respectively. Commercial propolis extract samples from four Brazilian states were analyzed and the results (0.329-0.797 mg/100 mL) obtained with this method are in good agreement with that obtained with the Atomic Absorption Spectroscopy (AAS) technique. The method is simple, fast, of low cost and allows the analysis of the samples without pretreatment. Moreover the major advantage is that Zn-porphyrin complex presents fluorescent characteristic promoting the selectivity and sensitivity of the method.

Photoactivatable Surface-Functionalized Diatom Microalgae for Colorectal Cancer Targeted Delivery and Enhanced Cytotoxicity of Anticancer Complexes

“…Indeed, the Soret band of the porphyrin undergoes a bathochromic shift from 415 to 423 nm upon reaction with Zn(OAc)2•2•H2O (Figure 3). Moreover, upon metalation, the degeneracy in the porphyrin orbital causes the coalescence of the four TCPP Q-bands (512, 546, 588 and 645 nm) into two Q-bands in B12-ZnTCPP (560 and 601 nm), as previously described [64,65]. The peaks at 360 nm and 517 nm were respectively attributed to the α-band and β-band of vitamin B12 (Figure 3).…”

Photoactivatable Surface-Functionalized Diatom Microalgae for Colorectal Cancer Targeted Delivery and Enhanced Cytotoxicity of Anticancer Complexes

“…Where is the absorbed light intensity from the sample, the light intensity from the light source and ( = 420 ) the absorbance of the photosensitizer at the excitation wavelength. two Q-bands in B12-ZnTCPP (560 and 601 nm) as previously described [62,63]. The peaks at 360 nm and 517 nm were respectively attributed to the α-band and β-band of vitamin B12 (Figure 2).…”

Photo- and radio-luminescence of porphyrin functionalized ZnO/SiO2nanoparticles

“…By exciting ZS-AP-Y samples in the TCPP Soret band (at 3.1 eV), only the dye PLs at about 1.7 eV and 1.9 eV are observed; moreover, in addition to the characteristic TCPP PL features, a peak centred at about 2.0 eV is detected, especially in the samples with the lowest dye loading (ZS-AP-0.1 and ZS-AP-0.25). This band can be associated with the presence of Zn-TCPP complexes, 62,63 whose formation is due to the partial release of zinc ions from the highly reactive surface of ZnO NPs and their subsequent coordination with the porphyrin ring. 59 An accurate discussion of data presented in Fig.…”