Porphyrin-based sensors

Detection of nitric oxide has become particularly important in light of its regulatory role in many physiological processes. In an example of NO detection via porphyrin-based sensors, Malinski and coworkers have used microelectrode sensors consisting of layers of a polymeric... 

The detection limit of the porphyrin-based sensors toward HBHA decreased as the pH increases, ranging from 0.3 mM at pH 5. to 0.65 mM at pH 9.0. However, at physiological pH 7.4 the detection limit (30 mM) was quite... 

Ciszewski, A., G. Milczarek, E. Kubaszewski, and M. Lozynski (1998). Oxidation of nitric oxide at a porphyrinic-based sensor. New results from rotating disk experiments. Electroanalysis 10(9), 628-632. 

Ishihara S, Labuta J, Van Rossom W, Ishikawa D, Minami K, Hill JP, Ariga K (2014) Porphyrin-based sensor nanoarchitectonics in diverse physical detection modes. Phys Chem Chem Phys 16(21) 9713-9746... 

Beheshti SS, Sohbat F, Amini MK (2010) A manganese porphyrin-based sensor for flow-injection potentiometric determination of thiocyanate. J Porph5uins Phthalocyanines 14 (02) 158-165... 

C.DiNatale, D.Salimbeni, R.Paolesse, A.Macagnano, A.D Amico. Porphyrins-based opto-electronic nose for volatile compounds detection, Sensors and Actuators B 65 (2000) 220-6. 

Fig. 10.43. Porphyrin-based fluorescent sensors of neutral molecules (P-1 Kijima H. et al. (1999) Chem. Commun. 2011. P-2 D Souza F. (1996) J. Am. Chem. Soc. 118, 923. P-3 D Souza F. (1997) Chem. Commun. 533).

The OLED-based sensors were tested in the 23-60°C temperature range. The values of t are expected to generally decrease with increasing temperature, as the PL quenching is enhanced at elevated temperatures [47]. However, in the 23-60°C studied range, the phosphorescence of porphyrins is only slightly dependent on the temperature [68]. Indeed, the temperature effect on the SV plots was minimal small reductions in tq and t (100% O2) were observed as the temperature increased, e.g., for one film, tq decreased from 91 to 84 js with Sg varying from 36.5 to 37.5. 

Another promising example of a metal-based sensor can be seen in the work of Lee and Okura (239) who used entrapped platinum octaethylporphyrin complexes to form photostable devices. In their study, they found by adding the surfactant Triton X-100 to the sol-gel mixture, they could improve homogeneity and phosphorescence of the dye-containing glass. Encapsulated porphyrin molecules have also been used successfully in the sensing of nitrogen dioxide (240) and, as will be discussed below, can be used to sense metal ions. 

It should be noted that 86 also functions as an electrochemical anion sensor, where the Zn(II) porphyrin-based oxidation potential is sensitive to... 

The most extensive efforts to develop the OLED-based sensor platform have focused on PE-based gas-phase and dissolved O2 (DO) sensors. Such sensors, which have been studied for many years, are based on the efficient quenching of the PL of dyes such as Ru complexes and Pt or Pd porphyrins by collisions with O2 molecules the sensitivity to O2 is due to the nearly unique triplet nature of the ground state of O2. In an ideal homogeneous matrix, the O2 concentration [O2I is related to the steady-state PL intensity I and the PL decay time x by the Stern-Volmer (SV) equation ... 

Fig. 5 Two examples of porphyrin-based cooperative optical sensors, (a) A ditopic receptor for binary metal salts. (h) A cyclodextrin-capped porphyrin system able to sense and report in four distinguishable association modes. ...

Studies of synthetic porphyrin-based anion receptors should form the basis for more effective sensors. Metallocene-substituted porphyrins examined by Beer and coworkers have proven successful in the solution-phase binding of ions such as chloride, bromide and nitrate." The cobaltocenium-substituted and ferrocene-substituted porphyrins (Figure 134) bind ions in solution, as shown by H NMR and electrochemical studies. The latter measurements reveal that the porphyrin and ferrocene redox... 

A. Preparation of Porphyrin-Based Potentiometric Sensors for Anions.252... 

Porphyrin-based electrochemical sensors possess a unique set of characteristics that may make them of fundamental importance in solving some of the problems in pure and applied biology and medicine. Sensor properties that are particularly advantageous are small size and fast response time, as well as the ability to provide both qualitative and quantitative information about an electroactive analyte. The main challenge in the development of a successful electrochemical sensor is the improvement of its selectivity. 

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