The chromatographic retention of a number of phenols on Diasphere-110-C18 sorbent modified with a zinc octa-4,5-carboxyphthalocyanine was studied. It was examined whether the Scott-Kucera and Snyder-Soczewinski displacement models of retention could describe the experimental data obtained. Both the models proved to be adequate in describing the experimental data at contents of the polar component in the mobile phase of 8–70%. The phenols were found to be eluted in order of increasing hydrophobicity.

The adsorption of water-soluble vitamins on the surface of Diaspher-110-C 18 sorbent modified with zinc octa-4,5-carboxyphthalocyanate is studied. Adsorption isotherms are constructed and calculated by the Glücauf method at 20°C. It is established that the shape of the isotherms depends on the nature of vitamins and their structure: the isotherm of vitamin C is a Henry-type isotherm, the isotherms of vitamins B 3 and B 6 are of S-type, and the isotherm of vitamin PP-amide is of L-type. Monolayer capacities, adsorption equilibrium constants, and Gibbs energy changes are calculated.

As evidenced by ion-selective electrode potentiometry, the hexameric R-phycoerythrin (RPE) molecule binds 20–4000 cadmium ions (Cd2+) depending on Cd2+ concentration in the solution. Cadmium ions bound to RPE serve as the nuclei of cadmium sulfide crystallization in the presence of sulfide ions. According to spectrometric, electron-microscopic, and capillary electrophoresis data, the particles are heteroaggregates of 3.2 × 6 nm in size. The fact that the particle size fits the size of the central tunnel of the RPE molecule and the similarity between the electrophoretic patterns of free RPE and the RPE-CdS complex indicate that the tunnel space, limiting the crystal growth, is the most probable site of nanoparticle formation. Properties of the nanoparticles can be modified by changing temperature, pH, etc. It is concluded that RPE can be used as a reagent for detoxification of cadmium ions and a matrix for synthesis of elongated CdS nanoparticles.

The adsorption of the zinc octa-4,5-carboxyphthalocyanate modifier on known HPLC sorbents of different types (Silasorb-C18, Diasorb-130-C4, Diasorb-130-C16, Spheron C 100 (LC), Spheron C 1000, and Hema S 1000 QL) was studied. The optimum conditions were determined for the modification of the sorbents in the static and dynamic modes. The mechanism of the retention of modifiers and adsorbates was considered, and the amount of the modifier on the surface of the adsorbents was calculated. The effect of the modifier on the retention of adsorbates was demonstrated. Mobile phases were selected for the selective and efficient separation of model mixtures of phenols.

The chromatographic retention of some hemin-based peptides on the Diasphere-110-C18 sorbent modified with zinc octa-4,5-carboxyphthalocyaninate was studied. It was demonstrated that this stationary phase is more selective for hemin-peptides than Nucleosil-C18 and Silasorb-600. The conditions of the separation of mixtures of hemin-based peptides were determined, and the parameters of their chromatographic separation were calculated. It was shown that the retention parameters are related to the structure of hemin-based peptides.

The behavior of vitamins E and D3 was studied under the conditions of reversed-phase high-performance liquid chromatography with the use of unmodified and modified mobile phases. Acetonitrile modified with chlorophyll (a + b) (Chl) and tetraphenylporfyrin (H2TPP) was selected for the indirect spectrophotometric detection of vitamins. It was demonstrated that detection limits are 2.3 μg (8.33 × 10–6 M H2TPP, λ= 404 nm) and 3.5 ng (8.6 × 10–6 M Chl, λ = 430 nm) for vitamin E and 0.12 μg (3.0 × 10–7 M H2TPP, λ = 420 nm) for vitamin D3 . Pharmaceutical preparations containing vitamins E and D3 were analyzed.

The chromatographic behavior of meso-tetrahexylporphyrin and its complexes with Zn(II) and Pd(II) was studied using a reversed-phase microcolumn. Adsorption isotherms were calculated for the acetonitrile-ethyl acetate (60 : 40)-Nucleosil C-18 system. The adsorption isotherms obtained were found to be S-shaped.

The chromatographic behaviour of some porphyrins and their complexes with zinc has been studied by HPLC on 150×3.9 mm and 300×3.9 mm columns packed with Nova-Pak C18 and μ-Bondapak C18, respectively, and on a microcolumn (64×2 mm) packed with Nucleosil C18. The effect of the nature and the arrangement of side substituents in the porphyrin molecules on retention is considered. It is demonstrated that HPLC can be used for the separation ofcis-andtrans-isomers (atropisomers) of the zinc complex of 5,15-di(phenyl-2-CH3O)-3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrin and other porphyrins with a similar structure. The efficiency of separation has been compared on different columns.

The adsorption of octa-4,5-carboxyphtharocyanine and its complexes with zinc, copper, cobalt(II), lead, and vanadyl from aqueous-organic solutions by a reversed-phase sorbent was studied under static conditions. Adsorption isotherms were constructed for the following solvents: dimethyl formamide-water (30 : 70) and dimethyl sulfoxide-water (30 : 70 and 50 : 50). The isotherms of adsorption of phthalocyanine and metal phthalocyanines were constructed. It was shown that the adsorption value is determined by the interaction of the solvent with the central metal ion. The values of the limiting monolayer adsorption, the Langmuir adsorption equilibrium constant, and the Gibbs free energy change were estimated.

The chromatographic behavior of tetra-4-tert-butylphthalocynine; its 1 : 1 complexes of Zn(II), Cu(II), Mg(II), Ni(II), Pd(II), Co(II), Rh(III), and Sn(IV); 1 : 2 complexes of Lu(III), Dy(III), and Tb(III); and a linear dimer of copper hexa-4-tert-butyldiphthalocyanine were studied on hydrophobized, aminated, and unmodified silica gels. The retention of the above complexes was studied as a function on the composition of the mobile phase, the nature of the metal atom, the number of macrocycles in the ligand, and the length of the chromatographic column. It was shown that hydrophobized silica gels with acetone, acetonitrile–acetate (1 : 1), methanol–ethyl acetate (1 : 1), and dimethylformamide mobile phases are the most selective systems for determining the purity of the phthalocyanines. For each compound, an individual, usually symmetrical peak was observed. The parameters of these peaks can be used for the rapid identification and sensitive determination of the compounds studied. The detection limits were at a level of n× 10–8M.

The retention characteristics of tetraphenylporphyrin and a number of its derivatives on Silasorb 600, Nucleocil C-18, Diasorb-130-phenyl, and Diasorb-130-amine sorbents are studied and compared under conditions of normal and reversed-phase high-performance liquid chromatography. The applicability of some models of retention to these systems is considered. It is shown that the polarity of the substituents, the solubility of the compounds, solvation processes, and porphyrin-adsorbent-eluent interactions affect the retention characteristics.

In this work the influence of the porphyrin structure and of the nature of the mobile phase upon retention parameters is examined by means of reversed phase high-performance liquid chromatography (HPLC). Acetonitrile–ethyl acetate and other mixtures were used as eluents. An increase in the retention of azo- and benzosubstituted porphyrins as well as of those containing a large number of carbon atoms as substituents of macrocycles may be noted. A variation in the polarity of the mobile phase affects the retention of the ligands more than that of their zinc complexes. The retention of the most hydrophobic compounds may be well described in coordinates lg k'– lg M. For less hydrophobic porphyrins these dependences are close to linear only within limited intervals of mobile phase ethyl acetate concentration. The best separation of zinc complexes was achieved with acetonitrile as the eluent. The detection limit of porphyrin ligands and complexes with metals is n × 10-8 M.

Octadecylsulfamoyl and tert-butyl derivatives of phthalocyanine were studied as mobile-phase modifiers for the indirect detection of fullerenes. It was demonstrated that the sensitivity of determining fullerenes with indirect spectrophotometric detection at 669 nm depends on the nature of the modifier, its concentration in the mobile phase, and the temperature of the column. When the terta-4-tert-butylphthalocyanine complex of zinc was used as the modifier of the ethyl acetate-acetonitrile (9 : 1) mobile phase, the sensitivity of determining C-60 was twice as high as for the direct detection (368 nm). The chromatograms (669 nm) of benzene extracts of graphite black give an estimate of the actual ratio between fullerenes and products of their synthesis and can be used for the rapid determination of the ratio and concentrations of C-60 and C-70 fullerenes in samples.

The chromatographic behavior of tetraphenylporphyrin and some of its derivatives have been investigated by normal- and reversed-phase high-performance liquid chromatography to investigate the mechanisms of retention of porphyrins. The results obtained show that the polarity of the phenyl substituents, the solubility and solvation of the porphyrins, the nature of the central metal atom, and the nature and composition of the mobile phase affect the chromatographic behavior and adsorption of tetraphenylporphyrin derivatives.