Suitability of three-dimensional synchronous fluorescence spectroscopy for fingerprint analysis of honey samples with reference to their phenolic profiles.

The suitability of a right-angle geometry three-dimensional synchronous fluorescence spectroscopy (3D-SFS) for the differentiation and classification of different honey types, including acacia, buckwheat, heather, linden, multiflower and rape honeys, was evaluated with reference to their phenolic profiles. The fraction of phenolic compounds was initially isolated and pre-concentrated from analyzed samples by means of polymeric reversed phase Strata X solid phase extraction (SPE) cartridges. A thoughtful analysis of 3D-SF spectra of resulting methanolic extracts of honey samples containing the separated fraction of phenolics and standards of phenolic acids and flavonoids revealed that the proposed methodology based on SPE and 3D-SFS is capable of discriminating honey samples due to different floral sources in a fast and straightforward way.

The action of photosensitizers and serum in a bactericidal process. II. The effects of dyes: hypericin, eosin Y and saphranine O.

The aim of the present work was to recognize the reasons for differences in the photodynamic action of dyes against various bacterial strains. It is expected that a better understanding of this problem may help in design of new photosensitizers. The sensitivity of 6 various bacterial strains to the photodynamic action of 5 photosensitizers was determined. The hydrophobicity of cell surface and susceptibility of bacteria to the natural defense mechanism of human serum, were estimated. The differences in the photodynamic efficiency of dyes could be contributed to various affinities of cell membrane to dyes, to known details of membrane architecture as well as to different mechanisms of photosensitization.

Proton translocation in monomolecular Langmuir-Blodgett films including 2-naphthol and 1,4-anthraquinone derivatives.

The scope of the present work is the investigation of proton transport through monomolecular Langmuir-Blodgett (LB) films. The films were formed from amphiphilic molecules: 2-naphtholo-6-sulfonamide of dodecylamine (N) and 1,4-anthraquinono-2 sulfonamide of dodecylamine (A). The 2-naphthol derivative can act as a proton donor due to excited state proton transfer (ESPT) and the 1,4-anthraquinone group can play the role of proton acceptor because of protonation of the reduced form if it is present. Absorption and emission spectra of LB films containing N and A were registered and separated into component bands. Individual absorption and emission peaks observed were assigned to given forms of chromophores. The behavior of different component bands reflects the state of anthraquinone dependent on proton concentration. A correlation of rate and efficiency of ESPT, with changes of the spectra of A, may be expected to yield information concerning the transport of protons from N to A. The influence of the donor-acceptor distance, sample humidity, film arrangement and the presence of protonophores (Gramicidin A) on proton transfer is studied. Our results indicate that the proton can be transported through the film but its concentration vanishes at the distance greater than 30 A. The efficiency of proton transfer depends strongly on water content, film structure and the presence of ion channels.

Synergistic action of photosensitizers and normal human serum in a bactericidal process. I. Effect of chlorophylls.

Susceptibility of some Gram-negative strains against the bactericidal action of normal human serum (NHS) and of chlorophyll, which induces production of reactive oxygen species by light, was studied. A synergistic bactericidal activity of NHS and chlorophyll against E. coli K1 and Shigella flexneri strains was observed.