Twenty underivatized essential amino acids were separated using capillary zone electrophoresis and consequently detected with contactless conductivity detection (CCD). A simple acidic background electrolyte (BGE) containing 2.3 M acetic acid and 0.1% w/w hydroxyethylcellulose (HEC) allowed the electrophoretic separation and sensitive detection of all 20 essential amino acids in their underivatized cationic form. The addition of HEC to the BGE suppressed both, electroosmotic flow and analyte adsorption on the capillary surface resulting in an excellent migration time reproducibility and a very good analyte peak symmetry. Additionally, the HEC addition significantly reduced the noise and long-term fluctuations of the CCD baseline. The optimized electrophoretic separation method together with the CCD was proved to be a powerful technique for determination of amino acid profiles in various natural samples, like beer, yeast, urine, saliva, and herb extracts.

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The inclusion complex of catechin with cyclodextrins (CDxs) is examined by the use of l H NMR, UV, and circular dichroism spectroscopies. The UV measurements demonstrate the existence of additional absorbing species of catechin in the presence of P-CDx. The 'H NMR provides evidence for the formation of inclusional complexes between catechin and P-and y-CDxs through changes in the chemical shifts of the proton resonances of catechin and that of the protons inside the CDx activity. The apparent formation constant is estimated by use of circular dichroism.

The increased fluorescence intensity of pyrene due to indirect excitation by the nonionic surfactant Triton X-100 is discussed. Sensitization is quantitatively shown to occur in mixed solutions of pyrene, Triton X-100, and β-cyclodextrin (β-CD). A ternary complex is formed below the critical micelle concentration (CMC). Above the CMC, pyrene is displaced from the β-CD cavity. This is accompanied by a subsequent incorporation of pyrene into the interior of the micelle. Evidence is given that ternary complexation occurs among pyrene, CD, and TX-100.

The surfactants Igepal CA720 (IplCA7) and Triton X-102 (TX-102) and their interaction with β-cyclodextrin were studied with the use of various photophysical and photochemical methods. The fluorescence and absorbance spectra of these surfactants are concentration dependent and markedly enhanced in the presence of β-cyclodextrin. Nuclear magnetic resonance (NMR) spectroscopy infers that the phenyl group of these surfactants is included inside the β-CDx cavity. The orientation of the phenyl moiety of the surfactant molecule inside the β-CDx cavity was investigated with the use of induced circular dichroism (ICD).