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The inclusion of dulcin in alpha- and beta-cyclodextrin has been studied by fluorescence spectroscopy. To quantitatively describe complex formation between the beta-cyclodextrin and dulcin, an association constant of 290 M(-1) at 21 degrees was obtained. The thermodynamics associated with the complex formation between dulcin and beta-cyclodextrin in aqueous solution has been studied. The obtained value of DeltaG(0) = -13.7 kJ/mole at 21 degrees , together with DeltaH(0) = -33.6 +/- 2.3 kJ/mole and DeltaS(0) = -67.2 +/-8.3 Jmole(-1) K(-1) indicate that dulcin has a very marked tendency to associate with beta-cyclodextrin in water. The inclusion complex of dulcin in beta-cyclodextrin has been used to determine dulein in the range 0.13-5 mug/ml the method has been applied to determine dulcin in soft drinks. 相似文献
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Garrido Frenich A Romero-González R Martínez Vidal JL Martínez Ocaña R Baquero Feria P 《Analytical and bioanalytical chemistry》2011,399(6):2043-2059
This work compares two miniaturised sample preparation methods, solid phase microextraction (SPME) and hollow fiber liquid
phase microextraction (HF-LPME), in combination with gas chromatography coupled to tandem mass spectrometry with a triple
quadrupole analyzer for the determination of 77 pesticides in drinking water. In the case of SPME, extraction temperature
and time were optimized by experimental design, although other parameters, as desorption time, pH, and ionic strength, were
also evaluated. The extraction and desorption solvents [octanol/dihexyl ether (75:25, v/v) and cyclohexane, respectively],
as well as the extraction and desorption time, ionic strength, and pH, were studied for the HF-LPME procedure. Under the optimal
conditions, recoveries (70.2–113.5% for SPME and 70.0–119.5% for HF-LPME), intra-day precision (2.1–19.4% for SPME and 4.3–22.5%
for HF-LPME), inter-day precision (5.2–21.5% for SPME and 8.4–27.3% for HF-LPME), and limits of detection, between 0.1 and
28.8 ng/L for SPME and 0.2 and 47.1 ng/L for HF-LPME and overall uncertainty (9.6–25.2% for SPME and 13.3–27.5% for HF-LPME)
were established for both extraction procedures. Finally, the proposed methods were successfully applied to the analysis of
41 drinking water samples, and similar results were obtained with both extraction approaches. 相似文献
3.
Dr. Kumudu Mudiyanselage Dr. Sanjaya D. Senanayake Dr. Leticia Feria Dr. Shankhamala Kundu Dr. Ashleigh E. Baber Dr. Jesús Graciani Dr. Alba B. Vidal Dr. Stefano Agnoli Prof. Jaime Evans Dr. Rui Chang Dr. Stephanus Axnanda Dr. Zhi Liu Prof. Javier F. Sanz Dr. Ping Liu Dr. José A. Rodriguez Dr. Darío J. Stacchiola 《Angewandte Chemie (International ed. in English)》2013,52(19):5101-5105
4.
Using instrumental neutron activation analysis (INAA), graphite furnace atomic absorption spectrometry (GFAAS), flame atomic absorption spectrometry (FAAS) and combustion elemental analysis, green coffees of the Arabica species produced in crop year 1987/88 in Colombia, Costa Rica, Cuba, El Salvador, Mexico, Nicaragua, Panamá and Papua New Guinea were analysed for the elements Ba, Br, C, Ca, Co, Cr, Cu, Cs, Fe, H, K, La, Mg, Mn, N, Na, Rb, Sc, Sr and Zn. In accordance with the concentrations determined, the elements could be ranked into five groups: Sc (sub-ppb level); Br, Co, Cr, Cs and La (ppb level); Ba, Cu, Fe, Mn, Na, Rb, Sr and Zn (ppm level); Ca and Mg (%o level); and C, H, K and N (% level). On the basis of the results obtained, an attempt was made to establish the origin of the green coffee via its elemental composition. Among the investigated elements, manganese was found to be best suited as an indicator for this purpose. However, the elements C, Co, Cs, Na and Rb proved to be of interest too. 相似文献
5.
Rangel-Peña Uriel J. Camacho-Mendoza Rosa L. González‐Montiel Simplicio Feria Leticia Cruz-Borbolla Julián 《Journal of Cluster Science》2021,32(5):1155-1173
The present study examines bonding patterns between copper Cun clusters (n?=?3–20) and aromatic compounds (benzene, phenol, and benzaldehyde) using a density-functional theory (DFT) approach. Hirshfeld population, natural bond orbital (NBO), molecular orbitals, and quantum theory of atoms in molecules (QTAIM) analyses suggested the formation of two types of interactions Cu–arene and C–H···Cu, in the complexation of copper clusters by an aromatic compound.
相似文献6.
I. C. Lawas A. del Callar J. A. Feria 《Journal of Radioanalytical and Nuclear Chemistry》1973,13(1):75-86
Human vesical, urethral and renal stones were analyzed for the trace elements Co, Cu, Mn, Zn and Mo. Statistical correlations
between the elements determined were sought which would be of possible interest in further research on the initial causes
of urinary stone formation in the human body.
This research project was funded by a grant from the National Research Council of the Philippines.
Read at the 40th Annual Convention of the Philippine Medical Association held in Manila, May 9, 1947. 相似文献
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