Key WordsColumn liquid chromatography Amino acids and oligopeptides Fluorescence derivatization N-hydroxysuccinimidyl-c~-(9-phenanthrene)-acetate
SummaryA sensitive LC method for the detection of amino acids and oligopeptides with pre-column fluorescence derivatization has been developed. Glycine, glycylglycine, triglycine, glutathione, glutamic acid, and cysteine were separated on a reversed-phase C18 column with methanol-water-triethylamine eluent, derivatization and chromatographic conditions were optimized. The six derivatives were eluted in 20 min with good reproducibility. The relative standard deviations (n --6) at an analytical concentration of 2 x 10 .6 M are < 5 %. Detection limits (signal-to-noise ratio = 3) for the six derivatives are 23-68 fmol.
In this paper, two fly ash samples from a popular of circulating fluidized bed (CFB) incinerators operated in spring and winter were detected. The organic pollutants of PAHs and Dioxins were 8.647 mg/kg and 778.859 pgI-TEQ/g respectively for the sample in spring, 11.008 mg/kg and 888.318 pgI-TEQ/g for the sample in winter. The distribution of Dioxins was analyzed, 2,3,4,7,8-PeCDF,2,3,7,8-TCDF and 2,3,7,8-TCDD were found to gave the great contribution to the total I-TEQ.
Based on X-ray diffraction results, the gallery height of modified Mg3Al-LDH was expanded to 9.6Å from the original 4.8Å, indicating that the H3PW12O40 was indeed inserted into the hydroxide layers. Moreover, the results of FT-IR spectra proved the Keggin structure of PW11O397- species. The resulting material showed a high activity of degradation of methyl orange in the presence of H2O2 and UV light irradiation.
Zn-Al hydrotalcite exhibited fluorescence property without fluorescent substances intercalation. Its maximum excitation wavelength was 406nm and maximum emission wavelength was 523nm. In this study citric acid and adipic acid were introduced into the interlayer of LDH, which enlarged the interlayer spacing. It was found that the fluorescence property was influenced by anions in the interlayer of hydrotalcites. And it would be favorable to bind with other organic compounds to get photocatalysis materials for citric acid modified Zn-Al hydrotalcite. Meanwhile, the fluorescence intensity was enhanced greatly after modified by adipic acid, so it could be used as photocatalyst precursors.
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