Recent progress in adsorbed stationary phases for capillary electrochromatography

This review surveys the recent progress in the adsorbed stationary phases for capillary electrochromatography (CEC). Adsorption-based methods for preparation of stationary phase are novel approaches in CEC, which allow rapid and facile preparing stationary phases with desirable selectivity onto an open-tubular fused-silica capillary, a baresilica or ion-exchange packed column or a monolithic silica or polymer column. A variety of adsorbing agents have been developed as adsorbed stationary phases, including ionic long-chain surfactant, protein, peptide, amino acid, charged cyclodextrin (CD), basic compound, aliphatic ionene, and ion-exchange latex particle. The adsorbed stationary phases have been applied to separation of neutral, basic and acidic organic compounds, inorganic anions and enantiomers. They have also been applied to on-line sample concentration, fast separation and study of the competitive binding of enantiomers with protein.

Iron and inorganic carbon in Liaodong Gulf sediments of Bohai Sea in China

Iron in seawater is an essential trace metal for phytoplankton that plays an important role in the marine carbon cycle. But most studies focused on oceanic iron fertilization in high nutrient low chlorophyll (HNLC) seawaters. A study of inorganic carbon (IC) forms and its influencing factors was presented in Liaodong Gulf sediments, and especially the influence of iron was discussed in detail. Inorganic carbon in Liaodong Gulf sediments was divided into five forms: NaCl, NH3·H2O, NaOH, NH2OH·HCl and HCl. The concentration of NaCl and NaOH forms were similar and they only occupied the minority of total inorganic carbon (TIC). However, NH3·H2O, NH2OH·HCl and HCl forms were the principal forms of TIC and accounted for more than 80% of TIC. Especially, the percentage of NH3·H2O form was much higher than that in the Changjiang River Estuary and Jiaozhou Bay sediments. All forms of inorganic carbon were influenced by organic carbon,pore water, iron, pH, redox potential(Eh) and sulfur potential(Es) in sediments, moreover, the influences had different characteristics for different IC forms. However, the redox reactions of iron affected mainly active IC forms. Iron had little effect on NH2OH·HCl and HCl forms of IC which were influenced mainly by pH. Iron had a stronger influence on NaCl, NaOH and NH3·H2O forms of IC; the influence of Fe2+ was higher than Fe3+ and its effect on NH3·H2O form was stronger than on NaCl and NaOH forms.

UV-photooxidation as pretreatment step in inorganic analysis of environmental samples

Many laboratories deal with the determination of heavy metals, carbon, nitrogen and phosphorus. The first step in chemical analysis is a proper preparation of the investigated samples. The presence of organic substances can cause problems in many analytical methods. This paper describes the application of UV irradiation as a method of destruction of organic matter in the investigated samples.

Effects of temperature, glucose and inorganic nitrogen inputs on carbon mineralization in a Tibetan alpine meadow soil

High levels of available nitrogen (N) and carbon (C) have the potential to increase soil N and C mineralization We hypothesized that with an external labile C or N supply alpine meadow soil will have a significantly higher C mineralization potential and that temperature sensitivity of C mineralization will increase To test the hypotheses an incubation experiment was conducted with two doses of N or C supply at temperature of 5 15 and 25 C Results showed external N supply had no significant effect on CO2 emission However external C supply increased CO2 emission Temperature coefficient (Q(10)) ranged from 113 to 1 29 Significantly higher values were measured with C than with N addition and control treatment Temperature dependence of C mineralization was well-represented by exponential functions Under the control CO2 efflux rate was 425 g CO2-Cm-2 year(-1) comparable to the in situ measurement of 422 g CO2-Cm-2 year(-1) We demonstrated if N is disregarded microbial decomposition is primarily limited by lack of labile C It is predicted that labile C supply would further increase CO2 efflux from the alpine meadow soil (C) 2010 Elsevier Masson SAS All rights reserved

Model analysis of dissolved inorganic phosphorus exports from the Yangtze river to the estuary

In this paper, we estimate the inputs of phosphorus (P) to the Yangtze River Basin and exports of dissolved inorganic phosphorus (DIP) from the river to the estuary for the period 1970-2003, by using the global NEWS-DIP model. Modeled DIP yields range from 2.5 kg P km(-2) yr(-1) in 1970 to 4.6 kg P km(-2) yr(-1) in 1985, and then dramatically increase to 14.1 kg P km(-2) yr(-1) in 2003. No significant difference between the modeled and measured values at the level of P = 0.05 is observed. The study also demonstrates variable source contributions of P to the modeled DIP during the period 1970-2003. Point sewage P input accounted for approximately 100% in the period 1970-1985 and substantially decreased to 24.8% in 2003. Chemical fertilizer contributed 25.4% of DIP yields in 1986 and increased continuously to 50.3% in 2003, while a stable trend in manure P contribution averaging 22.9% of DIP yields was shown in the same period. The study concludes that P inputs to the Yangtze River Basin and the river DIP export to the estuary have substantially increased during the study period consequence to human pressure.

Synthesis and luminescence properties of hybrid organic-inorganic transparent titania thin film activated by in-situ formed lanthanide complexes

Stable transparent titania thin films were fabricated at room temperature by combining thenoyltrifluoroacetone (TTFA)-modified titanium precursors with amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO, P123) copolymers. The obtained transparent titania thin films were systematically investigated by IR spectroscopy, PL emission and excitation spectroscopy and transmission electron microscopy. IR spectroscopy indicates that TTFA coordinates the titanium center during the process of hydrolysis and condensation. Luminescence spectroscopy confirms the in-situ formation of lanthanide complexes in the transparent titania thin film.

Synthesis, Reactivity, and Characterization of Sodium and Rare-Earth Metal Complexes Bearing a Dianionic N-Aryloxo-Functionalized -Ketoiminate Ligand

The synthesis and reactivity of a series of sodium and rare-earth metal complexes stabilized by a dianionic N-aryloxo-functionalized beta-ketoiminate ligand were presented. The reaction of acetylacetone with 1 equiv of 2-amino-4-methylphenol in absolute ethanol gave the compound 4-(2-hydroxy-5-methylphenyl)imino-2-pentanone (LH2, 1) in high yield.