Mono and co-immobilization of imidazolium ionic liquids on silica: effects of the substituted groups on the adsorption behavior of 2,4-dinitrophenol.

Ionic liquid modified silicas with high adsorption capacity for phenols prompt us to deeply explore the contribution of interactions between the adsorbent and adsorbate, with a particular focus on hydrophobicity, π-π, electrostatic and acid-base interactions. Herein, by introducing a series of typical substituent groups including ,-dimethylaminopropyl (A), benzyl (B), dodecyl (D) and naphthylmethyl (N) in an imidazole ring (Im), three mono-immobilized and two co-immobilized imidazolium ionic liquid modified silicas, namely SilprAImCl, SilprBImCl, SilprNImCl, SilprDBImCl and SilprDAImCl, werre synthesized for removal and recovery of 2,4-dinitrophenol (2,4-DNP) from aqueous solutions. Adsorption kinetics, isotherms, thermodynamic analysis and desorption experiments have been carried out.

Fabrication of cefotaxime sodium-functionalized gold nanoclusters for the detection of copper ions in Chinese herbal medicines.

Antibiotic-based gold nanoclusters (AuNCs) are a good sensing platform for specific recognition; however, the related studies are few. Herein, a simple and facile strategy was proposed for the fabrication of bright blue fluorescent AuNCs through the degradation product (DCTX) of cefotaxime sodium that induced the reduction of HAuCl. Various analytical techniques were applied to characterize the prepared AuNCs@DCTX.

Investigation of 1-Dodecylimidazolium Modified Filter Papers as a Thin-Film Microextraction Phase for the Preconcentration of Bisphenol A from Plant Oil Samples.

Based on the tunability of ionic liquids (ILs) according to the specific requirement of an application, 1-dodecylimidazolium chloride with amphiphilic structures was chemically fabricated on the surface of filter papers (DIL-FPs) for the first time. After synthesis, DIL-FPs was characterized by scanning electronic microscopy, energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. DIL-FPs was used as a novel thin-film microextraction (TFME) phase for the preconcentration of amphiphilic bisphenol A from plant oil samples.

Comparison and evaluation of five types of imidazole-modified silica adsorbents for the removal of 2,4-dinitrophenol from water samples with the methyl group at different positions of imidazolium ring.

The objective of this work was to improve the understanding the influence of the methyl group at different positions of imidazolium ring on the adsorption behaviors of imidazole-modified silica adsorbents. Five adsorbents named as SilprImCl, SilprM₁ImCl, SilprM₂ImCl, SilprM₄ImCl and SilprM₁M₂ImCl were synthesized using imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole and 1,2-dimethylimidazole, respectively. These adsorbents were characterized by scanning electron microscope, infrared spectra, thermogravimetric analysis, elemental analysis and BET analysis.

Recovery of nickel from aqueous samples with water-soluble carboxyl methyl cellulose-acetone system.

A simple and efficient method, which involves carboxyl methyl cellulose (CMC) and acetone, was developed for recovery of trace nickel from aqueous solutions. This method was based on the fact that Ni2+ could react with CMC and form water-soluble complexes, which would solidify in excess acetone. After centrifugation, the solid mass consisting of the nickel complex and free CMC was easily dissolved with water and the nickel was determined by flame atomic absorption spectrometry (FAAS).

Headspace liquid-phase microextraction using ionic liquid as extractant for the preconcentration of dichlorodiphenyltrichloroethane and its metabolites at trace levels in water samples.

A novel technique, high temperature headspace liquid-phase microextraction (HS-LPME) with room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) as extractant, was developed for the analysis of dichlorodiphenyltrichloroethane (p,p'-DDT and o,p'-DDT) and its metabolites including 4,4'-dichlorodiphenyldichloroethylene (p,p'-DDE) and 4,4'-dichlorodiphenyldichloroethane (p,p'-DDD) in water samples by high performance liquid chromatography with ultraviolet detection. The parameters such as salt content, sample pH and temperature, stirring rate, extraction time, microdrop volume, and sample volume, were found to have significant influence on the HS-LPME. The conditions optimized for extraction of target compounds were as follows: 35% NaCl (w/v), neutral pH condition, 70 degrees C, 800 rpm, 30 min, 10 microL [C4MIM][PF6], and 25 mL sample solutions.

Preparation of the diphenylcarbazone-functionalized silica gel and its application to on-line selective solid-phase extraction and determination of mercury by flow-injection spectrophotometry.

A new solid-phase extractor, diphenylcarbazone-functionalized silica gel has been synthesized and confirmed by IR and Raman spectrometry. The new solid-phase extractor is found to be stable in 1-6 mol L(-1) HCl or H(2)SO(4), and also in common organic solvents. It can be used to separate and enrich Hg(II) selectively from eight metal ions with similar characteristics such as Cd(II), Ni(II), Co(II), Mn(II), Pb(II), Zn(II), Cu(II) and Fe(III).

Determination of phenols in environmental water samples by ionic liquid-based headspace liquid-phase microextraction coupled with high-performance liquid chromatography.

Headspace liquid-phase microextraction (HS-LPME) has been applied to efficient enrichment of phenols such as 2-nitrophenol, 4-chlorophenol, 2,4-dichlorophenol, and 2-naphthol from water samples based on 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) as an extractant. Some parameters that may influence HS-LPME were investigated. The linear range was in the range of 0.

Improved single-drop microextraction for high sensitive analysis.

This paper described a simple approach to prepare a small bell-mouthed extraction device for single-drop microextraction (SDME). Analytical sensitivity was improved by increasing the suspended acceptor volume. Because of the increased contact area and the rough inner surface of the extraction device, the stability of drop was markedly increased.

[Highly sensitive fluorescent reaction of acridine red with chromium (VI) and its application].

A simple and highly sensitive fluorimetric method for the determination of Cr(VI) was developed in the present paper. The method is based on the fluorescence enhancement of acridine red with Cr(VI) in the sulfuric acid medium. The effects of some experimental conditions on the determination of Cr(VI) were investigated in detail.

[Speciation analysis of selenium by flow-injection catalytic spectrophotometry].

A new flow-injection catalytic spectrophotometric method was proposed for the determination of Se(IV) based on its catalytic effect on the reduction reaction of azure I by Na2S in pH 7.0 citric-acid sodium-hydrogen-phosphate buffer solution. Some different schematic diagrams of FIA were compared.

Flow-injection spectrophotometric determination of sulfadiazine and sulfamethoxazole in pharmaceuticals and urine.

A rapid and sensitive flow-injection spectrophotometric method is proposed for the determination of sulfadiazine and sulfamethoxazole. This method is based on the diazotization of sulfonamide with sodium nitrite, and a coupling reaction of the diazo-compound with alpha-naphthylamine. The optimum experimental conditions are obtained by using the controlled and weighted centroid simplex method.