Eluent Selection Research Articles

Occurrence, toxicity and adsorptive removal of the chloramphenicol antibiotic in water: a review.

Chloramphenicol is a broad-spectrum bacterial antibiotic used against conjunctivitis, meningitis, plague, cholera, and typhoid fever. As a consequence, chloramphenicol ends up polluting the aquatic environment, wastewater treatment plants, and hospital wastewaters, thus disrupting ecosystems and inducing microbial resistance. Here, we review the occurrence, toxicity, and removal of chloramphenicol with emphasis on adsorption techniques. We present the adsorption performance of adsorbents such as biochar, activated carbon, porous carbon, metal–organic framework, composites, zeolites, minerals, molecularly imprinted polymers, and multi-walled carbon nanotubes. The effect of dose, pH, temperature, initial concentration, and contact time is discussed. Adsorption is controlled by π–π interactions, donor–acceptor interactions, hydrogen bonding, and electrostatic interactions. We also discuss isotherms, kinetics, thermodynamic data, selection of eluents, desorption efficiency, and regeneration of adsorbents. Porous carbon-based adsorbents exhibit excellent adsorption capacities of 500–1240 mg g−1. Most adsorbents can be reused over at least four cycles.

Desorption of chloramphenicol from ordered mesoporous carbon-alginate beads: Effects of operating parameters, and isotherm, kinetics, and regeneration studies

This study has investigated the desorption of an emerging contaminant, known as chloramphenicol (CPC), from ordered mesoporous carbon (OMC)-alginate beads. The effects of initial concentration, operating temperature, and a selection of eluents (water, ethanol, and sodium chloride (NaCl)) on the whole desorption process were analysed. The desorption efficiency was found to decrease with increasing temperature, an indication for a favourable desorption process at a lower temperature range. NaCl was the most effective eluent for the CPC desorption process, followed by ethanol and water. The use of 1 M NaCl has resulted in the highest desorption efficiency of 84.7%. Redlich-Peterson and Freundlich isotherm models fitted well to the CPC desorption experimental data. The desorption kinetic data for ethanol and NaCl as eluents fitted well to the pseudo-second order kinetic model. Meanwhile, distilled water as an eluent was best fitted to the pseudo-first order kinetic model. The CPC adsorption efficiency began to notably decrease from 78.9% to 48.5% after five consecutive adsorption/desorption cycles. Similarly, the desorption efficiency began to decrease from 76.0% in the first cycle down to 35.2% in the fifth cycle. These findings demonstrated that the OMC-alginate beads are a very promising adsorbent with excellent desorption and reusability characteristics towards the targeted antibiotic, CPC.

SNW-1 Magnetic Solid Phase Extraction for HPLC Detection of Sulfonamides Residue in Milk

Objective Fe3O4@SNW-1 was prepared as an adsorbent in the magnetic solid phase extraction (MSPE) to pre-treat samples for HPLC determination on sulfonamides (SAs) in milk. Method A magnetic covalent organic framework (COF) material, Fe3O4@SNW-1, was hydrothermally synthesized to serve as the adsorbent in MSPE for the sample pretreatment. Parameters for the pretreatment, including adsorbent usage, adsorption duration, eluent selection, and elution time that affected the extract recovery, were optimized. HPLC was used to evaluate and determine the validity of the methodology. Result The optimized MSPE applying 2.0 mL ammonia-methanol (5 ∶ 95, V/V) as elution solvent, 60s for desorption, 4.0 mg of Fe3O4@SNW-1 as adsorbent, 120 s for adsorption at pH 6.0 to achieve linearities in the ranges between 10 ng·mL−1 and 100 ng·mL−1 on detecting 5 different SAs with correlation coefficients greater than 0.995. The HPLC detection limit on the SAs was 1.7-2.7 ng·mL−1. The daytime RSDs of 5 extraction replicates on the SAs (50 ng·mL−1 each) were 2.8–4.7%. The recovery rates on the SAs varied from 72.0% to 95.0%. Conclusion The proposed HPLC method with the MSPE sample pretreatment was convenient, rapid, specific, and effective for the determination of trace amounts of SA residues in milk.

Dampak Pemberian Ekstrak “Simbagh Utak” (Hydnophytum formicarum) Terhadap Penurunan Kadar Asam Urat Darah pada Mencit (Mus musculus) Jantan Hiperurisemia

One of Bengkulu's local culture is the utilization of medicinal plants by the people of Bengkulu, especially South Bengkulu, namely "Simbagh Utak" (Hydnophytum formicarum) for treating various diseases including Gout. However, they still use naturally, there is no scientific studied. This study was aimed to analyze the effect of “Simbagh Utak” (H. formicarum) on the reduction of serum uric acid levels in hyperuricemia male mice. This study used 25 male mice, that devided into 5 groups. The control group was given pellet feed (G1). We injected the high purine feed treatment per-oral to induce hyperuricemia (Negative control, G2) and then given H. formicarum extract 5.3mg/30gW (G3), 10.2mg/30gW (G4) and 21,2mg/30gW (G5). Uric acid measurements were performed using a digital method with easy touch /GCU. The tubers were extracted with maceration, eluent selection and isolation of the isolated components was carried out using thin layer chromatography and column chromatography. The extraction results were analyzed of functional groups using FTIR. The result showed that “simbagh utak” extract 5.3mg/30gW, 10.2mg/30gW and 21,2mg/30gW could reduced uric acid levels of hyperuricemia male mice 34.1%, 48.0% dan 53.4% respectively. On this basis, we conclude that "Simbagh Utak" extract could reduced levels of uric acid M. musculus males who have experienced a state of hyperuricemia (excess uric acid) very significantly at a dose of 21.2mg /30gW.

THE OPTIMIZATION OF ELUTING CONDITION OF SOLID PHASE EXTRACTION METHOD FOR -MANGOSTIN PURIFICATION IN MANGOSTEEN PERICARP EXTRACT

Objective: To obtain the optimum condition of eluent selection for purification of α-mangostin in mangosteen pericarp extract with solid phase extraction (SPE) method.Methods: The analysis was conducted by SPE cartridge octadecylsilane (ODS)-5, solvents used were methanol for conditioning, aqua bidestilated for washing and three different eluents for eluting: methanol, ethanol and ethyl acetate.Results: Recovery value for each eluent were 32.4741% for methanol, 46.6130% for ethanol and 33.6383% for ethyl acetate. Comparison of alpha-mangostin level in the mangosteen pericarp extract for each eluent i.e. 14.4578% for methanol, 10.0598% for ethanol, and 14.2898 % for ethyl acetate while compared to the extract without SPE was 21.7934%.Conclusion: Ethanol had the highest recovery value, compared to methanol and ethyl acetate.

Flow Injection Solid Phase Extraction for Trace Metal Determination Using a Chelating Resin and Flame Atomic Absorption Spectrometry Detection

ABSTRACTThe development of a simple and sensitive on-line flow injection preconcentration system is reported using a polyamino-polycarboxylic acid chelating resin for the automated determination of cadmium(II), chromium(III), copper(II), and lead(II) in natural waters and urine by flame atomic absorption spectrometry (FAAS). The adsorbent showed a high sorption affinity for the metal ions at pH values from 5.0 to 6.0. The retained analytes were efficiently eluted by 1.5 mol/L HNO3. The effect of chemical and hydrodynamic parameters such as pH, selection of eluent (type, volume and concentration), and sample/eluent flow rates were studied, providing optimum conditions for the analysis of real samples. For a preconcentration time of 120 sec, the sampling frequency was 22/h and the enhancement factors were 105, 49, 106, and 98 for cadmium(II), chromium(III), copper(II), and lead(II), respectively. The detection limits were between 0.1 and 1.6 mg/L, while the precision was less than 3.3% as the relative standard deviation for all metal ions. The accuracy of the method was evaluated by the analysis of certified reference materials and fortified environmental and biological samples.

Preconcentration of Trace Cadmium (II) and Copper (II) in Environmental Water Using a Column Packed with Modified Silica Gel-Chitosan Prior to Flame Atomic Absorption Spectrometry Determination

A new column loaded with modified silica gel-chitosan is proposed as a preconcentration system for adsorption of trace cadmium (II) and copper (II). The optimization steps were performed under dynamic conditions, involving pH, sample flow rate, eluent selection, concentration, volume, and flow rate. Trace Cd(II) and Cu(II) were quantitatively adsorbed by the modified silica gel-chitosan. The metal ions adsorbed on the separation column were eluted with 0.1 M HNO3 and determined by flame atomic absorption spectrometry. Under the optimum conditions, this method allowed the determination of cadmium and copper with limits of detection (LOD) of 20 ng L−1 and 38 ng L−1, respectively. The relative standard deviation values (RSDs) for 1.0 mg L−1 of cadmium and 1.0 mg L−1 of copper were 2.62% and 2.85%, respectively.

Controlled Immobilization of Polysaccharide Derivatives for Efficient Chiral Separation

AbstractPolysaccharide‐based chiral packing materials (CPMs) for high‐performance liquid chromatography (HPLC) have been widely used to determine the enantiomeric excess of a wide range of chiral compounds and also to resolve them on an industrial scale. These CPMs have conventionally been prepared by physically coating a chromatographic support with the polysaccharide derivatives. However, solvents that swell or dissolve the polysaccharide derivatives cannot be used as an eluent component because the column performance will be drastically decreased. This restriction on eluent selection is sometimes a serious issue for efficient analytical and preparative enantioseparations. In order to enhance the diversity of the eluent selection, immobilized CPMs, in which the polysaccharide derivatives are immobilized onto chromatographic supports, have been developed since 1987. This review summarizes the various immobilization methods of the polysaccharide derivatives mainly onto silica gel as a chromatographic support.

SIMULTANEOUS DETERMINATION OF ANIONS AND CATIONS IN ENVIRONMENTAL SAMPLES BY USING A WEAKLY ACIDIC CATION-EXCHANGE COLUMN WITH 2,6-PYRIDINEDICARBOXYLIC ACID, SULFOSALICYLIC ACID, AND 18-CROWN-6 AS ELUENT

Weakly acidic cation exchange resin can be used for simultaneous separation of anions and cations when acidic eluents were employed. On the weakly acidic cation exchange resin, anions were retained by ion exclusion mechanism, while cations by cation exchange mechanism. The selection of eluent is very important for the separation of interesting analytes. In this study, a mixture of 0.6 mmol/L 2,6-pyridinedicarboxylic acid (PDCA), 0.75 mmol/L sulfosalicylic acid (SSA), and 6.0 mmol/L 18-crown-6 was employed as eluent for the simultaneous separation of common inorganic anions (Cl−, NO3 − and SO4 2−) and cations (Na+, NH4 +, K+, Mg2+, and Ca2+). A good separation of these anions and cations on the weakly acidic cation exchange column (Tosoh TSKgel OApak-A) was achieved in 16 min. The linear range of peak area calibration curves for all analytes were up to two orders of magnitude. The conductivity detection limits calculated at S/N=3 were from 0.2 to 1.6 μmol/L for anions and cations. The method developed in this work was successfully applied to the simultaneous determination of major inorganic anions and cations in several environmental water samples.

Alkanesulfonate homologous series as eluent components in anion chromatography Novel eluent selection system for monovalent analytes

Common inorganic anions can be separated on an anion-exchange column of low capacity using a very dilute solution of alkanesulfonate as eluent components and a conductivity detector. A mathematical relationship has been found between the retention volumes of monovalent analyte using different alkanesulfonates as eluents and quaternary ammonium functionalized styrene-divinylbenzene stationary phase. Retention volumes decrease steadily for the homologous series of alkanesulfonates (methane-, ethane-, propane-, butane- and pentanesulfonates) as the alkyl-chain length increases. This system made it possible to establish the ion-exchange capacity of the separation column and the inter-eluent selectivity coefficients and permitted prediction of retention volume with variation of type and concentration of eluent. The parameters of retention model can be readily derived from elution experiments. The eluent system has been used easily to design separation schemes. Good agreement was obtained between the observed and predicted values for the anions of practical interest (fluoride, chloride, chlorate, nitrite, nitrate, bromide, bromate). Retention of ions can be manipulated by changing either the concentration or carbon number of the alkanesulfonate eluent from homologous series. The response of analyte retention to changing eluent conditions can be illustrated with a retention nomogram.

Highly Sensitive Method for Urea Detection in Wine

ABSTRACTTrace amounts of urea (less than 50 μg/L) in wine were accurately determined using a modified high performance liquid chromatography (HPLC‐fluorometric) technique. Appropriate selection of eluent, HPLC columns, and chiral derivatives for the o‐phthalaldehyde solution provided a 20‐fold enhancement of sensitivity over established methods. A linear relationship was observed at concentrations from 0.5–500 μg/L of aqueous urea solution. The threshold level for detectability of urea in wine was 5 μg/L. The method is simple enough to be applicable to most beverages.

Eluent Selection Criteria for the Simultaneous Determination of Anions and Cations

Eluent Selection Criteria for the Simultaneous Determination of Anions and Cations

Eluent selection for the determination of cations in ion chromatography

Literally thousands of eluent types can be used to separate ions in chromatography. Eluents are chosen and modified based on the interaction of the eluent and sample cations with the column. Cations can be separated by differences in their affinities for the column. Sample affinities are affected by ionic charge, eluent concentration and several other parameters. Cation separations can also be performed using complexing reagents to control selectivity.

Affinity constants in immunoadsorptive chromatography: their simple determination and application to the selection of eluents in and optimization of the elution process

A simple method is describe for the estimation of affinity constants of immobilised antibodies by measuring the ratio of bound antigen to immobilised antibody by the Mancini immunodiffusion technique, and representing the data in the form of a Langmuir adsorption isotherm plot of the reciprocal of the ratio of the bound antigen as abscissa. The slope of the resulting straight line is proportional to the equilibrium constant and the intercept on the ordinate is the reciprocal of the antibody valency. Sheep anti-human IgG immobilised on cyanogen bromide-activated Sepharose 4B® was employed in the measurement of the affinity constant fro the soluble affinity purified human IgG in several potential eluents. The qualitative and the quantitative effect of four potential eluents on human IgC antigen and sheep anti-human IgG antibody incubated in the four eluents for 24 h were also assessed by the Mancini technique. These results emphasise the importance of a knowledge of the affinity constant combined with quantitative data and effect of eluents and buffers on antibodies and antigens in immunoadsorption and their immunochemical procedures.

Ion-exchange in analytical chemistry: problems and prospects

Abstract