Showing papers in "Separation and Purification Reviews in 2008"

Nanofiltration Process Efficiency in Water Desalination

Abstract: Nanofiltration (NF) membranes have applications in several areas. One of the main applications has been in brackish and sea water treatment for drinking water production as well as for wastewater treatment. NF can either be used to treat all kinds of water including ground, surface, and wastewater or used as a pre treatment for desalination. The introduction of NF as a pre treatment is considered a breakthrough for the desalination process. NF membranes have the ability to remove turbidity, hardness, fluoride and nitrate as well as a significant fraction of dissolved salts. Desalination can be performed with a significantly lower operating pressure and becomes a much more energy‐efficient process. NF membrane transport properties, process prediction and modeling are very important. The ability to predict the performance of NF processes will allow for a reduce number of experiments, saving money and helping to understand the NF separation mechanisms. Several studies have investigated the partial and select...

Carbon Nanotubes as a New Solid‐Phase Extraction Material for Removal and Enrichment of Organic Pollutants in Water

Abstract: Among carbonaceous materials, carbon nanotubes (CNTs) distinguish many unique electronic, mechanical and chemical properties, high surface and excellent strength. They have been also proven to possess great potential as superior adsorbents. The characteristic structures of carbon nanotubes allow them to interact strongly with organic molecules, via non‐covalent forces, such as hydrogen bonding, π‐π stacking, electrostatic forces, van der Waals forces and hydrophobic interactions. This review presents a summary of the performance of CNTs for the removal and enrichment of different classes' organic pollutants in water. The use of carbon nanotubes as a tool in filters, membranes and sorbent material for solid phase extraction is discussed along with their sorption capacities and process parameters.

Chromatographic Residue Analysis of Sulfonamides in Foodstuffs of Animal Origin

Abstract: The widespread use of antibiotics in veterinary medicine for prophylactic, therapeutic and growth promoting purposes may result in the presence of residues in foodstuff of animal origin. Sulfonamides, N‐derivatives of 4‐amino‐benzenesulfonamide, belong to a diverse class of synthetic antibiotics consisting of chemically related compounds. A number of them e.g., sulfamethazine, sulfadiazine, sulfaquinoxaline and sulfamethoxypyridazine, are widely used in animal husbandry. Their residues in food are of great concern because of their potential carcinogenic character and because they may contribute to the development of antibiotic resistance in humans. These facts have induced most of the regulatory activities on sulfonamides. Regulatory bodies in the European Union as well as in other countries have set different maximum residue limits in various tissues. These regulations have stimulated the development of fast, accurate and sensitive analytical methods for monitoring sulfonamide residues in food samples of...

Part III: Supercritical Fluid Chromatographic Separations

Abstract: The enantioseparation of 123 clinically used racemic drugs by supercritical fluid chromatography (SFC) on commercial chiral stationary phases (CSPs) available in 2006 is reviewed. The CSPs were briefly described in Part I of this work. The mobile phase compositions, with organic modifier and additives, are listed. The data was extracted and compiled from the ChirBase database (Marseille, France). All the drugs included are listed according to the thirteen therapeutic classes of the Anatomical Therapeutic Chemical (ATC) classification. It is evident that the nature of the SF mobile phase precludes the use of several classes of CSPs such as the crown ethers, ligand‐exchange or protein‐based CSPs. The polysaccharide based CSPs were responsible for two third of the enantiomer separation listed.

Part II: From Dermatologicals to Sensory Organ and Various Drugs

Abstract: The enantioseparation of 442 clinically used racemic drugs by high‐performance liquid chromatography on commercial chiral stationary phases (CSPs) available in 2006 is reviewed The CSPs are briefly described in Part I of this work The data was extracted and compiled from the ChirBase database (Marseille, France) All the drugs included are listed according to the Anatomical Therapeutic Chemical (ATC) classification that defined thirteen therapeutic classes Only positive results are reported and, for a given CSP type, only the set of analytical conditions providing the best enantioselectivity is provided The analyst can find at a glance the optimal CSP column and its supplier, as well as the suitable mobile phase allowing for an efficient enantioresolution of a racemic drug Given the amount of data, Part I of this compilation included the technical and molecular description of exactly one hundred commercial CSPs and the six opening ATC classes with 211 enantiomeric drugs arranged from Class 1