New pressure‐assisted sweeping on‐line preconcentration for polar environmentally relevant nitrosamines: Part 1. Sweeping for polar compounds and application of auxiliary pressure

Typically sweeping reversed migration EKC (RM‐EKC) is used for online enrichment and separation of neutral compounds in CE, however sweeping is not usually suitable for highly polar neutral compounds due to the lack of strong interaction with micellar phase. Since acidic BGE or coated capillaries (BGE pH 2–8) are used to virtually eliminate the EOF, migration of neutral analytes is only through association with the micelles with relatively slow electrophoretic mobility. To decrease the long analysis times that result, an auxiliary pressure can be applied, which also serves to avoid the associated band broadening. In this study, we have modified a commercially available CE instrument to perform pressure‐assisted sweeping. The apparatus described can be used to precisely control the application of pressure, and therefore direction and magnitude of bulk flow in the capillary. This modification allows us to employ longer capillaries and capillaries with larger internal diameter to increase the sensitivity. An optimized method was used for the analysis of a group of seven N‐nitrosamines that have been widely reported in environmental samples and good concentration factors of up to 34 were achieved. When a coated capillary is employed, this method is effective even at neutral pH, making it broadly applicable.     

Polyphenols in <Emphasis Type="Italic">Coreopsis tinctoria</Emphasis> Nutt. fruits and the plant extracts antioxidant capacity evaluation

The aim of this research was to investigate the chemical composition of Coreopsis tinctoria Nutt. fruits extract, to highlight the potential of ultrasound assisted extraction in the fast preparation of extracts rich in polyphenols using different solvents (55%, 78% and 96% hydrous ethanol) and to evaluate the antioxidant potential of formulated extracts. LC-MS/MS was used to characterize the ethanolic extract from Coreopsis tinctoria Nutt. dried fruits. The extract contains different flavonoids (marein, flavanomarein, quercetagetin-7-O-glucoside, okanin aurone, leptosidin, luteolin, apigenin) and phenolic acids (chlorogenic acid, caffeic acid). Several parameters that could affect extraction efficiency were evaluated. Finally, this study focused on determination of plant extracts total phenolic content and their antioxidant capacity. The experimental results allowed the selection of the optimum operating parameters leading to the highest total polyphenolic content, expressed as gallic acid equivalents, and avoiding the degradation of phenolic compounds (ethanol 55%; extraction temperature 323.15 K, extraction time 30 min, liquid/solid ratio 20/1). A good relationship between total phenolic content and antioxidant capacity was obtained.

Open image in new window

     

Aquatic fulvic acid as a matrix for matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric analysis

Aquatic fulvic acids (AFAs) are demonstrated to be effective matrices for the analysis of various polar compounds (ranging from 100–1500 Da) by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). The efficiency of AFA as a matrix is shown for a wide range of test compounds, including a number of carbohydrates, cyclodextrins and peptides, with typical detection limits of ～10 µg mL^?1. The propensity of AFA to enhance ionization through protonation of peptides, and formation of sodium and potassium adducts of carbohydrates and polyethylene glycol, was noted. Differences were observed in the performances of the two AFA matrices used, a Suwannee River, International Humic Substances Society (IHSS) standard and a locally extracted fulvic acid (LFA). For example, in the analysis of carbohydrate standards, the use of the LFA matrix typically doubled the analyte ion signal intensities and resulted in signal‐to‐noise (S/N) ratios that were 2–4 times better than when the Suwannee River AFA matrix was used. AFA was also used in the analysis of real‐world samples without extraction or purification; cantaloupe juice and acetaminophen tablets were analyzed, and glucose and acetaminophen could easily be identified as respective components. When lower concentrations of fulvic acid were used in the presence of sugars, a reversal of roles was observed in which the sugars functioned as the matrix and significantly enhanced ionization of the AFA components, while ions associated with the sugars themselves were suppressed or absent. Effective as a matrix for a variety of analytes and widely available, AFA is an attractive environmentally friendly choice for use in MALDI applications. Copyright © 2006 John Wiley & Sons, Ltd.     

Readily Synthesized Chiral Sulfides as Reagents for Asymmetric Epoxidation

Chiral oxathianes were designed, synthesized, and successfully used for asymmetric sulfur ylide mediated epoxidation. A considerable emphasis has been placed upon the design of sulfides with suitable architecture in a small number of steps (three or four). The use of (4aR,6S,8aR)‐6‐isopropenyl‐8a‐methyloctahydro‐1,4‐benzoxathiane in asymmetric epoxidation resulted in good diastereo‐ and enantioselectivity in the formation of stilbene oxide, and (2S,6S)‐2‐allyl‐2,3,3,6‐tetramethyl‐1,4‐oxathiane produced even better results. Moderate to good diastereoselectivities with essentially complete enantioselectivities were observed in the formation of alkyl–aryl‐, vinyl–aryl‐, and propargyl–aryl‐substituted epoxides. The selectivities were rationalized and supported by density functional theory calculations.     

Voice Quality Changes Following Phonatory-Respiratory Effort Treatment (LSVT®) Versus Respiratory Effort Treatment for Individuals with Parkinson Disease

Perceptual ratings of hoarseness and breathiness were used to assess the efficacy of two intensive methods for treating dysarthrophonia in individuals with idiopathic Parkinson disease. One method emphasized phonatory-respiratory effort (the Lee Silverman Voice Treatment, LSVT®) and the other emphasized respiratory effort alone (RET). Perceptual ratings were performed by two expert listeners based on random order presentation of the patients' pretreatment and posttreatment recordings of the “Rainbow Passage.” The listeners were blinded to the patients and their treatment group. Statistically significant pretreatment to posttreatment improvement in hoarseness and breathiness was observed in the LSVT® group but not in the RET group. The present findings are consistent with acoustic and physiologic findings reported previously, providing further evidence for the efficacy of the LSVT®.     

Glycerol as solvent and hydrogen donor in transfer hydrogenation-dehydrogenation reactions

Glycerol is employed successfully as a green solvent and hydrogen donor in catalytic transfer hydrogenation-dehydrogenation reactions. The glycerol donates hydrogen to various unsaturated organic compounds under mild reaction conditions and as a solvent, allows easy separation of products and catalyst recycling.     

Biofiltration methods for the removal of phenolic residues

Industrial effluents from the pharmaceutical industry often contain high concentrations of phenolic compounds. The presence of “anthropogenic” organic compounds in the environment is a serious problem for human health; therefore, it merits special attention by the competent public agencies. Different methods have been proposed in the last two decades for the treatment of this kind of industrial residues, the most important of which are those utilizing absorption columns, vaporization and extraction, and biotechnological methods. Biofiltration is a method for the removal of contaminants present in liquid or gaseous effluents by the use of aerobic microorganisms, which are immobilized on solid or porous supports. Although several bacteria can utilize aromatic compounds as carbon and energy source, only a few of them are able to make this biodegradation effectively and with satisfactory rate. For this reason, more investigation is needed to ensure an efficient control of process parameters as well as to select the suited reactor configuration. The aim of this work is to provide an overview on the main aspects of biofiltration for the treatment of different industrial effluents, with particular concern to those coming from pharmaceutical industry and laboratories for the production of galenicals.