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Toxic Solvents (toxic + solvent)

Distribution by Scientific Domains
Life Sciences40%
Chemistry40%

Selected Abstracts

Assessment of acetone as an alternative to acetonitrile in peptide analysis by liquid chromatography/mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2009
Ria Fritz
Acetonitrile as a solvent used in liquid chromatography/mass spectrometry (LC/MS) of peptides and proteins is a relatively toxic solvent (LD50 oral; rat; 2,460,mg/kg) compared to alternatives like methanol (LD50 oral; rat; 5,628,mg/kg) and acetone (LD50 oral; rat; 5,800,mg/kg). Strategies to minimize its consumption in LC are either to reduce the inner diameter of the column or replace acetonitrile with a suitable alternative. Methanol is often recommended to replace acetonitrile in peptide analysis. In this study however, the main focus lies on another alternative solvent for LC/MS of peptides; acetone. A number of model proteins were tryptically digested and the peptide solutions were analyzed on a linear trap quadrupole (LTQ) mass spectrometer. The performances of acetonitrile, methanol and acetone were compared according to the quality of the chromatograms obtained and identification of the peptides using the BioWorksÔ software developed by Thermo Scientific. In accordance to the elutropic series, acetone was found to significantly reduce the retention times of peptides separated by C18 column material with regard to acetonitrile while methanol led to increased retention times. Acetone was the superior solvent to methanol for most of the tested model proteins reaching similar sequence coverage and numbers of identified peptides as acetonitrile. We therefore propose acetone as an alternative to acetonitrile in LC/MS of peptides. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Alternatives to VOC and toxic solvents in batch loaded cold cleaning

ENVIRONMENTAL QUALITY MANAGEMENT, Issue 1 2002
Mike Morris
First page of article [source]

Cellular response mechanisms in Pseudomonas aeruginosa PseA during growth in organic solvents

LETTERS IN APPLIED MICROBIOLOGY, Issue 3 2009
R. Gaur
Abstract Aims:, Solvent-tolerant bacteria have emerged as a new class of micro-organisms able to grow at high concentrations of toxic solvents. Such bacteria and their solvent-stable enzymes are perceived to be useful for biotransformations in nonaqueous media. In the present study, the solvent-responsive features of a lipase,producing, solvent-tolerant strain Pseudomonas aeruginosa PseA have been investigated to understand the cellular mechanisms followed under solvent-rich conditions. Methods and Results:, The solvents, cyclohexane and tetradecane with differing log P -values (3·2 and 7·6 respectively), have been used as model systems. Effect of solvents on (i) the cell morphology and structure (ii) surface hydrophobicity and (iii) permeability of cell membrane have been examined using transmission electron microscopy, atomic force microscopy and other biochemical techniques. The results show that (i) less hydrophobic (low log P -value) solvent cyclohexane alters the cell membrane integrity and (ii) cells adapt to organic solvents by changing morphology, size, permeability and surface hydrophobicity. However, no such changes were observed in the cells grown in tetradecane. Conclusions:, It may be concluded that P. aeruginosa PseA responds differently to solvents of different hydrophobicities. Bacterial cell membrane is more permeable to less hydrophobic solvents that eventually accumulate in the cytoplasm, while highly hydrophobic solvents have lesser tendency to access the membrane. Significance and Impact of the Study:, To the best of our knowledge, these are first time observations that show that way of bacterial solvent adaptability depends on nature of solvent. Difference in cellular responses towards solvents of varying log P -values (hydrophobicity) might prove useful to search for a suitable solvent for carrying out whole-cell biocatalysis. [source]

Industrial Potential of Organic Solvent Tolerant Bacteria

BIOTECHNOLOGY PROGRESS, Issue 3 2004
Yogita N. Sardessai
Most bacteria and their enzymes are destroyed or inactivated in the presence of organic solvents. Organic solvent tolerant bacteria are a relatively novel group of extremophilic microorganisms that combat these destructive effects and thrive in the presence of high concentrations of organic solvents as a result of various adaptations. These bacteria are being explored for their potential in industrial and environmental biotechnology, since their enzymes retain activity in the presence of toxic solvents. This property could be exploited to carry out bioremediation and biocatalysis in the presence of an organic phase. Because a large number of substrates used in industrial chemistry, such as steroids, are water-insoluble, their bioconversion rates are affected by poor dissolution in water. This problem can be overcome by carrying out the process in a biphasic organic-aqueous fermentation system, wherein the substrate is dissolved in the organic phase and provided to cells present in the aqueous phase. In bioprocessing of fine chemicals such as cis -diols and epoxides using such cultures, organic solvents can be used to extract a toxic product from the aqueous phase, thereby improving the efficiency of the process. Bacterial strains reported to grow on and utilize saturated concentrations of organic solvents such as toluene can revolutionize the removal of such pollutants. It is now known that enzymes display striking new properties in the presence of organic solvents. The role of solvent-stable enzymes in nonaqueous biocatalysis needs to be explored and could result in novel applications. [source]

An improved synthesis of 10,11-didehydro Cinchona alkaloids,

CHIRALITY, Issue 3-4 2008
Karol M. Kacprzak
Abstract A revised procedure for the conversion of the four major Cinchona alkaloids (quinine, quinidine, cinchonidine, and cinchonine) into their respective 10,11-didehydro derivatives is described. The reported protocol offers several advantages over a recently published synthetic route. These include (i) enhanced robustness (ii) ready scalability (iii) reduced operational complexity and number of steps (iv) chromatography-free work-up. In addition, toxic solvents were replaced by environmentally less problematic alternatives. Chirality, 2008. © 2007 Wiley-Liss, Inc. [source]