Chemicals & Chemistry

  2011 MAY 27 - (VerticalNews.com) -- "A freeze-dried mussel tissue certified reference material (CRM-FDMT1) containing multiple groups of shellfish toxins has been prepared. Toxin groups present in the material include okadaic acid and the dinophysistoxins, azaspiracids, yessotoxins, pectenotoxins, spirolides and domoic acid," researchers in Halifax, Canada report.

  "In this work, analytical methods have been examined for the characterisation of the candidate CRM. A comprehensive extraction procedure was developed, which gave good recovery (> 98%) for all lipophilic toxins studied. A fast liquid chromatography-mass spectrometry (LC-MS) method was developed that separates the major toxins according to the MS ionisation mode of optimum sensitivity. Matrix effects associated with analysis of these extracts using the developed LC-MS method were assessed. Standard addition and matrix-matched calibration procedures were evaluated to compensate for matrix effects. The methods and approaches will be used for the precise characterisation of the homogeneity and stability of the various toxins in CRM-FDMT1 and for the accurate assignment of certified values," wrote P. Mccarron and colleagues, National Research Council ...read more

  2011 MAY 27 - (VerticalNews.com) -- According to recent research from Halifax, Canada, "A candidate certified reference material (CRM) for multiple shellfish toxins (domoic acid, okadaic acid and dinophysistoxins, pectenotoxins, yessotoxin, azaspiracids and spirolides) has been prepared as a freeze-dried powder from mussel tissues (Mytilus edulis). Along with the certified values, the most important characteristics for a reference material to be fit-for-purpose are homogeneity and stability. ...read more

  2011 MAY 27 - (VerticalNews.com) -- According to a study from Vienna, Austria, "The action of Na+ incorporation into thin insulating films and transport therein under influence of a bias voltage and temperature (BT stress) is the subject of this work. Deposited onto highly n-doped Si wafers, the insulators get BT stressed and subsequently investigated by means of time-of-flight-secondary ion mass spectrometry (ToF-SIMS)."

  "A thin PMMA film, spin-coated onto the insulator, serves as host matrix for a defined amount of Na+, provided via sodium triflate. Combining BT stress and ToF-SIMS depth profiling enables the unambiguous detection of Na+, incorporated into the insulating material. The insulators of interest vary in their nitride content: SiO2, SiOxNy, and Si3N4. For SiO2, it is shown that once a threshold BT stress is exceeded, Na+ gets quantitatively incorporated from PMMA into the underlying insulator, finally accumulating at the SiO2/Si interface. A quantitative assessment by combination of Butler-Volmer kinetics with hopping dynamics reveals activation energies of E (a) = 1.55-2.04 eV for Na+ transport in SiO2 with varying thickness," wrote S. Krivec and colleagues, Institute of Chemical Technology ...read more