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Reaction of metal-selenide colloids with DTNB.

By Marc Dauplais (166380), Myriam Lazard (166385), Sylvain Blanquet (166406) and Pierre Plateau (166411)


<p>Mixtures containing 50 µM sodium selenide and 100 µM of the metal ion under study were prepared in an anaerobic glove box and left to incubate in this box for 10 min at room temperature (180 min in the case of Fe<sup>2+</sup>). At time zero, 100 µM DTNB was added to the samples in the glove box. (<b>A</b>) Data with Co<sup>2+</sup>, Cd<sup>2+</sup>, Fe<sup>2+</sup>, Mn<sup>2+</sup>, Ni<sup>2+</sup>, Pb<sup>2+</sup> and Zn<sup>2+</sup> ions. TNB absorbance was followed at 412 nm. Data with Ca<sup>2+</sup> or Mg<sup>2+</sup>, which are similar to those with Mn<sup>2+</sup> or without metal, are not displayed in the figure. (<b>B</b>) Data with Ag<sup>+</sup>, Cu<sup>2+</sup> and Hg<sup>2+</sup> ions. TNB absorbance was followed at 390 nm instead of 412 nm (see Materials and Methods). In all cases, turbidities of the metal-selenide mixtures were measured in the glove box before DTNB addition. Corresponding values are indicated on the left side of the figure. Next, turbidities were measured just after DTNB addition. Because DTNB slightly absorbs light at 390 and 412 nm, values measured immediately after DTNB addition (0.25 min on the figure) systematically exceeded the values before DTNB addition (−1 min on the figure). With Ag<sup>+</sup>, Cd<sup>2+</sup>, Cu<sup>2+</sup>, Hg<sup>2+</sup>, Pb<sup>2+</sup> and Zn<sup>2+</sup>, the OD increments upon DTNB addition (0.065±0.005 and 0.24±0.01 at 412 and 390 nm, respectively) were close to those obtained in a control experiment without metal and selenide (0.060 and 0.24 at 412 and 390 nm, respectively). With Co<sup>2+</sup> and Ni<sup>2+</sup>, the increments at 412 nm were slightly higher (0.14 and 0.16, respectively). With Fe<sup>2+</sup>, the increment was far higher (0.45 at 412 nm, see Results).</p

Topics: Biochemistry, Microbiology, Chemistry, metal-selenide, colloids
Year: 2013
DOI identifier: 10.1371/journal.pone.0054353.g005
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Provided by: FigShare
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