Certain impurities in the color additives drug and cosmetic (D&C) Red No. 21 (R21), D&C Red No. 22 (R22), and their lakes are limited to levels specified in the Code of Federal Regulations (CFR) and are quantified by the U.
View Article and Find Full Text PDFThis paper describes a simple and sensitive ultra-HPLC-triple quadrupole MS (LC-MS/MS) method for the determination of six unsulfonated aromatic amines in the color additives FD&C Yellow No. 5 (Y5) and FD&C Yellow No. 6 (Y6).
View Article and Find Full Text PDFAn ultra-performance liquid chromatography (UPLC) method was developed to determine the manufacturing intermediates and subsidiary colors in the monosulfo monoazo color additive D&C Red No. 34 and its lakes. This method is currently used for batch certification of the color additives by the U.
View Article and Find Full Text PDFThe synthesis, crystal structure, and spectroscopic characterization of [U(V)(H2O)2(U(VI)O2)2O4(OH)](H2O)4 (1), a mixed-valent U(V)/U(VI) oxide material, are reported. The hydrothermal reaction of UO2(2+) with Zn and hydrazine at 120 degrees C for three days yields 1 in the form of a dark red crystalline solid. Compound 1 has been characterized by a combination of single-crystal and powder X-ray diffraction (XRD), elemental analysis, thermogravimetric analysis, X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS).
View Article and Find Full Text PDFThe reaction of K28Li5H7[P8W48O184].92H2O with early lanthanides under hydrothermal and conventional conditions yields novel structures of the molecular formula Ln4(H2O)28K6Li7[K subsetP8W48O184(H4W4O12)2Ln2(H2O)10] congruent with 57H2O, Ln = La (1), Ce (2, 2a), Pr (3), Nd (4), in which the central cavity of the precursor anion is occupied by lanthanide cations and H4W4O12 moieties. The new heteropolyanions were characterized by elemental analysis, infrared spectroscopy, 31P NMR, and X-ray crystallography.
View Article and Find Full Text PDFThe first examples of polyoxometalate structures that incorporate embedded chelated heteroatoms point to new possibilities for stereochemical control of applications.
View Article and Find Full Text PDFReaction of Ce(III) with lacunary versions of [H(4)XW(18)O(62)](7-) (X = P, As) yields the 1:2 complexes [Ce(H(4)XW(17)O(61)](19-) (X = As, 1; P, 2) in good yield, characterized in solution and the solid state by NMR spectroscopy and X-ray crystallographic analysis, respectively. The structures confirm a syn C(2) conformation that is analogous to that observed for [Ln(alpha(2)-P(2)W(17)O(61))(2)](17-) but with "empty" O(4) tetrahedra that are in positions remote from the cerium atom. Bond valence sum calculations for these structures show that the four protons that are required for charge balance in all salts of the XW(18) anions and their lacunary derivatives are almost certainly bound to the oxygen atoms of the empty tetrahedra.
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