Copper complexes sample preparation

When either the 2(6)2 + solution resulting from this process or a solution prepared from a sample of isolated solid 2(6)2 + (BF4 )2 were electrochemically reduced at — IV, the tetracoordinate catenate was quantitatively obtained. The cycle depicted in Fig. 14.3 was thus completed. The changeover process for the monovalent species is faster than the rearrangement of the Cu(II) complexes, as previously observed for the previously reported simpler catenate.16 In fact, the rate is comparable to the CV timescale, and three Cu species are detected when a CV of a CH3CN solution of 2(6)2 + (BF4 )2 is performed. The waves at + 0.63 V and —0.41V correspond, respectively, to the tetra- and hexacoordinate complexes mentioned above. By analogy with the value found for the previously reported copper-complexed catenane,16 the wave at —0.05 V is assigned to the pentacoordinate couple (Fig. 14.4b). 

Aqueous solutions of CuHis complexes, prepared in bi distilled water with a His Cu(II) ratio of 5 1 at pH 7.3 were used for ion exchange with NaY (ZEOCAT, Si AI = 2.71). A series of zeolite samples, differing in their amount of CuHis complexes, were prepared using solutions with different copper concentrations (0.1, 0.25, 0.50, 1.0, 1.5 and 4.5 copper/unit cell (Cu/UC)), while keeping the His Cu(II) ratio in the solution at 5 1 and the pH at 7.3. The pH was adjusted with 0.1 M NaOH and/or 0.1 M HCI solutions. All samples were stirred for 24 hours at room temperature. The pH of the exchange solution was measured regularly and adjusted if needed. All samples were dried at 333 K after washing and filtration. 

Emission spectroscopic techniques such as inductively coupled plasma optical emission (ICP-OES) and direct current plasma optical emission (DCP-OES). include the analysis of copper in biological materials (Delves et al.. 1983. Roberts et al., 1985). These techniques, with suitable sample preparation, have sufficient low bias and precision for clinical work but are more expensive and more complex than AAS (Herber et al.. 1982). Flow injection-ICP-OES will be mentioned below. 

All chemicals used were of reagent grade and millipore water was used throughout the work. A solution of L-trp (s.d. fine) was prepared by dissolving an appropriate amount of recrystallized sample in millipore water. A stock solution of osmium(VIII) was prepared and standardized by the method reported earlier [6]. The copper(III) periodate complex was prepared [7] and standardized by standard procedure [8]. 

Weiss and Mingioli established the structure of shikimic acid-3-phosphate, an intermediate on the shikimate pathway, as (4) by a comparison with a synthetic sample of shikimic acid-S-phos-phate (17) prepared from (9), Figure 2.1. Both acids reacted with periodic acid to show the presence of an a-glycol grouping but the dialdehydes formed in this reaction had markedly different spectral characteristics. The presence of a cis a-glycol grouping in (17) was confirmed by the relatively rapid reaction with periodate and the formation of a copper complex and an acetonide derivative. In contrast the natural phosphate ester (4) reacted slowly with periodate and did not form a complex with copper acetate nor an... 

In 1929, Linsted obtained samples of this complex from ICI chemists (Scottish Dyes Ltd was now owned by ICI). ICI had developed two routes leading to the phthalocyanine iron complex. One method started from phthalic anhydride, iron, and ammonia, while the second pathway proceeded from phthalimide, iron sulfide, and ammonia. In 1933/34, elucidation of the phthalocyanine structure was credited to Linstead. The corresponding copper and nickel phthalocyanines had been prepared in the meantime. ICI introduced the first Copper Phthalocyanine Blue to the market as early as 1935, and the Ludwigshafen subsidiary of the IG Farben-industrie followed suit with a corresponding product. 

To better elucidate the most critical impurities, a sample of the precipitated solid copper(II) complex formed by treating raw NaNT solution with copper(II) chloride was prepared for LC-MS analysis. As the unwanted impurities most likely precipitated following the addition of Cu11, this solid was an ap-... 

Khier et al. [30] determined mefenamic acid after complexation with copper(II) amine sulfate. The complex is extracted with chloroform and treated with diethyldithiocarbamate solution, whereupon another copper (II) complex (wavelength maximum of 430 nm) is formed. Beer s law is followed over the mefenamic acid concentration range of 6 18 pg/mL. The method was applied successfully to the determination of mefenamic acid in bulk samples and in pharmaceutical preparations, with recoveries of 98.0-101.0%. 

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