False Detection of Cyanide Ion in Photographic Processing Waste Solutions Using Standardized Reference Methods

Abstract

Although cyanide compounds are not incorporated in photographic processing solutions, false detection of cyanide ion is often encountered during the determination of total cyanide by various standardized methods such as ISO, ANSI and JIS. Various organic compounds and nitrogen compounds in the processing solutions were examined because of this false detection. The results suggest that hydrogen cyanide is formed by a reaction between these compounds during the distillation process for the separation of total cyanide, even though ISO, ANSI and JIS were used. The results support the following three mechanisms of cyanide formation involved in the process: (1) Hydroxylammonium salts reacts with another ingredient, formaldehyde, to form formaldoxime, which then decomposes to HCN. (2) Hydroxylammonium is oxidized by air to form nitrite ion, which subsequently reacts with organic compounds such as aminocarboxylic acids and aromatic amines (the colour-developing agent) to form HCN. (3) Potassium permanganate oxidizes aromatic amines to form HCN.     

Synthesis of a novel bridged nucleoside bearing a fused-azetidine ring, 3′-amino-3′,4′-BNA monomer

A novel bridged nucleic acid monomer, 3′-amino-3′-deoxy-5-methyl-3′-N,4′-C-methyleneuridine, was successfully synthesized via a useful and convenient azetidine ring formation under Staudinger's conditions. A ¹H NMR experiment and a PM3 calculation revealed that the sugar moiety of the novel bridged nucleic acid monomer, 3′-amino-3′,4′-BNA, was restricted to S-type conformation.     

Unusual reactions of N-allylic difluoroenamines under thermal conditions

N-Allylic difluoroenamines exhibited unusual behaviors under thermal conditions; N-allyl difluoroenamines in refluxing xylene afforded not only aza-Claisen rearrangement products, but also 2-azabicyclo[2.1.1]hexanes, whose formation could be explained via intramolecular [2+2]-cycloaddition, whilst N-prenyl difluoroenamine underwent an ene reaction to give the pyrrolidine as a sole product.     

Physicochemical properties and stability in the acidic solution of a new macrolide antibiotic, clarithromycin, in comparison with erythromycin.

Clarithromycin (6-O-methylerythromycin), a new 14-membered macrolide antibiotic, has been studied to clarify its physicochemical properties and stability in acidic solution, as compared with erythromycin (EM). The solubility of clarithromycin (CAM) in distilled water was lower than that of EM and decreased with increasing temperature. The solubilities of CAM and EM in the phosphate buffer solution at 37 degrees C decreased with an increasing pH and kept constant above pH 9. From pH-solubility profiles, the dissociation constants of CAM and EM were determined to be 8.76 and 8.36, respectively. The partition coefficient of CAM took a higher value than that of EM and increased with an increasing pH. In the acidic solution, the decomposition of CAM and EM obeyed the pseudo-first order kinetics. From the decomposition rate constants, the half life (T1/2) of CAM and EM were determined. In pH 1.39, CAM degraded with a T1/2 of 17 min while EM kinetics corresponded to a T1/2 of 3 s. Therefore, CAM was 340-fold more stable in pH 1.39 and markedly more stable in the acidic solution than EM.     

Approaches to dioxin analysis by HRGC-HRMS and hybrid HRGC-MS-MS

A hybrid mass spectrometer with an EBQQ configuration was used to investigate two approaches to trace dioxin analysis: high resolution gas chromatography – high resolution mass spectrometry (HRGC-HRMS) and high resolution gas chromatography – mass spectrometry – mass spectrometry (HRGC-MS-MS). It is shown that selected ion monitoring (SIM) HRGC-HRMS exhibits better selectivity for dioxins separated on a cyanopropyl column than is otherwise obtained under medium resolution mass spectrometry (3,000 resolution), while optimization of conditions for HRGC-MS-MS allowed the observation of 350 femtograms of the highly toxic 2,3,7,8-TCDF at a S/N ratio of 5:1. Both methods were applied to environmental samples with good results.     

Parametrization of calcium binding site in proteins and molecular dynamics simulation on phospholipase A2

The empirical energy parameters for a calcium ion and its ligands in proteins were determined within a pairwise additive framework. The interaction energies of Ca²⁺-water, Ca²⁺-peptide group and Ca²⁺-carboxyl group systems were calculated using the ab initio molecular orbital method with basis sets of double zeta quality including polarization or diffuse functions. The resulting potential energy surfaces served as references for the determination of the nonbonded parameters in the empirical energy function. The nonadditive corrections for the Ca²⁺-ligand pair potentials are incorporated implicitly in the nonbonded paremeters by treating three-body (1:2 complex) or seven-body (1:6 complex) systems in reference calculations. Ligand polarizations induced by Ca²⁺ are estimated from the partial atomic charges of two-body (1:1 complex) systems. The charge sets were determined by scaling so as to reproduce the reference potential energy surfaces. The newly determined parameter set was used in a stochastic boundary molecular dynamics simulation of phospholipase A₂. The solvated structure of the Ca²⁺-binding site obtained from an X-ray crystallographic study is well reproduced by the parameter set.     

三甲基硅烷基丙炔与五甲基二硅烷基丙炔共聚物膜及其气体透过性

研究了三甲基硅烷基丙块与五甲基二硅烷基丙块共聚物〔poly(TMSP-co-PMDSP)〕的成膜特点。poly(TMSP-co-PMDSP)膜的气体透过系数分别为:P_(O2):4×10~3～12×10~3,P_(N2):3×10~3～8×10~3和P_(CO2):2×10~4～4×10~4barrer,气体透过稳定性低,透过行为偏离第二Fick定律,过系数下降,其中溶解系数降低的比例远大于扩散系数的增加比例,在含有凝聚性气体的环境里,膜的气体透过出现表面吸附控制的特征。     

Effect of Acid Treatment of Montmorillonite on “Support‐Activator” Performance to Support Metallocene for Propylene Polymerization Catalyst

This work is focused on montmorillonite (MMT)‐based “support‐activators” (S‐As) for the metallocene‐catalyzed propylene polymerization. This catalyst was previously industrialized; however, for further technological advances, the activation mechanism is investigated. The chemical and morphological requirements of the S‐A are surveyed using both commercially available raw clay minerals (non‐acid‐treated) and acid‐treated clay minerals. The S‐A possessing strong‐acid sites (pK a < ?8.2) gives a highly active catalyst. Acid treatment of MMT induces morphological changes as well as the formation of strong acid sites. Based on pore size distribution analysis and atomic force microscopy observations, it is concluded that the strong acid sites are located in the small pores around the edge of the clay mineral (not in the interlayer), where the structure is disordered by the acid treatment.

     

Development of 1,3a,6a-triazapentalene-labeled enterobactin as a fluorescence quenching sensor of iron ion

1,3a,6a-Triazapentalene (TAP)-labeled enterobactin was developed as an iron ion sensor. 3-Acetylated-TAP was successfully introduced to the catechol ring of enterobactin, a well-recognized siderophore secreted by various Gram-negative bacteria. The fluorescence of TAP-labeled enterobactin decreased gradually as the amount of Fe³⁺ ion as an additive was increased, and 1.2 equiv of Fe³⁺ ion completely quenched the fluorescence. In clear contrast, when other metal ions were used, the fluorescence of TAP-labeled enterobactin remained even at 5.0 equiv.     

Estimation of diffusion and permeability coefficients of CO2 in polymeric membranes by FTIR method

Infrared spectra of CO₂ sorbed in rubbery and glassy polymeric membranes were measured to examine the relationships between the spectroscopic data and the physical properties of the membranes. The two peaks observed in the spectra of CO₂ were attributed to the R branch and P branch of CO₂ sorbed in the membranes based on the consideration that both peaks were observed at a temperature above the glass transition temperature of the membranes. Apparent diffusion coefficients of CO₂ in the membranes were measured from the desorption kinetics of CO₂ detected by FTIR spectroscopy. The solubility coefficients of CO₂ were also estimated from absorbance spectra of CO₂ sorbed in the membranes using Lambert-Beer's rule. The permeability, solubility, and diffusion coefficients estimated by the FTIR method were found to correlate well with the coefficients obtained by conventional methods such as vacuum-pressure or sorption isotherm methods. © 1996 John Wiley & Sons, Inc.