Electroreduction of heterotetranuclear complexes (~4-O)L~Cu4_~Ni~(H20)=C16 (x = 1-4, L = N,N-diet... more Electroreduction of heterotetranuclear complexes (~4-O)L~Cu4_~Ni~(H20)=C16 (x = 1-4, L = N,N-diethylnicotinamide) at a Pt electrode in dimethylsulfoxide leads to deposition of Cu-Ni alloys with codeposition of Cu(I) oxide, Ni(II) oxide, and Ni(II) hydroxide. The alloy deposition potential is invariant with complex stoichiometry. Alloy Ni composition, determined by x-ray diffraction (XRD), increases from 12% for x = 1 to 62% for x = 4. The microscopically rough, well-adhering, continuous films have a natural passivation layer formed by air oxidation that consists of Ni(OH)2, NiO, Cu(OH)2, and Cu20. X-ray photoelectron spectroscopy confirmed the bulk film alloy compositions obtained by XRD. The data revealed complex deposit structures consisting of NiO, Ni(OH)2, Cu20, and Cu-Ni alloy giving a mass balance of the metals in the complexes. The Cu20/Cu ~ ratio is close to unity for the deposit made from the Cu4 complex and decreases to zero for the CuNi3 complex. In contrast only half of the Ni(II) centers are deposited as Ni ~ in the Cu-Ni alloy, the balance consisting of 37% NiO and 15% Ni(OH)2. The constant percentage of Ni as Ni(OH)2 in all deposits suggests that it arises from reduction of Ni coordinated water. Mass balance indicates O in Cu20 and NiO originates from the ~4-O. Smooth variations of alloy compositions, metal oxide/metal ratios, and film particle sizes indicate that all the electrode processes involve discrete molecules of the heteropolymetallic complex. * Electrochemical Society Student Member.
Pretreatment and validation procedure for glassy carbon voltammetric indicator electrodes
Analytical Chemistry, 1985
Metallographic pretreatment procedures are described which yleid surfaces whose eiectrochemlcaiiy... more Metallographic pretreatment procedures are described which yleid surfaces whose eiectrochemlcaiiy active areas are Identical wlth their geometrlc areas. Glassy carbon indlcator electrodes (GCE) were used successfully in a stationary mode for cycllc ...
Using automated sequential two-dimensional gas chromatography/mass spectrometry to produce a library of essential oil compounds and track their presence in gin, based on spectral deconvolution software
Performance-Enhanced “Tunable” Capillary Microwave-Induced Plasma Mass Spectrometer for Gas Chromatography Detection
Performance evaluation of a gas chromatograph coupled to a capillary microwave-induced plasma mass spectrometer
Journal of Analytical Atomic Spectrometry, 1999
ABSTRACT A Hewlett-Packard Model 5890 series II GC, equipped with an on-column programmable press... more ABSTRACT A Hewlett-Packard Model 5890 series II GC, equipped with an on-column programmable pressure injector, was interfaced with a Hewlett-Packard HP 5971 mass-selective detector via a modified capillary MIP source from a Hewlett-Packard Model 5921A GC atomic-emission detector. The performance of the system was evaluated for the analysis of a 16 component mixture of organochlorine pesticides. Mixtures were separated on a Supelco PTE-5 column (30 m × 0.32 mm i.d.; 0.25 µm film thickness) with temperature-programming from 30-150°C at 20°C/min, from 150-270°C at 4°C/min, and from 270-300°C at 30°C/min. He was used as carrier gas at a constant flow of 1.5 ml/min and the analytes were detected by selected-ion monitoring at m/z 35. The MIP yielded peak intensities that were similar to or larger than those obtained by EIMS detection. Carbon deposition occurred when more than 10% diesel-oil (33% solution in hexane) was added to the organochlorine solution as a contaminant. However, the addition of N2 or O2 as a scavenger gas permitted the analysis of organochlorine pesticide mixtures containing up to 70% of diesel-oil mixture without compromising data quality. Recoveries of 16 pesticides, at the 100 ng/µl level, from such a mixture were in the range 79-110%.
Data Comparison Study Between Field and Laboratory Detection of Polychlorinated Biphenyls and Polycyclic Aromatic Hydrocarbons at Super fund Sites
Hazardous waste and hazardous materials, 1993
Page 1. HAZARDOUS WASTE & HAZARDOUS MATERIALS Volume 10, Number 4, 1993 Mary Arm Liebert,... more Page 1. HAZARDOUS WASTE & HAZARDOUS MATERIALS Volume 10, Number 4, 1993 Mary Arm Liebert, Inc., Publishers Data Comparison Study Between Field and Laboratory Detection of Polychlorinated Biphenyls and Polycyclic Aromatic Hydrocarbons at Superfund Sites ...
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