Gregor A. Junk

THE ABSOLUTE ABUNDANCE OF THE NITROGEN ISOTOPES IN THE ATMOSPHERE AND COMPRESSED GAS FROM VARIOUS SOURCES

The absolute abundance of the isotopes in atmospheric and commercial compressed N2 from various sources has been determined. Nitrogen gas standards, prepared by mixing separated nitrogen isotopes in the form of (NH4)2SO4 solutions, were employed to calibrate two 60° sector mass spectrometers. As a result, the absolute ratio of N14/N15 in atmospheric nitrogen was found to be 272.0 ± 0.3 Small variations from this value were found for commercial compressed gas. The mass spectrometric procedure used in determining the N229+N228+ ratio allowed for detection of differences to 1 part in 3500. However, the absolute accuracy of the abundance measurements was limited to 1 part in 1000 because of the semi-micro Kjedahl distillation employed to determine the amount of (NH4)2SO4 present in the solutions of the separated isotopes. In these measurements, instrumental background played a very significant role. A reliable method of correcting the observed N229N228+ ratio for the contribution of the background at these mass position was developed.

A review of organic emissions from selected combustion processes

The 309 organic compounds reported in the literature as emissions from selected combustion processes are tabulated, with 109 originating from coal combustion, 213 from waste incineration and 69 from coal/refuse combustion. The largest percentage of components have been reported to be present in the grate ash from coal combustion, in the stack emissions from waste incineration and in the fly ash from coal/refuse combustion. Quantitative data for specific compounds are very incomplete, even for the more common components such as polycyclic aromatic hydrocarbons and polychlorinated biphenyls.

Solid phase extraction, GC separation and EC detection of tributyltin chloride

Abstract A new procedure for determining trace levels of tributyltin chloride (Bu 3 SnCl) present in seawater, without resorting to derivatization, has been developed. The stepwise approach involves: 1) solid phase extraction of Bu 3 SnCl from 100 ml of water using 100 mg of octadecyl (C-18) bonded porous silica; 2) elution with HCl treated ethyl acetate to collect 50 μl of the eluate; 3) on-column injection of 1 μl of the eluate and separation on a 15 m DB-5 fused silica capillary column; and 4) detection of pg quantities of Bu 3 SnCl by electron capture. Background and stability problems with both bonded porous and fused silica are described using test data from contrived and harbor water samples.

Energetics of the Ionization and Dissociation of Ni(CO)4, Fe(CO)5, Cr(CO)6, Mo(CO)6 and W(CO)6

The mass spectra of the metal carbonyls of Ni, Fe, Cr, Mo and W have been established. The ionization potentials and the energy necessary to form the various fragment ions have been measured. These data are used to calculate heats of formation for the various ions. The following dissociation energies were also calculated from the appearance potential data and ancillary thermochemical data and the valence state excitation energies: 1) specific bond dissociation energies for singly charged metal carbonyl ions, 2) average dissociation energies for singly charged parent ions, 3) average dissociation energies of neutral metal carbonyls to ground state products in which case comparison to calorimetric measurements are given, and 4) average dissociation energies of the metal carbonyls to valence state excited products. The unimolecular decomposition of metal carbonyls is discussed and the appearance potentials of the metal ions are used to calculate valence state excitation energies for the metal atoms. These values, W* = 3.18 eV, Mo* =4.92 eV, Cr* = 8.04 eV or 7.41 eV and Fe* = 6.57 eV are in excellent agreement with the observed spectroscopic values for Mo and with the values calculated from spectroscopic measurements of Cr and Fe. The value for the valence state excitation energy of W is the first reported in the literature.

Applications of resins for extracting organic components from water

ZusammenfassungDie verwendeten Harze, die Extraktionsvorrichtungen, einige Leistungstests sowie die allgemeine Methodik werden kurz beschrieben. Neue Entwicklungen von einfachen und wirtschaftlichen Verfahren zur Überwachung interessierender Verschmutzungsstoffe werden besonders erwähnt. Als Beispiele werden Wasserverunreinigungen durch PVC-Röhren, durch Pesticide, Amine, halogenierte Kohlenwasserstoffe sowie Modellverbindungen diskutiert. Das Verfahren der Sorption an Harz wird mit der Sorption an Aktivkohle sowie mit der Lösungsmittelextraktion verglichen. Ein neu entwickeltes Kleingerät zur Probenahme wird beschrieben.SummaryThe discussion of the applications is prefaced by very brief descriptions of: 1) the resin characteristics, 2) the extraction device, 3) some efficiency tests, and 4) the general methodology. Recent developments of simple and inexpensive procedures for the monitoring of selected contaminants of concern are stressed. Examples are given of the contamination of water by PVC tubes and of the measurements of pesticides, amines, halocarbons, and model compounds in water. Practical comparisons of the resin sorption method to carbon sorption and solvent extraction procedures are presented and recently developed mini-samplers are discussed.

Solid phase versus solvent extraction of pesticides from water

The average recovery for 12 pesticides spiked into 100 ml of water at 0.1 ppb was 90% when cartridges containing 100 mg of C-18 bonded porous silica were used for adsorption. Flow rates of up to 200 bed volumes per minute were employed for the adsorption step. Quantitative desorption of the pesticides was accomplished with less than 100μl of solvent, thus eliminating the need for a solvent reduction step. The pesticides from samples of surface waters were adsorbed onto C-18 bonded porous silica at the sampling site and the cartridges containing the bonded phase were returned to the laboratory for elution and analysis. The analytical results obtained from use of this procedure agreed with those obtained for duplicate samples of the water that were processed in the laboratory using standard solvent extraction procedures.

The partitioning of elements during physical cleaning of coals

Abstract The fate of 75 different elements was determined in coal samples before and after physical cleaning; in coarse coal wastes removed during cleaning; in process waters before and after the cleaning of coal; and in leachates of coal wastes. The results showed that the concentration of most elements simply followed the ash content of coal before and after cleaning. Germanium was significantly enriched and beryllium, molybdenum, uranium, iodine, cobalt and antimony were slightly enriched in cleaned coals. Sodium, sulfur, chlorine, calcium, iron, magnesium and potassium were observed in the process waters at concentrations above 100 mg/l with sodium at 860 mg/l being the highest concentration observed.

Dioxins not detected in effluents from coal/refuse combustion

Abstract No 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin was detected in effluents from a power plant burning coal supplemented with processed municipal wastes. These negative findings, in contrast with the many reports of the presence of dioxins from waste incineration, are proposed to be due to the high temperature of ∼1200°C for the combustion of small pieces of refuse with adequate oxygen for times sufficient to insure complete oxidation.

Organic emissions from combustion of combination coal/refuse to produce electricity

The compounds reported in the literatue by others and in this report are only some of the organic chemicals being emitted during production of electrical energy by combustion of coal and combination coal/refuse. The possible presence of more deleterious chemicals illustrates the need for a broader scope of analyses encompassing more accurate sampling and extraction schemes combined with improved separation and detection methods. Such developments are needed before accurate environmental impacts can be predicted. Classes of compounds reported include: polychlorinated biphenyls, other chlorinated compounds, polycyclic aromatic hydrocarbons, alkanes, carboxylic acids, phenols, phosphates, plasticizers, alkyl aromatics, and heterocyclic compounds.

Simplified determination of polycyclic aromatic hydrocarbons

Accurate quantitative analysis for selected polycyclic aromatic hydrocarbons present on urban dust can be obtained by using a simple procedure consisting of sonic-probe extraction with cyclohexane; clean-up with Florisil((R))-XAD-4((R)), and measurement by high-resolution gas chromatography with flame-ionization detection (HRGC/FID). The analysis can be further simplified by eliminating the clean-up step if HRGC/electron-impact mass-spectrometry (MS) is available. Both the FID and MS methods give results consistent with those obtained by standard procedures. The direct HRGC/MS procedure, combined with chemical ionization, can also be applied to the determination of polycyclic organic materials present in solvent-refined coal, shale oil and crude oil.