Cyrus Feldman

Mercury concentrations in fish from the great smoky mountains national park

Excessive mercury concentrations ostensibly due to pollution have been widely reported in fish tissue. The concentrations of mercury occurring naturally in fish tissue have not been well defined. A collection for mercury analysis of 198 fish of five species was made in 1972 in three high altitude streams in the Great Smoky Mountains, 20–25 km from the nearest pollution source. Mercury concentrations were (means, p.p.m.): rainbow trout Salmo gairdneri, 0.036; brook trout Salvelinus fontinalis, 0.018 ; banded sculpin Cottus carolinae, 0.025; rosyside aceClinostomus funduloides, 0.044; stoneroller Campostoma anomalum, 0.039. There was no significant difference in mercury concentration among fish analyzed whole, with gastrointestinal tract removed, or a strip of axial musculature. There was a significant (P0.05) difference in mercury concentration among species in one stream and in three species from different streams. A second collection of fish of the same species in 1973 verified the 1972 results. Methylmercury constituted 93 ±2.6% of total mercury. These results indicate that all fish acquire about the same tissue concentrations of mercury at chronic exposure to very low levels.

Variation of Cesium in the Ocean

Samples of sea water from several oceans and several depths were analyzed for natural cesium by flame photometry with precision of about 3.5 percent. The average of 16 assays of surface water from four oceans was 0.37 microgram per liter, somewhat less than the average previously reported. The average cesium concentration in samples taken between 500 and 1500 meters was about 14 percent higher than the surface average, suggesting that cesium may be transported downward by particulate material. Natural cesiumn is now somewhat easier to study in the ocean than radiocesium from fallout is, and information on one complements the other.

Detection of primary and secondary amines in energy-related materials using an element-selective glow-discharge detector

Abstract Mutagenic primary polycyclic aromatic amines present in shale oil and synthetic crudes may be readily detected by a simple derivatization and Chromatographic procedure. Nitrogenous bases and amines are extracted from the sample with dilute mineral acid and derivatized with trifluoroacetic anhydride. The derivatized amines are separated by gas chromatography and specifically detected using a glow-discharge detector tuned to an emission wavelength of fluorine. Under these conditions, the aromatic nitrogenous bases, such as acridine, are not detected even though they are present in the sample. As little as 14 ng of fluorine, arising from the derivative of 33 ng of 2,4,6-trimethylaniline, can be detected. The selectivity of the glow-discharge detector for derivatized amines vs. nonderivatized aromatic nitrogenous bases was estimated to be a minimum of 200:1.

SAMPLE TRANSPORT AND TEMPERATURE STUDIES IN POROUS-CUP DISCHARGES

Abstract High-speed colour motion pictures were taken of porous-cup discharges produced by a triggered polarized low-voltage condensed spark. These pictures indicated that soon after the trigger spark strikes the surface of the porous-cup electrode (PCE) a conical jet of solution vapour is emitted from another location on this surface. The discharge channel soon shifts to the axis of this vapour jet. The outer portions of the jet contain luminous fragments of water and solute molecules, but do not carry current. The interpretation of spectroscopic temperature measurements is discussed. A procedure is described for measuring the mean rotational temperature of the OH molecules in a transverse zone of the discharge; it is believed that these temperature values correctly reflect the excitation conditions to which vaporized solute atoms and ions are subjected. Near the PCE, where the discharge channel occupies almost all of the vapour jet, the. temperature appears to be governed by a Saha equilibrium. Near the counter-electrode, where the discharge channel occupies only a small fraction of the luminous cone, temperature appears almost independent of solution composition. Most emission of metallic lines occurs in the latter zone.

Application of a glow discharge detector to the determination of trimethylsilyl-derivatized complex organic mixtures

Abstract A helium glow discharge is employed as a gas Chromatographie detector which is selective for silicon. Operated with spectral background compensation at 251.6 nm or 288.2 nm, the detector shows a lower limit of detection of 5 ng of silicon per injection. The detector is applied to the rapid screening of trimethylsilylated fractions of shale-derived liquids being prepared for biossay.

The spectral detectability of fluorine in a helium glow discharge

Abstract The theoretical basis of the excitation of the fluorine emission spectrum is discussed, and the negative effects of easily excited impurities are demonstrated. Fluorine can be detected by means of its emission spectrum if it is present as a minor impurity in helium. The amount of water vapor and/or organic compounds in the helium must be minimized because these substances produce easily excited fragments in the glow discharge which dissipate the energy needed to excite fluorine atoms. Direct excitation of a diphenyldifluorosilane residue permits detection of about 70 pg of fluorine; if fluorine is volatilized as hydrofluoric acid and injected directly into the glow discharge, a photocurrent peak of 1.8 Ag-1 of fluorine is obtained.

Determination of gasphase—liquid phase (or other) distribution coefficients by analysis of one phase only

Abstract In measuring inter-phase distribution coefficients (k 1 11 )it is often convenient, and sometimes necessary, to obtain all of the analytical data from one phase. A rigorous formula, applicable to both low and high k 1 11 values has been derived; measurements of the distribution of mercury, methylmercury and 67Cu2+ between various pairs of phases with this formula gave k 1 11 values similar to those obtained from other approaches.

The Cooperative Standardization of Spectrographic Emulsion Contrast Factors

Some time ago, several members of the ASTM Committee on Spectrographic Analysis examined an experimental emulsion produced by the Eastman Kodak Co. to test its suitability for use in spectrochemical analysis. The reports agreed well on the three characteristics tested: graininess, speed, and uniformity of contrast with respect to wave-length. Although general adoption of the emulsion was not recommended, the way was opened for similar cooperative efforts in the future. This raised the prospect that Committee members and others might some day be asked to determine the contrast of a new — or old — emulsion at specified wave-lengths, under specified operating conditions.