Harry Zeitlin

An x-ray fluorescence spectroscopic method for the determination of total manganese in rocks and marine sediments

Abstract A method for the determination of manganese by X-ray fluorescence is described. By using scattered X-rays as an internal standard, a linear calibration plot is obtained for standard rocks that agrees with the chemical data. The scattered X-ray method, compared with a widely used net-intensity method, shows improvement in accuracy especially at higher concentrations.

The Separation of Zinc and Copper from Seawater by Adsorption Colloid Flotation

Abstract Procedures are described whereby zinc and copper present as cations in seawater are brought to the surface in less than 5 min by an adsorption colloid flotation process which utilizes a negatively charged ferric hydroxide collector, a cationic surfactant, dodecylamine, and air. Statistical studies on test series show a mean recovery of 94.0% with a relative standard deviation of 6.1% for zinc and a mean recovery of 95.0% with a relative standard deviation of 6.1% for copper.

The role of iron(III) hydroxide as a collector of molybdenum from sea water

Abstract The behavior of iron(III) hydroxide was studied in order to clarify its role as a collector of the trace element molybdenum in sea water. Iron(III)hydroxide formed in sea water possesses a charge which is pH-dependent. At pH 4.0 the colloid has an apparent maximum positive-charge density and is able to adsorb molybdenum quantitatively as molybdate. Above pH 9 the charge is reversed and the iron(III) hydroxide no longer collects molybdate. Qualitative electrophoretic tests carried out in distilled water confirmed the positive and negative charge on the iron(III) hydroxide in acid and basic solution, respectively. At pH 10.0, calcium and magnesium salts coprecipitated molybdate in the presence or absence of iron (III) hydroxide. Procedures were worked out for the determination of molybdenum in sea water concentrated by iron(III) hydroxide at pH 4.0, and by calcium and magnesium salts at pH 10.0.

The separation of mercury from sea water by adsorption colloid flotation and analysis by flameless atomic absorption.

Abstract Adsorption colloid flotation has been found capable of separating ionic mercury from sea water quantitatively at levels as low as 0.02 μg l −1 with use of a cadmium sulfide collector and octadecyltrimethylammonium chloride as the surfactant. The mercury in 25 samples can be separated in 2 h. Following the separation the mercury was analyzed by flameless atomic absorption. Recovery of mercury from 0.5 l samples spiked with 0.010 μg of inorganic mercury gave sol|0.014 ± 0.002 μg/0.5 l. Black Point, Oahu near-shore sea water was found to contain mercury in the range 0.038–0.078 μg l −1 with no measurable organic mercury fraction. Sea-water samples collected at an open ocean station analyzed for total mercury revealed the highest mercury concentrations above 200 meters. Mercury concentrations in general showed a decreasing trend with increase in depth.

The separation of vanadium from sea water by adsorption colloid flotation

Adsorption colloid flotation can be applied successfully to the separation of selenium as SeO32- from sea water. Separation is achieved in 5 min. The modified catalytic method of West and Ramakrishna is used to determine the selenium. The recovery of selenium based on spiked sea-water samples is 100 ± 10%. Standard addition analysis of near-shore Oahu sea water showed a value of 0.40 ± 0.12 μg l-1.

The Separation of Phosphate and Arsenate from Seawater by Adsorption Colloid Flotation

Abstract Procedures are described whereby phosphate and arsenate in seawater are brought to the surface in less than 5 min by an adsorption colloid flotation process which uses a positively charged iron(III) hydroxide collector, an anionic surfactant, sodium dodecyl sulfate, and nitrogen. Statistical studies on test series show a mean recovery of 90.7 % with a relative standard deviation of 3.1 % for phosphate at the 3.0 μg-at./l level, a mean recovery of 91.2% with a relative standard deviation of 1.5% for arsenate at the 3.0 μ-at./l level, and a mean recovery of 94.1% with a relative standard deviation of 0.8 % for the combined 0.30 μg-at. AsO4 3−−As/l and 2.25 μg-at. PO4 3−−P/1 samples.

A modified nitroso-r method for the determination of cobalt in sea water

Abstract The existing colorimetric nitroso-R method for the determination of biologically important cobalt in sea water described by Thompson and Laevastu has been studied in detail, modified and improved. A procedure is recommended in which an approximately five-fold increase in sensitivity is achieved in the measurement of the nitroso-R chelate through close control of : pH, development time of complex, conditions for decomposition of excess reagent, and employment of a wavelength of 425 mμ. The size of the water sample required for an analysis is reduced from 10 to 21. For optimum results it was found necessary for a minimum period of 7 days to elapse following precipitation with sodium carbonate prior to filtration and analysis. A previously unreported salt effect in the procedure is described which requires either construction of a calibration curve from sea water spiked with cobalt or a correction in use of standards in distilled water. A precision was obtained with a 1–2% relative standard deviation throughout range of concentrations used, with an accuracy of 3.0% at 0.5 p.p.b.

The factors affecting the reflectance spectra of some dyes adsorbed on alumina

Abstract Various factors affecting the diffuse reflectance spectra of eosin B, rhodamine B, fuchsin, and o-nitrophenol adsorbed on Chromatographic alumina under various conditions were studied to explore the potential analytical application of reflectance spectroscopy to dyestuffs separated by thin-layer chromatography. Regeneration temperature, pH and grade of adsorbent, and humidity were found to influence the spectra but the technique may be utilized for the photometric analysis of food dyes adsorbed on alumina ; straight lines passing through the origin were obtained when the Kubelka-Munk function was plotted against a suitable concentration range of dye. For reproducible results, it is essential to employ the same grade of adsorbent and to prepare samples under uniform conditions of humidity.

The Separation of Collectors Used as Coprecipitants of Trace Elements in Seawater by Adsorption Colloid Flotation

Abstract Nine surfactants are screened for their ability to float six collectors, which have been used to coprecipitate trace metallic species in seawater, to the surface of seawater by adsorption colloid flotation as a function of pH.

The preconcentration of various trace elements in seawater by solvent extraction and the ring oven

Abstract A procedure is described for the preconcentration from seawater without pretreatment of six trace elements uranium, copper, nickel, cobalt, iron, and manganese through solvent extraction with an 8-hydroxyquinoline-chloroform mixture. Extracted samples are deposited on filter-paper disks with the aid of a kinetic clamp pump and a ring oven, and the six elements are determined non-destructively by X-ray fluorescence. Evaluation of the procedure with distilled water and seawater samples spiked with the metal ions shows that extraction of the trace metals is essentially quantitative.