Chromium occurrence in the environment and methods of its speciation.

A comprehensive review is presented of the extractive metallurgy of rare earths. The topics covered are: world rare earth resources and production; ore processing and separation of individual rare earths; reduction, refining, and ultrapurification of rare earth elements; methods for rare earth materials analysis; and a selection of the numerous rare earth applications. World rare earth reserves are abundant and would last for well beyond the next century. However, all of the 16 naturally occurring rare earth elements are not equally distributed in the ore minerals. This, compounded with the problems specific to the isolation and recovery of each of the rare earths, sets the stage for an unequal rare earth availability. The close chemical similarity of rare earths looses its importance when divergent physical properties determine the processes for rare earth element reduction and refining. The rare earth metals, alloys, and compounds have been as pure as could be determined. Finally, the commercial...

Extractive Metallurgy of Rare Earths

Commercial quartz crystal microbalances-Theory and applications

Novel multifunctional polymers from aromatic diamines by oxidative polymerizations.

Laccase is a widely studied enzyme because of its potential use in several areas such as textile, paper and pulp industries. This review presents the potential application of this enzyme in the food industry. Laccase can be used in bioremediation, beverage (wine, fruit juice and beer) processing, ascorbic acid determination, sugar beet pectin gelation, baking, and as biosensor and to improve food sensory parameters. Laccase could increase productivity, efficiency and quality of food products without a costly investment and has the advantage of being a mild technology.

Potential applications of laccase in the food industry

Pulse injection analysis with chemiluminescence detection: determination of citric acid using tris-(2,2'-bipyridine) ruthenium(II).

Instrument for Hadamard transform three-dimensional fluorescence microscope image analysis

The slurry sample introduction with fluorinating electrothermal vaporization has been applied to ICP-AES for the determination of boron in plant leaves. The main working parameters for ETV-ICP-AES, such as r.f. power, gas flow rate, drying temperature and atomization temperature have been studied. The concentration of the fluorinating agent polytetrafluoro-ethylene was examined for the boron determination. The matrix concentrations of Na, K, Ca and Mg up to 5 mg/ml do not interfere with the fluorinating vaporization of boron. Several plant samples were analysed with the standard addition method. A good agreement of analytical results between this method and a spectrophotometric method was obtained. The determined value of boron in NBS SRM 1573 tomato leaves coincides with literature values.

Slurry sample introduction with fluorinating electrothermal vaporization for the direct ICP-AES determination of boron in plant leaves

Organic solvent enhanced spectrofluorimetric method for determination of laccase activity

A method for the direct determination of Mo in various types of food by fluorination–electrothermal vaporization inductively coupled plasma atomic emission spectrometry has been developed and optimized. Slurry samples were prepared by ultrasonic wave vibration, after pre-treatment and direct injection into the graphite furnace using polytetrafluoroethylene as a fluorinating agent. The procedure was applied to the determination of Mo in National Institute of Standards and Technology Standard Reference Materials 1567 Wheat Flour, 1568 Rice Flour and 1577 Bovine Liver. The values found were in reasonable agreement with the certified values, with a detection limit of 0.7 ng ml–1 and an RSD of 3.2%(n= 10) at a concentration of 0.1 µg ml–1. The proposed procedure has been applied successfully to the analysis of various types of food samples; the recovery ranged between 92 and 105%.

Slurry sampling and fluorination–electrothermal vaporization inductively coupled plasma atomic emission spectrometry for the direct determination of molybdenum in food

Zeng Yun'e

Papers

Pulse injection analysis with chemiluminescence detection: determination of citric acid using tris-(2,2'-bipyridine) ruthenium(II).

Instrument for Hadamard transform three-dimensional fluorescence microscope image analysis

Slurry sample introduction with fluorinating electrothermal vaporization for the direct ICP-AES determination of boron in plant leaves

Organic solvent enhanced spectrofluorimetric method for determination of laccase activity

Slurry sampling and fluorination–electrothermal vaporization inductively coupled plasma atomic emission spectrometry for the direct determination of molybdenum in food