On-line microwave-based preconcentration device for inductively coupled plasma atomic emission spectrometry: Application to the elemental analysis of spirit samples

A microwave-based thermal nebulizer (MWTN) has been employed for the first time as on-line preconcentration device in inductively coupled plasma atomic emission spectrometry (ICP-AES). By the appropriate selection of the experimental conditions, the MWTN could be either operated as a conventional thermal nebulizer or as on-line analyte preconcentration and nebulization device. Thus, when operating at microwave power values above 100 W and highly concentrated alcohol solutions, the amount of energy per solvent mass liquid unit (EMR) is high enough to completely evaporate the solvent inside the system and, as a consequence, the analyte is deposited (and then preconcentrated) on the inner walls of the MWTN capillary. When reducing the EMR to the appropriate value (e.g., by reducing the microwave power at a constant sample uptake rate) the retained analyte is swept along by the liquid-gas stream and an analyte-enriched aerosol is generated and next introduced into the plasma cell. Emission signals obtained with the MWTN operating in preconcentration-nebulization mode improved when increasing preconcentration time and sample uptake rate as well as when decreasing the nozzle inner diameter. When running with pure ethanol solution at its optimum experimental conditions, the MWTN in preconcentration-nebulization mode afforded limits of detection up to one order of magnitude lowers than those obtained operating the MWTN exclusively as a nebulizer. To validate the method, the multi-element analysis (i.e. Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb and Zn) of different commercial spirit samples in ICP-AES has been performed. Analyte recoveries for all the elements studied ranged between 93% and 107% and the dynamic linear range covered up to 4 orders of magnitude (i.e. from 0.1 to 1000 μg L−1). In these analysis, both MWTN operating modes afforded similar results. Nevertheless, the preconcentration-nebulization mode permits to determine a higher number of analytes due to its higher detection capabilities.

Spirit Lake permanent outlet near Mount St. Helens, alternative strategies : environmental impact statement.

Mode of access: Internet.

History of the rise and influence of the spirit of rationalism in Europe,

Mode of access: Internet.

Directions for impregnating water with fixed air in order to communicate to it the peculiar spirit and virtues of Pyrmont water,

"Priestley and carbonated waters, by John J. Riley": p. [1]-17 (1st group)

The Catholic spirit in America,

Mode of access: Internet.

Musical development; or, Remarks on the spirit of the principal musical forms.

Mode of access: Internet.

Supplementary rules of the Shaker community : these are published to encourage the spirit of carefulness.

"Pamphlet probably written by H.C. Blinn. Published to accompany Authorized rules of the Shaker Community"--McKinstry.

The American citizen [electronic resource] : his rights and duties, according to the spirit of the Constitution of the United States. /

Electronic text and image data.

The Spirit maketh alive : an early Protestant view of Boston College /

"April 1991."