Microwave plasma, atomic spectroscopy

The metal content analysis of the samples was effected by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES Varian Liberty II Instrument) after microwaves assisted mineralisation in hydrofluoric/hydrochloric acid mixture. Ultraviolet and visible diffuse reflectance spectroscopy (UV-Vis DRS) was carried out in the 200-900 nm range with a Lambda 40 Perkin Elmer spectrophotometer with a BaS04 reflection sphere. HF was used as a reference. Data processing was carried out with Microcal Origin 7.1 software. 

Other frequently used methods for determining fluoride include ion and gas chromatography [150,204,205] and aluminium monofluoride (AIF) molecular absorption spectrometry [206,207]. Less frequently employed methods include enzymatic [208], catalytic [209], polarographic [210] and voltammetric methods [211], helium microwave-induced [212] or inductively coupled plasma atomic emission spectrometry [213], electrothermal atomic absorption spectrometry [214], inductively coupled plasma-mass spectrometry [215], radioactivation [216], proton-induced gamma emission [217], near-infrared spectroscopy [218] and neutron activation analysis [219]. 

Further designs of ion sources applied in plasma spectroscopy such as electrodeless microwave induced plasmas (MIPs) operating in a noble gas atmosphere at low power (mostly below 200 W) or capacitively coupled microwave plasma using Ar, He or N2 the as plasma gas (at 400-800 W) were described in detail by Broekaert.33 Microwave plasmas produced by a magnetron are operated at 1-5 GHz. Their special application fields for selected elements and/or element species are based (due to the low power applied) in atomic emission spectrometry.33... 

Inductively Coupled and Microwave Induced Plasma Sources for Mass Spectrometry 4 Industrial Analysis with Vibrational Spectroscopy 5 Ionization Methods in Organic Mass Spectrometry 6 Quantitative Millimetre Wavelength Spectrometry 7 Glow Discharge Optical Emission Spectroscopy A Practical Guide 8 Chemometrics in Analytical Spectroscopy, 2nd Edition 9 Raman Spectroscopy in Archaeology and Art History 10 Basic Chemometric Techniques in Atomic Spectroscopy... 

Buffington, R., GC-Atomic Emission Spectroscopy Using Microwave Plasmas, Hewlett Packard Corp., Avondale, PA, 1988. 

The decomposition of Co2(CO)8 in faujasites has been studied in some detail. Low-temperature spin-echo ferromagnetic nuclear resonance spectroscopy shows that very small Co particles are formed in supercages of zeolite NaX by microwave plasma activation at low temperatures (86). In situ far-infrared spectroscopy revealed that adsorbed Co2(CO)s interacts with accessible supercage cations in NaY and CoY (239). Carbonyl complexes of different Co nuclearity, such as Co4(CO)i2 and Co(CO)4, are also formed (227,228). In HY the Co atoms are oxidized to Co ions by the zeolite protons. 

Direct nebulization of an aqueous or organic phase containing extracted analytes has been widely used in flame atomic absorption spectroscopy [69-72], inductively coupled plasma atomic emission spectrometry [73-76], microwave induced plasma atomic emission spectrometry [77-80] and atomic fluorescence spectrometry [81], as well as to interface a separation step to a spectrometric detection [82-85]. 

Aziz A., Broekaert J. A. C. and Leis F. (1982) A contribution to the analysis of microamounts of biological samples using a combination of graphite furnace and microwave induced plasma atomic emission spectroscopy, Spectrochim Acta 37 381-389. 

AAS = atomic absorption spectrometry APDC = ammonium pyrrolidine dithiocarbamate APHA = American Public Health Association EPA = Environmental Protection Agency FPD = flame photometric detection ICP/AES = inductivity coupled plasma atomic emission spectroscopy MED = microwave emission detector MIBK = methyl isobutyl ketone NIOSH = National Institute for Occupational Safety and Health XRF = x-ray fluorescence... 

A completely different strategy for the surface functionalisation of CNTs with nitrogen-containing groups is the treatment of CNTs under atomic nitrogen flow obtained by molecular nitrogen dissociation in an Ar -t N2 microwave plasma. X-ray photoelectron spectroscopy of the nanotube surface demonstrated the presence of amides, oximes and mainly amine and nitrile groups. ... 

A plasma may be defined as a gas containing a relatively large number of ions and free electrons. To produce a plasma, an energy source is required and for analytical atomic spectroscopy three different excitation methods have been used. They are (1) a dc arc, (2) radiofrequency energy coupled through a microwave cavity, and (3) radiofrequency energy inductively coupled to the plasma. 

Rgure 1 A TMqio tyP resonant cavity. The position of the coupling loop and the viewing and cooling ports are shown. The discharge tube is centered in the holes at the top and bottom faces of the cavity. (Matousek JP, Orr BJ, and Selby M (1984) Microwave-induced plasmas Implementation and application. Reviews in Analytical Atomic Spectroscopy 7 275-314.)... 

J.A.C. Broekaert and V. Siemens. Recent trends in atomic spectrometry with microwave-induced plasmas. Spectrochimica Acta Part B Atomic Spectroscopy 59 1823-1839, 2004. 

GC with Bourier transform infrared spectroscopy (BUR) has been used for determination of chlorophenols in drinking water [95]. Before the GC-BUR analysis, the phenols were acetylated with acetic anhydride followed by off-line SPB using graphitized carbon cartridge. GC with microwave-induced plasma atomic emission spectroscopy was used in combination with two different off-line SPB procedures [96]. Derivatization with 3,5-bis(trifluoromethyl)benzyldimethylphenylammonium fluoride in combination with MS detection in negative chemical ion mode has been used for the determination of chlorophenols in industrial wastewater [94]. As seen earlier, SPB sample preparation is a commonly integrated part of the overall system setup in GC analysis. The technique is treated in more detail in the following section. 

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