Helium microwave

Up to 30% hydrogen can be added to the carrier gas stream of a helium microwave plasma torch, in the determination of arsenic, bismuth and tin. The argon torch accepts up to 20% hydrogen LOD about 2.5 pg Sn/L, with linear dynamic range over 3 orders of magnitude23. 

Lobinski et al. [72] optimized conditions for the comprehensive speciation of organotin compounds in soils and sediments. They used capillary gas chromatography coupled to helium microwave induced plasma emission spectrometry to determine mono-, di-, tri- and some tetraalkylated tin compounds. Ionic organotin compounds were extracted with pentane from the sample as the organotin-diethyldithiocarbamate complexes then converted to their pentabromo derivatives prior to gas chromatography. The absolute detection limit was 0.5pg as tin equivalent to 10-30pg kg-1. 

River and marine sediments, soils Bu3Sn BujSn BuSn Capillary glc-helium microwave induced plasma emission spectrometric detection 0.0001-0.0003 [72] ... 

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]. 

J.M. Gehihausen, J.W. Carnahan, Determination of aqueous fluoride with a helium microwave-induced plasma and flow injection analysis. Anal. Chem. 61 (1989) 674-677. 

Story WC, Caruso JA. 1993. Gas chromatographic determination of phosphorus, sulfur and halogens using a water-cooled torch with reduced-pressure helium microwave-induced plasma mass spectrometry. J Anal Atomic Spectrometry 8 571-575. 

Figure 4.1 GC-MIP interface taken from The optimisation of an atmospheric pressure helium microwave induced plasma coupled with capillary gas chromatography for the determination of alkyl-lead and alkyl-mercury compounds (Greenway and Barnett, 1989).

Zhang, L. and Carnahan, J.W. (1989) Moving wheel liquid chromatography-helium microwave induced plasma interface. Anal. Chem., 61, 895-897. 

Lobinski, R., Dirkx, W.M.R., Ceulemans, M. and Adams, F.C. (1992) Optimization of comprehensive speciation of organotin compounds in environmental samples by capillary gas chromatography helium microwave-induced plasma emission spectrometry. Anal. Chem., 64, 159-165. 

Suyani, H., Creed, J., Caruso, J. and Satzger, R.D. (1989) Helium microwave-induced plasma mass spectrometry for capillary gas chromatographic detection speciation of organotin compounds./. Anal. At. Spectrom., 4, 777-782. 

J. Brill, B. Narayanan, et al., Selective determination of organofluo-rine compounds by capillary column gas chromatography with an atmospheric pressure helium microwave-induced plasma detector, HRC CC J. High Res. Chromatogr. Chromatogr. Commun., 11 368-374(1988). 

Halogenated - organic compounds Atomspheric pressure induced helium microwave induced plasma spectrometry Uses a - heated discharge tube for pyrolysis emission [282]... 

Chiba et al. [749] used atmospheric pressure helium microwave induced plasma emission spectrometry with the cold vapour generation technique combined with gas chromatography for the determination of methylmercuiy chloride, ethylmercury chloride and dimethylmercury in sea water following a 500-fold preconcentration using a benzene- cysteine extraction technique. 

Use of the Helium Microwave Induced Plasma for Speciation Studies... 

Work performed by the Caruso group [3,106-109] has encompassed several studies of the use of a He-MIP with mass spectrometric detection for chromatography, with particular application to speciation studies. As mentioned previously, the helium microwave induced plasma offers several advantages over conventional ICP-... 

Figure 19 Helium microwave induced plasma (M1P) torch used in MIP mass spectrometry (MIP-MS) sampling for capillary gas chromatography (GC) detection. (From Ref. 110.)...

B. D. Quimby, P. C. Uden, R. Barnes, Atmospheric pressure helium microwave detection system for gas chromatography, Anal. Chem., 50 (1978), 2112-2118. 

Hagen, D. R, Belisle, J., Johnson, J. D., Venkateswarlu, P. Characterization of fiuorinated metabolites by a gas chromatographic-helium microwave plasma detector - the biotransfor-... 

Chau, Y.K., Yang, F., Brown, M. Determination of methylcyclopentadienyl-manganese tricarbonyl (MMT) in gasoline and environmental samples by gas chromatography with helium microwave plasma atomic emission detection. Appl. Organomet. Chem. 11, 31-37 (1997)... 

Olson, L.K. Caruso, J.A. The helium microwave-induced plasma—An alternative ion-source for plasma-mass spectrometry. Spectrochim. Acta, Part B 1994, 49, 7-30. 

Nakahara T, Kawakami K, Tamotsu W. 1988. Continuous determination of low concentrations of mercury by atomic-emission spectrometry with helium microwave-induced plasma. Chemistry Express 3(11) 651-654. 

Pack B. W., Broekaert J. A. C., Guzowski J. P., Poehlmann J. and Hieftje G. M. (1998) Determination of halogenated hydrocarbons by helium microwave plasma torch time-of-flight mass spectrometry coupled to gas chromatography, Anal Chem 70 3957-3963. 

Tao H. and Miyazaki A. (1991) Determination of germanium, arsenic, antimony, tin and mercury at trace levels by continuous hydride generation-helium microwave-induced plasma atomic emission spectrometry, Anal Sci 7 55-59. 

Nakahara T., Yamada S. and Wasa T. (1990) Continuous-flow determination of trace iodine by atmospheric-pressure helium microwave-induced... 

Heltai Gy., Broekaert J. A. C., Leis F. and Tolg G. (1990) Study of a toroidal argon and a cylindrical helium microwave induced plasma for analytical atomic emission spectrometry - I. Configurations and spectroscopic properties, Spectrochim Acta, Part B 45 301-311. 

Wu M. and Carnahan J. W. (1990) Trace determination of cadmium, copper, bromine and chlorine into a helium microwave-induced plasma, Appl Spectrosc 44 673-678. 

Creed J. T., Davidson T. M., Shen W. and Caruso J. A. (1990) Low-pressure helium microwave-induced plasma mass spectrometry for the detection of halogenated gas chromatographic effluents, J Anal At Spectrom 5 109—113. 

The gas chromatograph may be interfaced with atomic spectroscopic instruments for specific element detection. This powerful combination is useful for speci-ation of different forms of toxic elements in the environment. For example, a helium microwave induced plasma atomic emission detector (AED) has been used to detect volatile methyl and ethyl derivatives of mercury in fish, separated by GC. Also, gas chromatographs are interfaced to inductively coupled plasma-mass spectrometers (ICP-MS) in which atomic isotopic species from the plasma are introduced into a mass spectrometer (see Section 20.10 for a description of mass spectrometry), for very sensitive simultaneous detection of species of several elements. 

Nojiri, Y., Otsuki, A. and Fuwa, K. (1986) Determination of sub-nanogram-per-liter levels of mercury in lake water with atmospheric pressure helium microwave induced plasma emission spectrometry. Anal. Chem., 58, 544-547. 

Such large amounts of data can only be sensibly and rapidly analysed and compared with reference spectra using microprocessors such as the fast 32 bit processors in PCs. The main systems in use today are discussed below, and in addition to the above mentioned techniques the microwave induced plasma (MIP) detector, a helium microwave plasma emission source coupled to a GC and an optical emission spectrometer are reviewed. 

A helium microwave cavity plasma or MIP serves as the heart of a unique instmment dedicated to the analysis of particles with diameters between 1 and 20 pim. The analysis of small particles is becoming increasingly important in fields as diverse as the semiconductor industry where extremely low levels of contaminants can destroy semiconductor chips, to indoor and outdoor air quality and the health impact of respirable particles. This instrument is basically an atomic emission spectrometer, but designed to count particles, calculate particle size, and determine the chemical composition of each particle analyzed, one by one. 

Skelly Frame, E.M. Suzuki, T. Takamatsu, Y. Particle characterization by helium microwave induced plasma spectrometry. Spectroscopy 1996, 11, 1. 

Fecher P.A. A. Nagengast. (1994). Trace analysis in high matrix aqueous-solutions using helium microwave-induced plasma-mass spectrometry. /. Anal. At. Spectrom., Vol.9, ppl021-1027, ISSN 1364-5544... 

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