Vapor techniques

In some cases, it may be convenient to dissolve a solid and present it for analysis as a solution that can be nebulized and sprayed as an aerosol (mixed droplets and vapor) into the plasma flame. This aspect of analysis is partly covered in Part B (Chapter 16), which describes the introduction of solutions. There are vaporization techniques for solutions of solids other than nebulization, but since these require prior evaporation of the solvent, they are covered here. There are also many solid samples that need to be analyzed directly, and this chapter describes commonly used methods to do so. 

The metal-vapor technique was applied to cobalt atoms and r-BuC = P (01JOM(635)212). The mixture of products that resulted includes the mixed-ligand sandwiches 170 and 171. Further interaction of complex 170 with [W(C0)5(THF)] leads to the coordination of the W(CO)5-group via the phosphorus heteroatom of the four-membered ring to yield 172. 

The first trifluorosilyl "organometallic compound, bis(trifluorosi-lyDmercury, has been prepared by using the new, metal-vapor technique (35). 

Cold on-column injection differs from the vaporization techniques discussed above in that the sample is introduced directly as a liquid into the column inlet, where it is subsequently vaporized. In this way, discrimination is virtually... 

Klabunde has reported limited reactivity toward oxidative addition reactions of carbon halogen bonds with nickel slurries prepared by the metal vaporization technique(65). 

The metal vapor method also has played an important role in the development of organometallic lanthanide chemistry (6-10). This high energy technique demonstrated that the lanthanide metals had a much greater range of organometallic chemistry than had been assumed previously. The metal vapor technique applied to lanthanides identified reasonable new research goals which could subsequently be pursued by solution techniques. Not only the metal vapor reactions. 

Hughes TJ, Simmons DM, Monteith LG, et al. 1987. Vaporization technique to measure mutagenic activity of volatile organic chemicals in the Ames/ Salmonella assay. Environ Mutagen 9 421-441. 

To optimize the applicability of the electrothermal vaporization technique, the most critical requirement is the design of the sample transport mechanism. The sample must be fully vaporized without any decomposition, after desolvation and matrix degradation, and transferred into the plasma. Condensation on the vessel walls or tubing must be avoided and the flow must be slow enough for elements to be atomized efficiently in the plasma itself. A commercial electrothermal vaporizer should provide flexibility and allow the necessary sample pretreatment to introduce a clean sample into the plasma. Several commercial systems are now available, primarily for the newer technique of inductively coupled plasma mass spectroscopy. These are often extremely expensive, so home built or cheaper systems may initially seem attractive. However, the cost of any software and hardware interfacing to couple to the existing instrument should not be underestimated. 

Elemental composition Hg 79.40%, C 9.51%, N 11.09%. Aqueous solution is analyzed for mercury metal by AA-cold vapor techniques or by ICP/AES (see Mercury). The cyanide ion may be measured by cyanide ion-specific electrode or by ion chromatography after appropriate dilution. 

Hughes, T. J., D. M. Simmons, L. G. Monteith, and L. D. Claxton, Vaporization Technique to Measure Mutagenic Activity of Volatile Organic Chemicals in the Ames/Salmonella Assay, Environ. Mutagen., 9, 421-441 (1987). 

LC-MS, as a technique, is very much dependent upon ionization (and ion vaporization) techniques that are suited to LC conditions, i.e. techniques where a relatively large solvent flow can be accommodated, which restricts us to just two ionization methods electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCl). Both techniques are very similar in their modes of operation (see Section 5.2.1), relying on the formation of a spray from a solvent flow at atmospheric pressure, and hence they are ideally suited to use in LC-MS applications. 

Butadiene d4 complexes were obtained (i) from [NbCU(dmpe)2] and magnesium butadiene (equation 87) j706 (ii) by dimerization of ethylene using alkylidenes (equation 88) 707 or (iii) by metal vapor techniques (equation 89), which yielded sublimable methylallyl derivatives.70 Compound (62) could not be prepared by Na/Hg reduction of (22) in the presence of butadiene. Compound (63) is also accessible from [TaH2ClL4] (Scheme 9). 

Determination of Mercury, Fluorine, Boron, and Selenium. The Determination of Mercury. A coal sample is decomposed by igniting a combustion bomb containing a dilute nitric acid solution under 24 atm of oxygen. After combustion, the bomb washings are diluted to a known volume, and mercury is determined by atomic absorption spectrophotometry using a flameless cold vapor technique. 

Cluster compounds with an Aun core can also be synthesized by the metal vaporization technique. Ethanol films containing L and LAuX at... 

The 253.7 nm analytical line is routinely used for AAS, although the 184.9 nm line is an estimated 50 times more sensitive. This line is beyond the wavelength where flame and atmospheric absorption are prohibitive. Using the cold vapor technique with a nitrogen-purged monochromator would permit greater sensitivity. 

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