Hydride generation-//? situ trapping

HPLC and hydride generation-/ situ trapping ETAAS were combined, the experimental conditions for the hydride generation being set after experimental designs... 

H. Matusiewicz and M. Mroczkowska, Hydride generation from slurry samples after ultrasonication and ozonation for the direct determination of trace amounts of As (III) and total inorganic arsenic by their in situ trapping followed by graphite furnace atomic absorption spectrometry, J. Anal. At. Spectrom., 18, 2003, 751-761. 

Table 1 summarizes the limits of detection of a number of hydride forming elements reported for the various generation-detection methods. For comparison with continuous sampling techniques, a 10 ml sample volume has been assumed for in situ trapping in the graphite furnace (although larger volumes are easily accommodated) and a 500 pi volume for FI approaches. It is clear that, despite the small sample... 

Simplex was used to optimise the best conditions to generate, transport and atomise Sb volatile species to determine total and inorganie Sb species at ultratrace levels by hydride generation and in situ trapping flame atomie absorption spectrometry. 

H. Matusiewiez and M. Krawezyk, Determination of total antimony and inorganie antimony speeies by hydride generation in situ trapping flame atomic absorption spectrometry a new way to (ultra)traee speeiation analysis, /. Anal. At. Spectrom., 2008, 23, 43-53. 

Alkyl mercuric hydrides are generated in situ by reduction of an alkyl mercuric salt with sodium borohydridc (Scheme 3.91). Their use as radical traps was first reported by Hill and Whitesides491 and developed for the study of radical-olefin reactions by Giese,489490 Tirrell492 and coworkers. Careful choice of reagents and conditions provides excellent yields of adducts of nucleophilic radicals (e.g. -hexyl, cyclohexyl, /-butyl, alkoxyalkyl) to electron-deficient monomers (e.g. acrylics). 

Palladium-catalyzed hydrostannation of isoprene was used for in-situ generation of allylstannane 9, which was trapped by an aldehyde to give alcohol 10 [Eq.(4)] [20]. It was suggested that an intermediate HPdSn(OAc)Cl2 is formed. The authors proposed two mechanisms for the hydrostannation, one according to Scheme 8-1 where Nu = Sn(OAc)Cl2 and another where insertion of the double bond into the palladium-tin bond is followed by reductive elimination from a (jr-allyl)palladium hydride. 

Enantiomerically enriched bishomoallylic alcohols could be readily accessed by reactions of 2-vinyloxiranes with chiral allylating agents based on a-pinene in the presence of a catalytic amount of Sc(OTf)3 [116]. The p,v-unsaturated aldehydes were generated in situ via Lewis acid induced rearrangement (1,2-hydride shift) and subsequently trapping by chiral allylboron compounds. The products were obtained in moderate to high yields with excellent enantioselectivities (Scheme 12.46). 

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