Graphite furnace atomic absorption spectrometry and environmental challenges at the ultratrace level -- a review

Since its commercial introduction, the graphite furnace (GF) has enjoyed widespread use as a sensitive and selective ultratrace analytical technique. It possess several attributes which make it almost ideally suited for the various matrices encountered in the analysis of environmental materials. Although the instrumental technique has essentially matured in recent years, significant progress is continuing to be realized in the development of accessory hardware relating to sample introduction and processing. Since the GF can accommodate samples containing from 0% (vapours) to 100% (solids) dissolved solids content, sampling in all physical phases can be addressed using a variety of approaches. Additionally, complex chemical processing can be conveniently accomplished on-line, alleviating the need for extensive clean-room facilities while permitting information on element speciation to be obtained. Examples of conventional solution sample introduction, solid/slurry sampling and vapour generation techniques will be presented, as will sample preparation and separation and concentration strategies for both on- and off-line processing of environmental materials for ultratrace analysis.NRC publication: Ye

Exchange of comments on identification and quantitation of arsenic species in a dogfish muscle reference material for trace elements

[No abstract available

Headspace single-drop microextration for the detection of organotin compounds

International audienc

CARBON-OXYGEN REACTIONS IN GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY.

Heterogeneous reactions between oxygen and carbon have been investigated in the high-temperature graphite furnace by interfacing a Massmann-type atomizer to a gas chromatograph. Methanation of CO//2 and CO permitted their quantitation with a flame ionization detector. The primary product of combustion is CO whose concentration increases exponentially with temperature up to approximately 2 multiplied by 10** minus **3 atm at 2700 K. Minor amounts of CO//2, CH//4, C//2H//4, C//2H//2, and C//2H//6 ( less than 10** minus **5 atm) were also identified

Quantification of nitrite and nitrate in seawater by triethyloxonium tetrafluoroborate derivatization - Headspace SPME GC-MS

Triethyloxonium tetrafluoroborate derivatization combined with direct headspace (HS) or SPME-gas chromatography-mass spectrometry (GC-MS) is proposed here for the simultaneous determination of nitrite and nitrate in seawater at micromolar level after conversion to their corresponding volatile ethyl-esters (EtO-NO and EtO-NO2). Isotopically enriched nitrite [15N] and nitrate [15N] are employed as internal standards and for quantification purposes. HS-GC-MS provided instrumental detection limits of 0.07 \u3bcM NO2 - and 2 \u3bcM NO3 -. Validation of the methodology was achieved by determination of nitrite and nitrate in MOOS-1 (Seawater Certified Reference Material for Nutrients, NRC Canada), yielding results in excellent agreement with certified values. All critical aspects connected with the potential inter-conversion between nitrite and nitrate (less than 10%) were evaluated and corrected for by the use of the isotopically enriched internal standard. \ua9 2011 Elsevier B.V. All rights reserved.Peer reviewed: YesNRC publication: Ye

Mechanism of hydrogen transfer in arsane generation by aqueous tetrahydridoborate: Interference effects of AuIII and other noble metals

The generation of arsane by reaction of either NaBH4 (THB) or NaBD4 (TDB) in aqueous solution with AsIII (1 mg L -1) has been studied in the presence of several transition and noble metals at trace levels. A continuous flow generation system coupled with both atomic absorption spectrometry (AAS) and gas chromatography mass spectrometry (GC-MS) were employed to measure the effect of AuIII (0.5 - 20 mg L-1) on reaction yield and isotopic composition of arsane. In a different set of batch experiments, GC-MS was employed to measure the effect of AuIII, PdII, PtII, NiII and Cu II on the isotopic composition of arsane. AuIII, Pd II and PtII induce a significant perturbation in the mechanism of hydride generation, promoting the incorporation of a large amount of hydrogen derived from the solvent into the final arsane. This effect takes place at metal concentration levels which hardly affect the generation efficiency of arsane and can likely be addressed by the action of intermediate species formed in the early stage of the reaction between the metal ion and the TDB-arsenic complex. Nanoparticles and colloids arising from the interaction of the metal and TDB are able to capture the final arsane but they do not promote H/D exchange on the already formed arsane. This evidence reveals the existence of a new type of interference in chemical generation of volatile hydrides - a "mechanistic interference" - in addition to the already known yield interferences. \ua9 2011 Elsevier B.V. All rights reserved.Peer reviewed: YesNRC publication: Ye