Amineboranes of the type L-BH3 (L = NH3; tert-BuNH2; Me2NH; Me3N) and sodium cyanotrihydroborate(III) (NaBH3CN) have been tested as derivatization reagents in the generation of volatile hydrides and elemental mercury following aqueous phase reaction with ionic species of Hg(II), As(III), As(V), Sb(V), Sb(III), Bi(III), Se(IV), Se(VI), Te(IV), and Te(VI). Continuous flow generation atomic absorption spectrometry coupled with a flameless quartz tube atomizer (T = 25 degrees C) and a miniature argon-hydrogen diffusion flame atomizer were employed for the detection of mercury vapors and volatile hydrides, respectively. All of the reductants were able to reduce Hg(II) to the elemental state, giving sensitivities comparable to NaBH4 reduction. Under reaction conditions giving maximum sensitivity for hydride generation with NaBH4, only some amineboranes are able to produce volatile hydrides from all the elements. No evidence of hydride formation was observed from the Se(VI) and Te(VI). In general, the reducing power decreased in the order NaBH4 > H3N-BH3 > tert-BuNH2-BH3 > NaBH3CN > or = Me2HN-BH3 > Me3N-BH3. In comparison with THB, amineboranes and NaBH3CN allowed, in general, a better control of interference effects of Fe(III), Ni(II), Co(II), and Cu(II). Application to determination of mercury in certified reference material is reported. The most likely mechanism of reaction of borane complexes in chemical vapor generation is based on the direct action of hydrogen bound to boron.
The simultaneous determination of Gd(3+) and Gd-DTPA (DTPA: diethylenetriamino-pentaacetic acid), often used as contrast agent, is described. The proposed approach combines size-exclusion chromatography (SEC) and inductively coupled plasma-mass spectrometry (ICP-MS) for element-selective detection in order to determine also high-molecular Gd-complexes if present. This method was applied to the analysis of urine samples of a patient to whom Gd-DTPA was intravenously administered. The results showed that no conversion or adsorption of Gd-DTPA could be observed in any sample, even free Gd(3+) could not be detected. Urine excretion behaviour was monitored and it was proved that Gd-DTPA was almost completely (>99%) excreted by urination within one day. Traces of Gd-DTPA could be measured in hair samples, but extraction with tetramethylammonium hydroxide (TMAH) resulted in degradation of Gd-DTPA.
Size exclusion chromatography (SEC) was coupled on-line to inductively coupled plasma mass spectrometry (ICP-MS) for speciation study of trace metals in cancerous thyroid tissues in comparison to healthy thyroids aimed to estimation of changes in metalloprotein speciation in pathological tissue. The study showed a presence of species binding Cu, Zn, Cd and Pb in healthy thyroid tissue with a good reproducibility of chromatographic results, whereas the same species could not be detected in cancerous tissues. Thus, remarkable differences with respect to metal-binding species were revealed between healthy and pathological thyroid samples, pointing out a completely different distribution of trace metals in cancerous tissues. The metal-binding species could not be identified in the frame of this work because of a lack of appropriate standards. Nevertheless, the results obtained confirm the suitability of SEC-ICP-MS for monitoring of changes in trace metal distribution in cancerous tissue and will help to better understand the role of metal-containing species in thyroid pathology.
Cd-bound phytochelatins (Cd-PCs) have been synthesised by incubation of Phaeodactylum tricornutum cell cultures with Cd and purified by size-exclusion chromatography-UV-Vis. These complexes, which were identified in previous work, have now been used as model substances to develop and optimise ion-pair chromatography (IPC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) for analysis of Cd-PCs. Subsequent analysis of samples taken from Silene vulgaris plants cultivated under heavy metal stress conditions revealed Cd signals but no Cd-PC signals. By use of isotopically enriched (116)Cd-PCs the sample preparation steps were verified to determine the stability of the analytes. We observed species transformation between Cd-PCs and other unidentified Cd complexes. Consequently, the kinetic and thermodynamic lability of Cd-PCs are decisive factors in their detection.
New on-line methods developed for the determination of Pt, Rh, and Pd by inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) include separation of elements which might lead to spectral interference in the quadrupole instrument. The fused-silica capillaries generally used for transport of the sample to mu-flow nebulizers have been chemically modified with ion-exchanger compounds to remove interfering elements such as Cu, Pb, or Hf. Characterization of the modification procedures by atomic-force microscopy showed that the quality of the quartz material and the kind of modification had a decisive influence on the yield of surface modification, and thus the exchange capacity of the capillaries.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.