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11.
Benn TM Pycke BF Herckes P Westerhoff P Halden RU 《Analytical and bioanalytical chemistry》2011,399(4):1631-1639
There is a growing concern about the human and environmental health effects of fullerenes (e.g., C(60)) due to their increasing application in research, medicine, and industry. Toxicological and pharmacokinetic research requires standard methods for extraction and detection of fullerenes from biological matrices such as urine. The present study validates the use of liquid-liquid extraction (LLE) and solid-phase extraction (SPE) methods in conjunction with liquid chromatography-mass spectrometry (LC-MS) for the quantitative determination of C(60) in human and synthetic urine as compared with ultrapure water. Glacial acetic acid, which is necessary to prevent emulsions during LLE, inhibited C(60) detection by LC-MS, but this could be mitigated with evaporation. Aqueous C(60) aggregates (nC(60)) were spiked at 180 μg/L into the components of a synthetic urine recipe to determine their individual impacts on extraction and detection. Urea, creatinine, and a complex protein (i.e., gelatin) were found to impair SPE, leading to a low recovery rate of 43 ± 4% for C(60) spiked into human urine. In contrast, C(60) was consistently recovered from synthetic matrices using LLE, and recovery in human urine was 80 ± 6%. These results suggest that LLE combined with LC-MS is suitable for studying the clearance of fullerenes from the body. LLE is a robust technique that holds promise for extracting C(60) from other complex biological matrices (e.g., blood, sweat, amniotic fluid) in toxicological studies, enabling a better understanding of the behavior of fullerenes in human and animal systems and facilitating a more comprehensive risk evaluation of fullerenes. 相似文献
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Reinhard Benn 《Magnetic resonance in chemistry : MRC》1983,21(12):723-726
The low-temperature 1H NMR spectra of bis(ethylene)trimethylphosphinenickel (1), η5-cyclopentadienyl(ethylene)methylnickel (2a), bis(ethylene)-η5-cyclopentadienylcobalt (2b), [bis(1-ethyl-2,4,6-triphenylphosphorinyl)nickel]P,P′-nickel(ethylene) (3) and η5-cyclopentadienyl(ethylene)hydrido(triphenylphosphine)ruthenium (4) exhibit {AA′B′B} (1) {ABB′A} (2a and 2b), {ABA′B′} (3) or {ABCD} (4) spin patterns, respectively, for the complexed ethylene. A full line shape analysis including all the proton couplings was performed for the ethylene rotation in 1, 2a and 2b. In addition to olefin rotation, a reversible intramolecular β-H-elimination was confirmed for 4 by magnetization transfer experiments. 相似文献
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1J(13C13C) has been determined in naturally abundant samples of η1,η2 -alkenyl-η5 -cyclopentadienylnickel complexes; for the coordinated double bonds 1J(CC) lies between the value for free ethylene and cyclopropane, and therefore gives direct insight into the relevant bonding situation. 相似文献
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M. Parvez P. Kulanthaivel M. H. Benn 《Acta Crystallographica. Section C, Structural Chemistry》1998,54(3):IUC9800005-IUC9800005
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Using the correspondence between the Clifford and exterior algebras we write the Dirac equation in terms of differential forms. The covariances of the theory are then examined. We show in detail the correspondence with usual matrix methods. 相似文献
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