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E. Schild K. P. Rath F. Stricker Ph. P. Gray I. M. Stone W. Siebenberg W. S. Hubbard G. Nowak C. Enders und H. Schoberth 《Fresenius' Journal of Analytical Chemistry》1937,110(7-8):298-299
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225.
H Pledger JR. G.-S. Wu T. S. Young T. E. Hogen-esch G. B. Butler 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9):1297-1307
Graft copolymers of acrylamide and yellow dextrin were prepared using cerium(IV) as initiator. The yellow dextrin had a very broad molecular weight distribution but was fractionated utilizing dialysis and ultrafiltration membranes. Initiator efficiencies were determined using size exclusion chromatography and were found to be between 2.4 and 34%. Initiator efficiency increased with acrylamide concentration at constant cerium (IV) and yellow dextrin concentrations, and decreased with increasing cerium(IV) concentration at constant acrylamide and yellow dextrin concentrations. Plots of acrylamide conversion and intrinsic viscosity vs initial acrylamide concentration at constant yellow dextrin and ceric ion concentrations showed a maximum at about 2.0 M. 相似文献
226.
Zheng Li Lovisa C. Romanoff Debra A. Trinidad Erin N. Pittman Donald Hilton Kendra Hubbard Hasan Carmichael Jonathan Parker Antonia M. Calafat Andreas Sjödin 《Analytical and bioanalytical chemistry》2014,406(13):3119-3129
Polycyclic aromatic hydrocarbons (PAHs) and their alkylated derivatives, such as methylnaphthalenes (MeNs), are harmful pollutants ubiquitously present in the environment. Exposure to PAHs has been linked to a variety of adverse health effects and outcomes, including cancer. Alkyl PAHs have been proposed as petrogenic source indicators because of their relatively high abundance in unburned petroleum products. We report a method to quantify 11 urinary methylnaphthols (Me-OHNs), metabolites of 1- and 2-methylnaphthalenes, and 10 monohydroxy PAH metabolites (OH-PAHs), using automated liquid-liquid extraction and isotope dilution gas chromatography tandem mass spectrometry (GC-MS/MS). After spiking urine (1 mL) with 13C-labeled internal standards, the conjugated target analytes were hydrolyzed enzymatically in the presence of ascorbic acid. Then, their free species were preconcentrated into 20 % toluene in pentane, derivatized and quantified by GC-MS/MS. The 11 Me-OHNs eluted as 6 distinct chromatographic peaks, each representing 1???3 isomers. Method detection limits were 1.0? 41 pg/mL and the coefficients of variation in quality control materials were 4.7???19 %. The method was used to analyze two National Institute of Standards and Technology’s Standard Reference Materials® and samples from 30 smokers and 30 non-smokers. Geometric mean concentrations were on average 37 (Me-OHNs) and 9.0 (OH-PAHs) fold higher in smokers than in non-smokers. These findings support the usefulness of Me-OHNs as potential biomarkers of non-occupational exposure to MeNs and sources containing MeNs. Figure
A gas chromatogram of a standard containing the trimethylsilyl derivatives of 11 methylnaphthols and 10 monohydroxylated PAHs (1 pg injection on column for 1- and 2-naphthol, 250 fg for the remaining analytes). 相似文献
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Ursula Palmer Colin Hubbard Ralph Puchta 《Journal of Coordination Chemistry》2015,68(17-18):2969-2970
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K. Bambach und D. M. Hubbard 《Fresenius' Journal of Analytical Chemistry》1941,121(7-8):296-297
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C. C. O'Loughlin Ernst Bornemann Prettner R. Meyer Marcusson Albert Sommer Dietrich Lohmann Hermann W. Mahr Prévost Hubbard F. P. Pritchard Charles F. Reeve Pritchard Gary André Dubosc S. W. Parr Brainerd Mears D. L. Weatherhead Heinrich Loebell Clifford Richhardson Eickmann Meyerheim Landsberger A. von Skopnik A. Scheller E. Graefe F. Schwarz G. Halphen D. Spiess Holde F. Meister Nastjukow Severin Charitschkoff Leopold Barta und A. P. Bjerregard 《Fresenius' Journal of Analytical Chemistry》1920,59(7):321-333
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