排序方式: 共有36条查询结果,搜索用时 414 毫秒
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Siemens Halske G. Grube F. Oettel H. Reinhardt B. Fetkenheuer E. Cremer P. S. Tutundžic A. Salminen E. R. Caley A. Glazunov J. Krieglstein Dorothy H. Brophy E. F. Smith L. G. Kollock K. Wagenmann M. L. Nichols E. L. Jewett H. Hölemann M. Garcia G. R. Fitterer R. Treje C. Benedicks B. L. Clarke H. W. Hermance Scheermesser E. Schmidt E. Tornow J. Heyrovský W. Kemula K. Suchý J. Prajzler A. Schleicher 《Analytical and bioanalytical chemistry》1933,91(5-6):197-210
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John Jewett 《Fresenius' Journal of Analytical Chemistry》1882,21(1):262-263
Ohne Zusammenfassung 相似文献
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Brent N. Jewett Louis Ramaley Jan C. T. Kwak 《Journal of the American Society for Mass Spectrometry》1999,10(6):529-536
This paper compares two liquid introduction atmospheric pressure ionization techniques for the analysis of alkyl ethoxysulfate (AES) anionic surfactant mixtures by mass spectrometry, i. e., electrospray ionization (ESI) in both positive and negative ion modes and atmospheric pressure chemical ionization (APCI) in positive ion mode, using a triple quadrupole mass spectrometer. Two ions are observed in ESI(+) for each individual AES component, [M + Na]+ and a “desulfated” ion [M − SO3 + H]+, whereas only one ion, [M − Na]− is observed for each AES component in ESI(−). APCI(+) produces a protonated, “desulfated” ion of the form [M − NaSO3 + 2H]+ for each AES species in the mixture under low cone voltage (10 V) conditions. The mass spectral ion intensities of the individual AES components in either the series from ESI(+) or APCI(+) can be used to obtain an estimate of their relative concentrations in the mixture and of the average ethoxylate (EO) number of the sample. The precursor ions produced by either ESI(+) or ESI(−), when subjected to low-energy (50 eV) collision-induced dissociation, do not fragment to give ions that provide much structural information. The protonated, desulfated ions produced by APCI(+) form fragment ions which reveal structural information about the precursor ions, including alkyl chain length and EO number, under similar conditions. APCI(+) is less susceptible to matrix effects for quantitative work than ESI(+). Thus APCI(+) provides an additional tool for the analysis of anionic surfactants such as AES, especially in complex mixtures where tandem mass spectrometry is required for the identification of the individual components. 相似文献
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G. L. Jewett R. P. Himes O. U. Anders 《Journal of Radioanalytical and Nuclear Chemistry》1977,37(2):813-821
The chemical separation techniques used at the Dow Chemical Co. are discussed. 相似文献
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