21127-45-7Relevant articles and documents
Chromium(VI) oxide oxidation of non-ethoxylated and ethoxylated alcohols for determination by electrospray ionization mass spectrometry
Beneito-Cambra, Miriam,Bernabe-Zafon, Virginia,Simo-Alfonso, Ernesto F.,Ramis-Ramos, Guillermo
experimental part, p. 2093 - 2100 (2011/11/06)
A new derivatization procedure to increase the sensitivity of electrospray ionization mass spectrometry (ESI-MS) to non-ethoxylated and ethoxylated alcohols was investigated. The analytes were oxidized with chromium(VI) oxide and the resulting carboxylic and ethoxy-carboxylic acids were isolated by extraction with ethyl acetate; the extracts were alkalinized and infused into the ESI-MS system working in the negative-ion mode. The yields of the combined oxidation-extraction were ca. 100% for non-ethoxylated fatty alcohols dissolved in acetone and they decreased moderately in samples containing increasing amounts of water (e.g., a 75% yield was obtained with 50% water). Ethoxylated alcohols with more than two ethylene oxide units resulted in yields of ca. 60%. Low limits of detection (LODs) were obtained when the procedure was applied to the analysis of body- care products and cosmetics containing fatty alcohols, e.g., in a varicose-vein cream, the LODs were 25 μ cetyl alcohol and 7.5 μ stearyl alcohol (detected as palmitic acid and stearic acid, respectively) per gram of sample. High molecular mass alcohols were also detected in seawater after pre- concentration by solid-phase extraction. Thus, the proposed method is particularly valuable for use in industrial samples having complex matrices and in environmental samples and it is competitive with other methods for the analysis of trace amounts of fatty alcohols.
Extraction of Zn(II), Cd(II), and Hg(II) by dodecyloligo(oxyethylene) carboxylic acids
Strzelbicki, Jerzy,Charewicz, Witold,Beger, Jorg,Hinz, Lutz
, p. 1695 - 1700 (2007/10/02)
The synthesis of a series of n-dodecyloligo(oxyethylene) carboxylic acids of general formula C12H25(OCH2CH2)nOCH2COOH (n=0 to 5) and application of these compounds for the separation of Zn(II), Cd(II), and Hg(II) in extraxtion are reported.Negligible extractability of the metal ions investigated was found using dodecyloxyacetic acid (n=0) which indicated that complexation resulted from metal-cation interaction with oxygen atoms of the polyoxyethylene chain incorporated into the molecule of complexon.In extractions from aqueous solutions containing ZnCl2, CdCl2, HgCl2, and NaOH (pH regulator), loading of the organic phases increased for extractants with more oxyethylene units.In particular, Hg(II) extractibility and molecular structure of the extractant are related.The selectivity of extraction increased drastically if NaCl was added to the initial aqueous phase, as the extractibilities of Cd(II) and, particularly, Hg(II) declined while the extractibility of Zn(II) remained high.Selectivity of extraction is produced by the complex chemical equilibria resulted from complexation of the metal cation by an alkyloligoether carboxylic acid in the organic phase and by Cl(1-) and OH(1-) anions in the aqueous phase.Thus, aqueous solution parameters greatly influence the efficiency and selectivity of the extraction process and suitable experimental conditions are very important.
