% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{Babay:57080, author = {Babay, P. A. and Gettar, R. T. and Magallanes, J.F. and Becquart, E.T. and Thiele, B. and Batistoni, D. A.}, title = {{C}olumn temperature as an active variable in the isocratic, normal-phase high-performance liquid chromatography separation of lipophilic metabolites of nonylphenol ethoxylates}, journal = {Journal of chromatography / A}, volume = {1157}, issn = {0021-9673}, address = {New York, NY [u.a.]}, publisher = {Science Direct}, reportid = {PreJuSER-57080}, pages = {227 - 236}, year = {2007}, note = {Record converted from VDB: 12.11.2012}, abstract = {Normal-phase separation of technical grade nonylphenol (t-NP, about $90\%$ 4-nonylphenol), 4-nonylphenol mono-ethoxylate (4-NP1EO) and 4-nonylphenol di-ethoxylate (4-NP2EO) was assessed, with the inclusion of column temperature as an active variable. The compound 2,4,6-trimethylphenol was evaluated for use as internal standard. Isocratic elution with 2-propanol/hexanes mixtures from an amino-silica column and spectrometric UV detection at 277 nm were employed. Technical nonylphenol presented a significant contribution from unknown substances that eluted with retention times similar to that of 4-NP1EO. GC-MS analysis of the unknowns allowed to identify them as isomers of 2-NP. The response of the system to joint variations in flow rate, eluent composition and column temperature was investigated by means of Doehlert statistical experimental design. A model for retention of the analytes as a function of the experimental variables was proposed, and separation selectivity was studied. Selection of the optimal working zone was made through desirability function (D) calculations. Potential co-elution of 2-NP isomers with 4-NP1EO was considered when optimizing the separation. The occurrence of a restricted region of the experimental space where baseline resolution of analytes, associated impurities and internal standard results feasible (D not equal to 0) is apparent.}, keywords = {Chromatography, High Pressure Liquid: instrumentation / Ethylene Glycols: isolation $\&$ purification / Ethylene Glycols: metabolism / Sensitivity and Specificity / Spectrophotometry, Ultraviolet / Temperature / Ethylene Glycols (NLM Chemicals) / terics (NLM Chemicals) / J (WoSType)}, cin = {ICG-3}, ddc = {540}, cid = {I:(DE-Juel1)ICG-3-20090406}, pnm = {Terrestrische Umwelt}, pid = {G:(DE-Juel1)FUEK407}, shelfmark = {Biochemical Research Methods / Chemistry, Analytical}, typ = {PUB:(DE-HGF)16}, pubmed = {pmid:17540387}, UT = {WOS:000248107200028}, doi = {10.1016/j.chroma.2007.05.038}, url = {https://juser.fz-juelich.de/record/57080}, }