title: Application of the thermally tuned tandem column concept to the separation of several families of environmental toxicants.
abstract: Separations of several families of environmental toxicants were optimized by means of the thermally tuned tandem column (T3C) concept. We use a tandem combination of an octadecylsilane (ODS) and a carbon-coated zirconia (C-ZrO2) column; and tune the selectivity by independently adjusting the isothermal temperatures of the two columns. This results in the change in the contribution that each column makes to the overall retention and selectivity. The separation was optimized by locating the optimum pair of column temperatures which give the best separation of the critical solute pair. For both triazine herbicides and carbamate pesticides samples, dramatically different selectivities and different critical pairs were observed for the two types of phases. Although neither individual phase gave adequate separation, the T3C approach provided baseline separations using only four preliminary trial separations. We also showed that, for the triazine samples, the T3C approach gave a better separation than did conventional mobile phase optimization with an ODS column. The combination of superior selectivity of T3C and high flow rate allows the baseline separation of complex mixtures in just a few minutes.
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis 55455, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Mao
authors.forename: P W
authors.initials: PW
authors.lastname: Carr
mesh_terms: D002219:Carbamates; D004785:Environmental Pollutants / Q000032:analysis*; D006540:Herbicides / Q000032:analysis; D007202:Indicators and Reagents; D010573:Pesticide Residues / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet; D014227:Triazines; D015040:Zirconium
chemical_list: D002219:Carbamates; D004785:Environmental Pollutants; D006540:Herbicides; D007202:Indicators and Reagents; D010573:Pesticide Residues; D014227:Triazines; D015040:Zirconium; C028541:zirconium oxide