title: Flow gradient liquid chromatography using a coated anion exchange microcolumn.
abstract: Ion chromatography on a 4.0-mm-long (3.0 mm ID) ion exchange column is presented. Using a 10 mM phosphate buffer (pH 2.22) the separation of up to six UV-absorbing anions was obtained using the microcolumn, containing 5 microm RP support (Phenomenex Gemini) coated with the zwitterionic surfactant, (N-dodecyl-N,N-dimethylammonio) undecanoate. The short analytical column facilitated the application of a flow gradient programme over the flow range 0.3-5 mL/min resulting in optimum resolution of nitrite, nitrate, benzoate, iodide, thiocyanate and trichloroacetate in less than 10 min. The effect of both eluent concentration and pH on the retention of six selected anions was investigated, showing a strong pH capacity dependence. The microcolumn was found to exhibit no selectivity towards chloride and so was well suited to the analysis of saline samples. To illustrate this, the rapid analysis of a concentrated iodized table salt sample (20 g/L) was carried out. Following standard addition, a concentration of 3.55 +/- 0.05 microg iodide/g and 1.05 +/- 0.02 microg iodate/g in the solid salt sample was determined.
authors.affiliation: National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Ekaterina P
authors.initials: EP
authors.lastname: Nesterenko
authors.forename: Leon P
authors.initials: LP
authors.lastname: Barron
authors.forename: Pavel N
authors.initials: PN
authors.lastname: Nesterenko
authors.forename: Brett
authors.initials: B
authors.lastname: Paull
mesh_terms: D000838:Anions; D002021:Buffers; D002852:Chromatography, Ion Exchange / Q000295:instrumentation / Q000379:methods*; D005227:Fatty Acids; D006863:Hydrogen-Ion Concentration; D007454:Iodides / Q000032:analysis; D009994:Osmolar Concentration; D000644:Quaternary Ammonium Compounds; D012965:Sodium Chloride / Q000032:analysis; D013501:Surface-Active Agents
chemical_list: D000838:Anions; D002021:Buffers; D005227:Fatty Acids; D007454:Iodides; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D012965:Sodium Chloride; C093274:(N-dodecyl-N,N-dimethylammonio)undecanoic acid