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New separation columns for ICNew IC columns complete the Metrohm range of products for ionchromatographyMetrohm has included various new IC separation columns in its product range. Inaddition to the favorably-priced Metrosep A Supp 10 (see report on page 14), wepresent three new columns for attractive special applications: Whether anions inbrine, the determination of pharmaceutical ingredients such as paracetamol andcaffeine or the isocratic separation of glycolate and acetate – Metrohm can now offersuitable columns for all these applications.Column specificationsColumn dimensions 250 mm x 4.0 mmSeparation material Polyvinyl alcoholwith quaternary ammoniumgroupsParticle size 5 µmpH range 3...12RecommendedprecolumnMetrosep RP Guard(6.1011.020)Metrosep A Supp 7 – 250 (6.1006.630)The Metrosep A Supp 7 has been specially developed for the simultaneous determinationof oxohalides, standard anions and dichloroacetic acid. However, thisimportant application is by far not the only field of use of this new high-performanceIC column. It is also ideally suitable for the isocratic separation of glycolateand acetate – this means that it is now possible to dispense with costly gradientsystems.The disinfection by-products (DBP) generated in water treatment plants are suspectedto be not only a general health hazard, but could even be carcinogenic.For this reason the oxohalides are the subject of many investigations and standardmethods (e.g. EPA 300.1 Part B, EPA 317.0). Most attention is being givento bromate, which is produced from bromide during the ozonization of drinkingwater.With the new Metrosep A Supp 7 IC column the oxohalides, standard anions anddichloroacetic acid can now be determined reliably and accurately down to the lowppb range. The polyvinyl alcohol separation material with a particle diameter of only5 µm guarantees extremely high plate numbers and thus high chromatographicefficiency. A temperature of 45 °C is required for the separation.A further interesting field of application for the Metrosep A Supp 7 is monitoring thecooling water in nuclear power plants. Too high ion concentrations accelerate thecorrosion of the piping systems and must therefore be avoided at all costs. Thismeans that an accurate monitoring system that functions 100% is absolutely essential.Apart from acetate, which is added to the cooling water as an additive, anyglycolate present as a contaminant also has to be determined.Glycolate and acetate are separated isocratically, that is without the use of agradient system that would otherwise be required for this application (see chromatogrambelow). Applying the preconcentration technique, it is possible to reliablydetermine concentrations as low as 100 ppt in the original solution.Determination of glycolate, acetate and formate besidesthe standard anions using the Metrosep A Supp 7 – 250IC column. As can be seen from the enlarged section ofthe chromatogram, glycolate and acetate are separatedat the baseline.Eluent: 3.5 mmol/L Na 2CO 3Flow rate: 0.8 mL/minSample: Standard containing 0.5 ppm fluoride,chloride, nitrite, bromide, nitrate, phosphate,sulfate; 5 ppm glycolate, acetate,formateTemperature: 45 °CDetection: Conductivity12 Metrohm Information Issue 2/2005