Automated Logical Dilution for Ion Chromatography

To get accurate results in chromatography, the determined sample peak areas must be within the limits of the calibration. Moreover, high ionic concentrations can overload the column. Automated inline dilution of samples with Metrohm’s complete system of hard- and software for IC meets both challenges, thus providing accurate determinations of anions and cations. In order to perform automated dilutions, the 850 Professional IC, the 858 Professional Sample Processor and the MagIC™ Net software are additionally equipped with a magnetic stirrer and an 800 Dosino. The latter aspirates a defined volume of undiluted sample and transfers it to the mixing vessel. Subsequently the dilution medium, generally ultrapure water, is dosed into the mixing vessel. After intensive stirring, the peristaltic pump of the sample changer transfers the sample to the injection valve of the IC.

Alternatively, the sample can be injected directly. After the quantitation of the sample’s constituents, the software verifies if the peak areas lie within the calibration range. If this is the case, the next sample will be analysed. If not, the software, after calculating the dilution factor, will re-analyse the sample after applying the appropriate dilution. Whether the sample is diluted or directly injected, automated intelligent dilution ensures that peak areas are always within the limits of calibration.