The method uses a carbonate-bicarbonate eluent that is suppressed by the Xenoic® XAMS membrane suppressor continuously automatically regenerated by the Xenoic® ASUREX-A200. This gives low levels of background conductivity and noise, thus resulting in linear calibration curves and stable performance suitable for a routine quality control method.
Superimposed chromatograms from foscarnet assay calibration acquired on a Shodex IC SI-90 4E column (250×4 mm) using an eluent containing 7.5 mM NaHCO₃ and 7.5 mM Na₂CO₃ in water, pumped at 1.0 mL/min at 25 °C from an EQAX-B1 eluent bottle equipped with an EQAX-TC1 trap cartridge for carbon dioxide removal. Background reduced by XAMS suppressor with ASUREX-A200 automatic regenerator. Eluent pumping and conductivity detection by Metrohm 761 Compact IC. Injection of 20 µL of foscarnet (5, 10, 20, 50, 100, and 200 mg/L) in water, giving calibration signals up to about 9.3 µS/cm, or of phosphate (5 mg/L), to highlight method specificity.
Diduco is a leading provider of professional services in high performance liquid chromatography and manufacturer of the Xenoic® XAMS chemical suppressor and ASUREX automatic regenerator for ion chromatography.
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