POTENTIOMETRIC DETERMINATION OF TRACE AMOUNTS OF CHLORIDE-ION IN FLOW-ANALYSIS USING ION-EXCHANGE PRECONCENTRATION

Uncertainty regarding the residual content of Cl- ion in highpurity water restricts the scope of traditional methods of calibrating potentiometric sensors in the low-concentration range using standard solutions. An alternative method is proposed in which low concentrations of chlorides (<10(-6) moles/liter) are determined by a potentiometric method after preconcentration on strong-base anion-exchangers with a low exchange capacity (almost-equal-to 10(-3) moles/g) as used in ion chromatography. This method opens up the possibility of developing an analytical scheme with potentiometric detection of preconcentrated Cl- ions directly in the eluate flow.