Resin exchange preconcentration for MC analysis

Pre-concentration of Mercury in Waters for Stable Isotope Analysis by Ion-Exchange Resin

The following procedure is used by the U.S. Geological Survey’s Mercury Research Laboratory (MRL) for the pre-concentration of aqueous mercury (Hg) in large volume (> 2 L) water samples for analysis by multi-collector ICP-MS (MC-ICP-MS). This method utilizes the ion-exchange resin (AG1-X4) to pre-concentrate inorganic Hg from 10-20 L of water into a 30 mL elution solution. Samples are actively pumped through the resin, allowing quantitative collection of the aqueous Hg species onto the resin material. Afterwards a solution containing cysteine and citric acid is used to elute Hg that was retained on the resin. This method is used for natural waters with Hg concentrations that range from 0.5 ng/L to 50 ng/L. Quality assurance and control protocols are employed throughout the sample preparation including laboratory practices to prevent contamination and determination of percent recovery post elution.

Mercury Research Laboratory, 2021