Identify Mercury Contamination in Herbal Medicines with IC and ICP-MS

Application Note 43130 from Thermo Fisher Scientific combines Ion Chromatography and trace elemental analysis by Inductively Coupled Plasma Mass Spectrometry to investigate Hg content in herbal medicines.

These synergistic methods can provide the total solution and solve complex problems. Combining the synergies of two analytical techniques, speciation by Ion Chromatography (IC) and total multi-elemental analysis by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS), were used to solve the  source and clinical cause of a mercury poisoning cluster. When multiple patients had clinical symptoms of mercury poisoning and unusually high blood concentrations (mg/kg) of total mercury and lead by ICP-MS, the trail led to adulterated herbal medicines at 1-10 wt% total mercury  (by ICP-MS). To resolve this contradiction of 10,000x lower concentrations in the patients’ blood after ingesting herbal medicines with 1-10% mercury, mercury speciation was determined by IC with UV detection which found sub-percent concentrations of inorganic mercury and negligible concentrations of the more toxic mercury compound, methylmercury. Although the patients were very sick, these results agreed with the clinical symptoms rather than the total mercury results. However, IC is too specific to conduct a multi-element screening for an unknown contamination and therefore the synergies of IC with ICP-MS were both needed to solve the mercury poisoning cluster.

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