Mercury and Antimony Troubleshooting

Wendy works at a radioactive treatment facility and wondered about using ICP-MS as a backup method for Hg analysis as compared to a FIMS instrument. Furthermore, Wendy noticed high background levels of Sb compared to her detection level when running antimony on her instrument. She was curious if Paul had any ideas about where this type of contamination might come from.

	RE: Mercury and Antimony Troubleshooting Dear Wendy,      The determination of Hg using ICP-MS is very tricky from a sample preparation perspective as well as the measurement perspective. Losses are often found due to both volatilization as well as adsorption to the container walls. Standard preparations of Hg in dilute nitric acid using plastic containers are not stable long enough to obtain reliable data and the washout times are long. If your FIMS approach is working, I do not suggest that you switch. If you are required to switch to ICP-MS, then contact me for further details on sample preparation and measurement.      Sb is a contaminant in some plastics. I would suggest that you perform a leaching study on the plastics involved in your analytical scheme to identify the source. Typically, ppb preparations of Sb in dilute nitric acid and LDPE containers are stable for months. We do provide isotopic standards for ICP-MS on a Custom Basis. Let us know the specifics and we'd be happy to provide you with a quotation. Thank you for your questions.     Paul R. Gaines, Ph.D. Serving you in chemistry