Contamination Issues: Eliminating High and Erratic Blanks
Guillaume contacted Inorganic Ventures to find out whether we knew of a published paper with the values of Environmental Contamination: Table 8.1, Effect of Laboratory Atmosphere on Pb Blank Levels. He noted that his lab was having some problems with the lead blanks values (ICP-MS), which appeared random to him.
We used to use leaded gasoline in the USA, making ppb level Pb determinations nearly impossible. The basic rule back then was to work in the hood only if you must as it was the greatest area for contamination because of increased air exposure, but always keep the sample covered. Most contamination today is from apparatus and reagents.
I would like to suggest that you perform blanks in and away from the hood and covered and uncovered, with varying amounts of reagents etc. in order to identify the source of contamination (air, apparatus, operator, or reagents). All four areas come into play with trace Pb determinations and each laboratory must perform their personal studies to identify, and hopefully eliminate, high and erratic blanks.
Thank you for contacting Inorganic Ventures and for your question.
Serving you in chemistry,
Paul R. Gaines, Ph.D.
CEO of Inorganic Ventures & Fellow Chemist
DISCLAIMER: Advice offered by the chemists at Inorganic Ventures is intended for the individual posing the question. Feel free to contact us to verify whether these suggestions apply to your unique circumstances.