Can you tell us how the samples were prepared? What is the matrix? Are you standards matched to your matrix. Are you using an internal standard? Could it be that your samples have high dissolved solids and you have an issue with your nebulizer? When you did the Ag analysis did you also check Ag 107? It would be interesting to know if they agreed.
Clearly you have a problem but the community needs some more information to be able to help.
Dr William Perkins
Reader in Geochemistry
Department of Geography and Earth Sciences
Email: [log in to unmask]
Alias: [log in to unmask]
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). <[log in to unmask]> On Behalf Of Azam Noori
Sent: 01 June 2018 15:12
To: [log in to unmask]
Subject: Negative Data- ICP-MS
My name is Azam Noori. I am an assistant professor at Merrimack College. We have purchased an ICP-MS lately. It is NEXION 350X (Perkin Elmer). I am working with plants. I analyzed some samples yesterday. The calibration curve for most elements was good (Correlation factor: 0.998-0.999).
The concentration of elements in the first 5 samples was reasonable. Then I used the standard 10ppb as a sample to make sure the instrument is reporting the correct concentration. The concentration of most elements was much higher than 10 ppb in this sample. For example for silver (109), it was 623 ppb while when same sample was used as a standard the concentration was 9.88 ppb. I analyzed some samples after this, and the concentration of most elements (Ag, Mo, Cd, Sn, As, Ni, Fe, Cr, Pb, and V) in all samples were negative. It is not what I expected. Do you have any suggestions for troubleshooting?
Azam Noori, Ph.D.
Department of Biology
315 Turnpike Street
North Andover, MA 01845
Prifysgol Aberystwyth www.aber.ac.uk
Prifysgol y Flwyddyn ar gyfer Ansawdd Dysgu - The Times & The Sunday Times 2018.
Aberystwyth University www.aber.ac.uk
University of the Year for Teaching Quality - The Times & The Sunday Times 2018.