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Another Robert T. has that 14 part series on ICP-MS at:
www.stemvolunteers.org

Maybe he has something that can be cited somewhere in that series.

R. Steven Pappas, Ph.D.
Team Lead, Tobacco Inorganics Group
Centers for Disease Control & Prevention
4770 Buford Highway, NE
M.S. F44, Building 110
Atlanta, GA 30341-3717, USA

-----Original Message-----
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). <[log in to unmask]> On Behalf Of Taylor, Robert J
Sent: Thursday, May 10, 2018 3:20 PM
To: [log in to unmask]
Subject: Re: anomalously high Ni and Cr = contamination from stainless steel?

Steve, when we joined forces with another research group that used pipettes with the SS tip ejectors, one of the first things we did was to remove the tip ejectors and toss them in the trash.  Similarly, pipettes with the exposed metal threaded rod were consigned to permanent storage (and never used).  
I use a bottle top dispenser that's probably older than many list subscribers and still "offer up" the first 20 mL or so of nitric acid, putting this "first use" acid into a bottle where it's only used for acid-washing purposes.
Thanks.  If you're unaware of a reference, and having not received any other responses yet, it's possible that one may not exist.
Bob

Robert J. Taylor
Trace Element Research Laboratory
Department of Veterinary Integrative Biosciences College of Veterinary Medicine Texas A&M University College Station, TX 77843-4458

tel: 979-845-1568
fax: 979-847-8981




-----Original Message-----
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). <[log in to unmask]> On Behalf Of Pappas, Richard Steve (CDC/ONDIEH/NCEH)
Sent: Thursday, May 10, 2018 2:09 PM
To: [log in to unmask]
Subject: Re: anomalously high Ni and Cr = contamination from stainless steel?

Robert,
Not a reference, But we use a brand that does not have those stainless steel pipette tip ejectors.
Also, there is a bottle top dispenser that advertises inert sample path, but it has a platinum ball in the valve mechanism. If you stop using this dispenser for 30 minutes, in maybe the third or fourth sample, chromium and nickel (trace components of the platinum ball) sharply increase, then trail off as the leached Cr and Ni are rinsed out. The message is, avoid components in contact with, or even near acids that have a steel surface, and be aware that even 0.01% impurities from 99.99% pure Pt are sufficient to throw a monkey wrench into the works of ICP-MS sample prep. 

R. Steven Pappas, Ph.D.
Team Lead, Tobacco Inorganics Group
Centers for Disease Control & Prevention
4770 Buford Highway, NE
M.S. F44, Building 110
Atlanta, GA 30341-3717, USA

-----Original Message-----
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). <[log in to unmask]> On Behalf Of Taylor, Robert J
Sent: Thursday, May 10, 2018 2:34 PM
To: [log in to unmask]
Subject: anomalously high Ni and Cr = contamination from stainless steel?

Hello, plasmachemists.
In the course of analyzing many tissue samples, we have interpreted observation of anomalously high nickel and chromium as having originated from stainless steel.  One of the NIST SRMs had this issue, if memory serves, because stainless steel implements were used at some point for sample processing.  Similarly, we've inferred anomalously high values for both Ni and Cr as indicators of particulate contamination resulting from corrosion of stainless steel surfaces (HCl is not a friend to stainless steel).
Might anyone be aware of a reference to this observation?
Thanks-
Bob Taylor


Robert J. Taylor
Trace Element Research Laboratory
Department of Veterinary Integrative Biosciences College of Veterinary Medicine Texas A&M University College Station, TX 77843-4458

tel: 979-845-1568
fax: 979-847-8981