I think Jim is completely retired. I haven't seen him at a conference or heard from him in at least 6 years, maybe 8.
I HAVE heard from one of his former students who, like Isaac, was also at a National lab and asked about the Spectral Systems ETV a while back, though I cannot remember which national lab, or the name of the former student. Hey, memory is the second thing to go with age, and I cannot even remember what went first.
Jim and his students always constructed their own ETVs from recycled GFAA systems, being the environmentally friendly group that they were, repurposing them as ETVs.
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
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). <[log in to unmask]> On Behalf Of SPARKS, Chris
Sent: Tuesday, May 15, 2018 10:01 AM
To: [log in to unmask]
Subject: Re: Ultra Clean Sapphire Digestion
Before Jim Holcombe reads this and wonders why none of his former students brought up ETV-ICP-MS, Isaac and I discussed on a private thread, though in more tongue in cheek terms than Dr. Pappas with his thought out reply. :-) Chris
Chris Sparks, Ph.D.
R&D Project Chemist
Air Liquide Electronics US/Balazs NanoAnalysis [log in to unmask]
On Tuesday, May 15, 2018, Pappas, Richard Steve (CDC/ONDIEH/NCEH) < [log in to unmask]> wrote:
> I would suggest borate fusion for sapphire, but the borate may also
> have trace uranium and thorium.
> The solid sample, ground would be better than a chunk, is an ideal
> candidate for ETV-ICP-MS with a reactive gas like carbon
> tetrachloride-saturated argon, or the CCl2F2 that Spectral systems
> suggests to volatilize the U and Th. Isotope dilution would work for U
> (keeping the U isotope in a chelating agent solution rather than an
> acid, which attacks pyrollytically coated graphite boats). Isotope
> dilution is not likely for Th, but maybe could use standard addition.
> 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 SPARKS, Chris
> Sent: Tuesday, May 15, 2018 12:19 AM
> To: [log in to unmask]
> Subject: Re: Ultra Clean Sapphire Digestion
> How smooth is the surface? TXRF may be an option
> I’ve done that analysis on sapphire wafers before with good results.
> It will be surface but the analytical spot size is about 1 cm diameter.
> Chris Sparks, Ph.D.
> R&D Project Chemist
> Air Liquide Electronics US/Balazs NanoAnalysis
> [log in to unmask]
> On Monday, May 14, 2018, Isaac Arnquist <[log in to unmask]> wrote:
> > Dear Plasmachemists,
> > I need to digest solid sapphire chunks (100-500 mg) in order to
> > measure the Th and U content...with part-per-trillion detection
> > limits. The material is being considered for ultralow background
> > physics detectors (think dark matter).
> > We have both CEM and Milestone microwave digestion systems. They
> > can both get up to 270C, or so, for upwards of an hour. Can you
> > recommend a digestion recipe? We've heard that 4 mL con sulfuric, 4
> > mL con phosphoric, and 1 mL con HF works at high temp, but the
> > reaction is
> ridiculously slow.
> > And the phosphoric acid is very contaminated with U and Th (and
> > pretty much any other metal, I presume, as it is not distillable).
> > Are there any other ideas out there? We fear any sort of fusion
> > will not provide adequate sensitivity levels to be interrogated
> > (lots of
> background contamination).
> > In order to increase reaction kinetics, we could grind the sample up
> > to a fine powder. Thus, grinding/milling processes will most likely
> > contaminate the sample, and leaves us scratching our heads in terms
> > of what to do about process blanks. Any ideas on how to CLEANLY
> > pulverize sapphire (it is the second hardest material on earth)?
> > Thanks,
> > Isaac
> > Isaac J. Arnquist, Ph.D.
> > Research Scientist
> > Radiation Imaging and Material Sciences Pacific Northwest National
> > Laboratory
> > 902 Battelle Boulevard
> > P.O. Box 999, MSIN J4-70
> > Richland, WA 99352 USA
> > Tel: 509-372-6531
> > Fax: 509-371-7869
> > [log in to unmask]
> > www.pnnl.gov