I agree with all of the comments suggesting that it sounds like Ag is
plating out on the sample introduction components. You said that you
replaced the sample intake components. If this problem is persisting I'd
make sure that everything the solution touches has been replaced including
probe, sample lines and the containers that you have your standards in.
*Riley Murphy PhD*
On Wed, May 16, 2018 at 11:15 AM, Guy Reggio <[log in to unmask]> wrote:
> Are Mass Calibration and Pulse/Analog linearity current?
> Guy Reggio
> Senior Analytical Chemist/Atomic Spectroscopy
> 14395 Bergen Blvd.
> Noblesville, IN 46060
> Ph: 317-674-9031
> [log in to unmask]
> -----Original Message-----
> From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). <
> [log in to unmask]> On Behalf Of Michael Szoltysik
> Sent: Wednesday, May 16, 2018 2:07 AM
> To: [log in to unmask]
> Subject: Silver issue, Agilent 7700/7900
> Dear PlasmaChemists,
> I have an issue with silver on some of my Agilent 7700 and 7900
> instruments. My calibration curve and recoveries on my QCs gottten
> progressivly worse over time. Calibration curve (done on a custom
> multistandard, 4% HNO3, 1 %HCl) is more or less quadratic now, instead of
> linear before, recoveries on my QCs are ranging between 30-50 %. This
> problem has gotten progressivly worse over time, just on certain
> instruments (i couldn't find any correlation on what matrices are ran on
> those certain instruments). I've tested following: followed Agilent's
> advice to do a clean-up of the front end of the instrument (3 different
> solutions followed by a nitric acid wash), changed the entire front-end
> including sample intake, lenses even the octapole, tested with just a
> single element solution with different acid concentrations ranging from 1%
> HCl - 20 % HCl, different wash out solutions and timings. All
> solution/different acids testing has been done with and without
> autosampler, as well as with self aspiration. My conclusion was, based on
> real time monitor, that silver has much longer stabilisation and wash out
> time (regardless the acid conc) than the other elements on the instruments
> with this problem. Apart from that, the issue dissapears temporarly after
> changing vacuum pump (not oil only, but the entire vacuum pump). The same
> calibration solutions, QCs are working fine on other instruments (both
> Agilents and PE instruments) which rules out the solutions. Increasing
> timings is not a favourable thing, due to high sample volumes. I'm in a bit
> lost for ideas on what it might be and was hoping to get some insights, did
> anybody have a similar issue?
> Thanks in advance!
> Kind Regards
> Michael Szoltysik
> Eurofins Environment Testing Sweden AB
> Development Chemist & Team Leader
> Metal Dep.
> Phone: +46 10 490 8133
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