PerkinElmer Discussion Forum / Radiometric Detection / Instrumentation

Karl Fischer

Ethanol — Thu, 09 Oct 2008 14:49:22 GMT

Can anyone here give me a clear and simple definition of what the drift is on the Karl Fischer? I work in an ethanol plant and am finding it difficult to explain what the drift is exactly.

Thank you very much

Wizard 2470 normalization for unknowns

Wizard WorkOut — Thu, 09 Oct 2008 13:54:04 GMT

What are the issues with normalizing an isotope with a differnent isotope?

for example using I-129 to normalize for I-131 or F-18

Is it just that the system wants to see any peak? Or is normalizing with a different isotope leading to problems with accurate quantification? If normalization provides a PMT gain adjustment, wouldn't the peak position be important?

Your thoughts?

Open Normalization

SWuser — Fri, 12 Sep 2008 09:54:22 GMT

Our 1480's hard drive crashed and we had to reinstall all software. As such, we have to reacquire all normalizations. Our problem is how to acquire an 'Open' isotope normalization. Initially, an open normalization does not make sense to me, but more importantly, how does one do it. I can make a rack, but we obviously dont have a 50-200kpm 'Open' source hanging around. Do we run the rack without a source, or do we grab any handy source? Any recommendations?

We use the 'Open' source definition primarily for wipe test, but do have a few other applications we want a large window.

Quench curve importation with Tricarb 2700

nmireault — Wed, 10 Sep 2008 16:46:40 GMT

How to import a quench curve with a Tricarb 2700 ?
We have the .DAT and output files (it has been constructed
with the same Tricarb but has been erased)

Difference between Tricarb 2700 and 3100

nmireault — Mon, 08 Sep 2008 14:19:11 GMT

The same samples (H3, C14 and H3/C14) are analyzed on both
a Tricarb 2700 and a Tricarb 3100.

The protocol is identical (same sample preparation, same counting time,
same quench indicator tSIE, and the same protocol to
construct the quench curves for H3 and C14).

Even if they have the same 3 regions configured
(CPM A : 0,5 - 12.5 keV associated to H3,
CPM B : 20 - 156 keV associated to C14
and CPM C : 156 - 2000 keV),
they don't yield the same CPM values...
I don't understand why.
Both Tricarb models measure about the same tSIE.

Especially in case
the samples have both H3 and C14, the
calculated H3 concentration can reach up to twice
the known value for the Tricarb 3100, while
the Tricarb 2700 succeed in its evaluation of
both H3 and C14 concentrations.

The Tricarb 2700 seem to use strange efficiency
for H3 (from 5% up to 75% while we should obtain around 45%
by looking on its H3 quench curve).
The Tricarb 3100 seems to really use the efficiency
we see on its quench curves.

Is there additional calculation/correction that the Tricarb 2700
performs ?

aquasol II

nmireault — Wed, 13 Aug 2008 13:16:40 GMT

The CPM A (region defined from 0.5 to 12.5 keV)
obtained from a C-14 water analysis in aquasol II
is varying a lot using a Tricarb 2700.

can reach up to 500 CPM
as usually it was kept under 30 CPM...

Protocol is using 6mL NaOH 0,4 N
with 15 mL Aquasol

That behavior has been first observed
during last year... has the formulation changed ???
Is there any new chemical that would interfere ?

quench curve ??

nmireault — Wed, 13 Aug 2008 13:10:11 GMT

using a Tricarb 3100, how is the quench curve (% efficiency vs tSIE) used for DPM assays
calculated ?

what is it's mathematical expression ?

how to get it's parameters from the software Quantasmart ?

Direct DPM feature on Tri-Carb be

68blucjp — Wed, 02 Jul 2008 14:18:56 GMT

Can the Direct DPM feature on the Tri-Carb be used for all radionculides.

Are there limitations of its use?

WIZARD

WIZUSER — Wed, 02 Jul 2008 14:15:49 GMT

Can I use WorkOut 2.5 with older Wizards 1470/1480?

MicroBeta use

MBuser — Wed, 02 Jul 2008 14:12:36 GMT

What cocktails should I use for counting filters? For counting in Microplates? What about MicroScint cocktails?

WIZARD GAMMA COUNTER

WIZUSER — Thu, 26 Jun 2008 13:45:03 GMT

In another thread, Nuc4U mentioned saving data with Uterm III. What is it and can I use it to save data files on my Wizard.

MicroBeta Use

MBuser — Wed, 25 Jun 2008 13:09:20 GMT

I am using several different isotopes and types of samples. How often do I need to normalize. And for what combinations of isotope and sample type.

Low level counting cocktail

WizardMcTriCarb — Mon, 30 Jun 2008 13:01:30 GMT

What would you recommend as a cocktail for counting ca 10DPM of C14. This is an animal tissue sample which I've solubilized using solvable

Wizard 1470/1480 User Questions

WIZUSER — Tue, 24 Jun 2008 13:13:40 GMT

How do I put in patient numbers or sample id's to be included in my data printout?

Heterogeneity monitor in TriCarb LSC´s

Ron — Tue, 03 Jun 2008 02:25:34 GMT

Recently I measured a few 14C samples and as usual I activated the heterogeneity monitor. After the measurement the software indicated an inhomogeneity in one of the samples. However, after inspection of the sample it was clear that the sample was homogeneous. Do you have an explanation?