Hi all,

We had some
discussion about the LGR DLT-100 syringe at this years Continuous Flow
conference. Since returning I believe I have made a bit of progress (at
least for our instrument) that might be useful to other LGR DLT-100
users. I called Hamilton asking about the 1.2 uL syringe (p/n
203185/01) recommended for the LGR liquid water instrument. They sent
me a care and maintenance pdf and a precision and accuracy statement
pdf. Those are posted here:

http://depts.washington.edu/isolab/IsoGeoChem/

Note the tiny differences in injection volume that the LGR picks up
that we are concerned about are well below any precision specs that
Hamilton claims. Also, we have quite a pile of "old" syringes that once
gave good injection volumes. According to Hamilton, these syringes are
serviceable. They recommend an alcohol rinse. I have made bad syringes
start working again by doing the following with a method created for
the PAL autosampler:

1) rinse 10 times with reagent grade acetone using a reasonably SLOW plunger motion
2) rinse 10 times with reagent grade methanol or ethanol (they both
have worked...even the alcohol mix has worked), again, with a very slow
plunger motion
3) rinse 10 times with DI water (ok we use 18 M ohm, but DI should be fine)
4) in a separate PAL method, we then do 300 actuations of the plunger
with the syringe in DI water, here again, with SLOW plunger motion

After doing 1 through 4 , it takes 2-3 injections for the H2O_cm_3 to
return to 3.2*10^16 but then it usually stays there. In addition to
this process, we do #4 (above) if the instrument has sat idle for more
than a few hours and we start and end each run with a vial of 18 M ohm
water. Note, all of this assumes the rest of the instrument is
functioning properly (pump, new septum, fresh reagents, etc etc).


andy
 Andrew Schauer
Earth and Space Sciences
University of Washington
Seattle, WA 98195


206.543.6327
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http://depts.washington.edu/isolab/