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:

Hamilton Syringe Care and Use Guide

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).

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

On the subject of cleaning syringes, I've found that phosphoric acid (any acid, presumably) is great for rejuvenating 10uL syringes that seize up with brown crud after many water injections.

Paul Eby
Alberta Research Council

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July-August 2009

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December 2008

SIL co-director Christina Ravelo (Ocean Sciences) gives the 2008 Emiliani Lecture at the American Geophysical Union Meeting in San Francisco on "Lessons from the Pliocene Warm Period and the Onset of Northern Hemisphere Glaciation".

September 2008:

UCSC SIL has been funded by the National Science Foundation for a new Dual-Inlet Isotope Ratio Mass Spectrometer with individual acid drip system for very small calcium carbonate samples.

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