We have purchased two different nano-spray attachments. Originally, we
purchased the Protana device (www.protana.com). This device allows the most
flexibility in terms of positioning the spray tip etc. It has a 3-d stage and
you can buy the cameras and monitors so you can exactly position the tip where
you want it. A setup like this will set you back 10-12 k. We like to use the
New Objective (www.newobjective.com) pico tips. For us, it is more convenient
to buy the tips instead of pulling our own. The pico tips are made of fused
silica and are very convenient to use for either direct infusion or nano-LC.
Since we've been using the pico tips, we have not found the positioning of the
tip that critical. If you get the tip within 5 mm of the heated capillary
it's fine. If you're not that concerned with positioning of the tip, you can
buy an adapter for your TSQ/LCQ that converts the needle assembly into a
device where you can mount a pico tip. I've recently purchased one of these
and found it to work quite well. You can pick one of these up for <1k from
New Objective. You might find it a good place to start, instead of shelling
out the 10-12 k for the full blown Protana setup. If you're one that likes to
eak out the last 10% increase in ion current, get the Protana device. There
are lots of options on the tips, e.g., gold coated tips, uncoated tips, distal
coated tips, etc. The coating is probably the first thing that will fail. We
are now leaning toward uncoated tips and applying the voltage to the metal
union and liquid junction between the transfer line and pico tip. We think
this makes for a fairly rugged setup. We like the 360 um od, 50 um id, 8um
tip pico tips. We think this represents a good tradeoff between flow rate and
potential for clogging. A third alternative is just to set up a stainless
steel needle. We have found that a 35 gauge hypodermic tube
(www.smallparts.com) substituted for the normal fused silica needle in the
finnigan probe will get you down to 200 nL/min. The metal needel does not
spray 100% water nearly as well as the true nano spray device. However, unless
we're really sample limited, this is our "default configuration". With a 35
ga. tube you can flow 200 nL/min - 200 uL/min through it, which makes it very
convenient for general purpose use. We had to do a little "engineering" of
this setup to prevent people from getting stung by the HV, but it's pretty
simple. I can provide details if you're interested. Good luck.
Mark Hail
Bristol-Myers Squibb
_______________________________________________________________________________
From: Tim Slattery on Wed, Sep 9, 1998 2:21 PM
Subject: Nanospray on the LCQ
To: Recipients of ABRF List
I've had my LCQ for a year now, and would like to start working with
nanospray. At this point I have no experience and little information
about setting up a nano-electrospray system. If anyone could give me
the answers to a few questions, and maybe more importantly answer the
questions I don't have the experience to ask yet...
Does anyone make a commercial nano-electrospray attachment?
If you built one, were there any key references you used, or what are
the key points a first timer is likely to miss.
Do you buy tips, or pull your own?
What kind of flow rates and spray voltages do you use?
Do you put the tip into the heated capillary, or just keep a little
separation?
Thank you for any answers you can give.
--tks
Tim Slattery
Protein Biochemistry and Biophysics Department
Berlex Biosciences
tim_slattery@berlex.com
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From: Tim Slattery <Tim_Slattery@berlex.com>
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