Derek,
We routinely use Protana "medium" tips for the same type of samples you do.
With one caveat, I have had good luck with opening them and with keeping
them spraying; in instances where the tip stops spraying, my experience has
been that the problem is usually with the sample. The caveat is that we
received a batch of 200 of these tips in late December, all from the same
batch, and approximately 80% of them would not open properly. Protana
immediately exchanged these for 200 new tips from another batch and these
have worked without difficulty. This was the first bad batch we have
encountered in about 15 months of using nanospray -- probably 600-700 tips
in total. FWIW, we use these tips in a "new design" Protana source mounted
on a QSTAR. Also, we clean all tryptic digest samples using the POROS spin
microcolumn method detailed on Protana's web site
(http://www.protana.com/products/applicationnotes/purification/default.asp).
New Objective (www.newobjective.com) in Cambridge, Massachusetts is another
supplier of tips intended for nanospray. Their tips differ from the
traditional pulled capillary in that they have a pre-formed orifice of
defined diameter instead of the glass "whisker". Thus, their tips do not
need to be opened before use. I have never used their nanospray tips, but I
have occasionally used their microspray tips for online capillary LC/MS. In
this application I have found it rather too easy to burn off the conductive
coating at the tip of the orifice, giving an erratic spray if the damage
goes unnoticed. This is probably the result of my inexperience with these
tips and would likely be resolved by more familiarity with proper operating
conditions. I can't say if the same problem might occur with the nanospray
tips. Finally, last time I checked, the New Objective tips were somewhat
more expensive than the Protana tips.
Good luck in your search,
Roger
Roger Mercer - rsmercer@ucdavis.edu (http://msf.ucdavis.edu)
Mass Spec Specialist UC Davis Molecular Structure Facility
====
When asked why he had left the Northeast and moved to California,
the scientist replied, "When I was 20, I wanted to be a lover. When
I was 30, I wanted to be rich. Now I just want to be warm."
-----Original Message-----
From: Association of Biomolecular Resource Facilities
[mailto:abrf-request@aecom.yu.edu]On Behalf Of Derek Bradley
Sent: Wednesday, February 07, 2001 1:38 AM
To: Recipients of ABRF List
Subject: MS: Nanospray Needles
Hi Guys,
Does anyone know of any suppliers of nanospray needles other than Protana?
I've been using theirs up until now but find them unpredictable in how
easily they open and stay spraying and would like to try other sources for
the comparison. If anyone has any tips I'm generally spraying tryptic
digest/protein solutions using 50:50 MeOH:1% acetic acid.
Thanks,
Derek Bradley
Dept. of Medicine
UCL
London
This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 13:03:34 EST