A CE/ESI-MS interface for stable, low-flow operation.
A rugged, stable liquid sheath interfacing procedure for on-line CE/MS is described. This procedure combines optimized component sizes, tapered capillary tips, and adjustment of the capillary with respect to the liquid sheath tube during electrospray operation (active capillary positioning) to establish a stable electrospray quickly and reliably. The interface is especially effective at low flow rates, and CE/MS with a liquid sheath flow rate of 250 nL/min has been achieved. Active capillary positioning also allows on-line capillary isoelectric focusing mass spectrometry with in-probe focusing. In this application, the capillary is retreated into the liquid sheath tube, which becomes a microreservoir. After focusing, the capillary is returned to its proper position for electrospray, and focused zones are mobilized into the mass spectrometer for on-line detection. Both active capillary positioning and in-probe focusing readily lend themselves to automation.
Kirby
D P
DP
Bamett Institute, Boston, Massachusetts, USA. dankirby@ma.ultranet.com
Thorne
J M
JM
Götzinger
W K
WK
Karger
B L
BL
D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006454:Hemoglobins / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods*
D006454:Hemoglobins