Evaluation of a microconcentric nebulizer and its suction effect in a capillary electrophoresis interface with inductively coupled plasma mass spectrometry
C. B'Hymer et al., Evaluation of a microconcentric nebulizer and its suction effect in a capillary electrophoresis interface with inductively coupled plasma mass spectrometry, APPL SPECTR, 54(7), 2000, pp. 1040-1046
An experimental consideration and common difficulty when interfacing capill
ary electrophoresis (CE) with plasma mass spectrometry via a pneumatic nebu
lizer is the suction effect caused by the natural aspiration of the nebuliz
er. This is a significant effect in terms of the CE experiment, since it ca
n seriously degrade the separation of analytes, In this study, a pneumatic
microconcentric nebulizer was studied as a CE interface with inductively co
upled plasma mass spectrometry (ICP-MS). A self-aspirating sheath flow inte
rface technique was used to reduce the suction effect of the nebulizer by u
sing a separation of metallothionein I and ferritin. However, the sheath fl
ow or make-up buffer technique has not been studied sufficiently with respe
ct to all the effects on the CE analysis. In this evaluation, a sol-gel fri
t was plated in the sample introduction end in this CE system, and the cont
ribution of the suction effect to both sample response from sample loading
and elution times was observed. It was found that the studied microconcentr
ic nebulizer could be used effectively with the self-aspirating sheath flow
technique; however, the contribution of the suction effect to sample loadi
ng to the CE system is very high. The peak area response difference of an o
pen capillary vs, a sol-gel fritted capillary was approximately one order o
f magnitude greater. Also, the fritted capillary experiments showed that th
e contribution to migration time from aspiration of the nebulizer through t
he CE capillary is very significant.