Interface for Capillary Electrophoresis and Inductively Coupled Plasma Mass Spectrometry

Abstract

A modified concentric glass nebulizer interface for capillary electrophoresis (CE) and inductively coupled plasma mass spectrometry is described. A conductive liquid coaxial sheath in the nebulizer was used as the return ground for the CE capillary. The variable position of the CE capillary in the nebulizer interface made a compromise between separation resolution and signal intensity possible. Negative reservoir pressure was applied to counterbalance nebulizer suction to the CE capillary and restore resolution. Metallothionein and ferritin were evaluated to characterize the interface. Metallothionein isoforms and ferritin were separated and their metal contents identified. Detection limits achieved for 57Fe and 114Cd in ferritin were 184 and 4.0 fg, respectively, for 74 nL injections.Capillary electrophoresis (CE) is applied for the separation of small inorganic1-7 and organic ions,89 small drug molecules,10 peptides,11-14 and proteins.15-18 CE generally offers better resolution and separation efficiency than chromatographic techniques, and the separation is usually faster and requires much less sample (a few nanoliters).Since Smith et al.19 first developed capillary electrophoresismass spectrometry (CE-MS), CE-MS has been extended to almost all kinds of CE techniques.20-23 In most cases, electrospray(1) Jandik, P.;

Sample introduction systems for the analysis of liquid microsamples by ICP-AES and ICP-MS

“…A sheathing electrolyte flow was able to eliminate the laminar flow in the electrophoresis capillary. In other work, Lu et al [118] used an interface in which the nebulizer CZE capillary position could be varied and the Eliminado: Figure 9 electrical connection was achieved with an electrolyte solution. They also improved the separation by applying a negative pressure at the sample inlet to compensate for the nebulizer suction effect.…”

Detection and identification of rabbit liver metallothionein-2 subisoforms by capillary zone electrophoresis - inductively coupled plasma mass spectrometry and microbore HPLC - electrospray mass spectrometry

“…It was mounted on the standard Scott spray chamber. The concept was similar to that described by Lu et al [10] The capillary was threaded through the colinear end of a T-piece; on the exit end it was inserted into a stainless steel tube and further sheathed with Teflon tubing to the base of the nebulizer. The capillary was inserted into the central tube of the nebulizer.…”

“…The principal reasons include the appearance of the laminar flow through the capillary as a result of the nebulizer suction and the need (unless a sheathless interface is used) for a makeup flow at the level exceeding 10 -100 times the electroosmotic flow to establish the electrical contact and to assure the optimum nebulization [10][11][12].…”

Eletroforese capilar acoplada à espectrometria com plasma: uma ferramenta eficiente para a especiação

“…Um recurso utilizado para implementar a interface CE-ICP-MS é a introdução do capilar no interior do nebulizador. Vários tipos de interface, feitas nos próprios laboratórios de pesquisa, empregando nebulizadores concêntricos [26][27][28][29][30] e micro-concêntrico [31][32][33][34] , de injeção direta 35 (DIN: Direct Injection Nebulizer), dealta eficiência 27 (HEN: High Efficient Nebulizer) e ultra sônico 36 , têm sido propostos. Dentre esses, o HEN é o mais adequado para as micro-amostragens necessárias para os acoplamentos com HPLC, CE e FIA (FIA: Flow Injection Analysis) ou mesmo para conseguir maior freqüência analítica.…”