|Yanes Santos, Enrique|
Submitted to: Spectrochimica Acta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/18/2004
Publication Date: 6/18/2004
Citation: Yanes Santos, E.G., Miller-Ihli, N.J. 2004. Use of a parallel path nebulizer for capillary-based microseparation techniques coupled with an inductively coupled plasma mass spectrometer for speciation measurements. Spectrochimica Acta. 59:883-890 Interpretive Summary: This research is directed at combining microseparation techniques with inductively coupled plasma mass spectrometry (ICP-MS) for speciation determinations. Microseparation techniques such as capillary electrophoresis (CE) and micro high performance liquid chromatography (µHPLC) offer the advantage of small solvent volume and sample volume requirements. We have demonstrated for the first time that gradients using organic solvents (e.g. methanol) may be used successfully without concern of transient effects and have highlighted the increased sensitivity obtained when using methanol for the make-up solution with these capillary techniques. We are also the first to evaluate and report on the use of a Mira Mist CE parallel path nebulizer for use with CE-ICP-MS and µHPLC-ICP-MS. Cobalamin (Vitamin B12) species were separated using both techniques with CE-ICP-MS providing the best sensitivity. This work will be of interest to others working in the field of speciation determinations interested in interfacing microseparation techniques with ICP-MS.
Technical Abstract: A low flow, parallel path Mira Mist CE nebulizer designed for Capillary Electrophoresis was evaluated as a function of make-up solution flow rate, composition, and concentration, as well as the nebulizer gas flow rate. This research was conducted in support of a project related to the separation and quantification of cobalamin (Vitamin B-12) species. As such, Co signals were monitored during the nebulizer characterization process. Transient effects were studied to evaluate the suitability of using gradients for microseparations and the benefit of using methanol for the make-up solution was demonstrated. Maximum signal enhancement was seen at 20% methanol with a 15 µL/min flow rate. Evaluation of the effect of changing the nebulizer gas flow rates showed that argon flows from 0.8 to 1.2 L/min were equally effective. The Mira Mist CE nebulizer was then evaluated for interfacing capillary microseparation techniques including capillary electrophoresis (CE) and micro high performance liquid chromatography (µHPLC) to inductively coupled plasma mass spectrometry (ICP-MS). A mixture of four cobalamin species standards (cyanocobalamin, hydroxocobalamin, methylcobalamin, and 5' deoxyadenosylcobalamin) and the corrinoid analogue cobinamide dicyanide were successfully separated using both CE-ICP-MS and µHPLC-ICP-MS using the parallel path nebulizer.