Speciation with ICP

Liquid chromatography (LC) is the most commonly used technique for trace element speciation with ICP-MS detection. The mobile phase flow rates used with most LC techniques (0.5-2.0 mL min-1) are compatible for ICP-MS introduction using conventional sample introduction systems (pneumatic nebulization with cross flow and concentric nebulizers and double-pass spray chambers). An interface, known as a transfer line, must be constructed to allow connection between the outlet of the LC column and the nebulizer of the ICP-MS. Inert plastic tubing is commonly used for this purpose with the inner diameter and length kept to 20-50 cm in order to minimize peak broadening. 

Relatively few authors have reported the use of this instrumentation for detection in speciation analysis so far. Only five elements (Se, S, Cr, V, As) have been the focus of research papers, and of these, selenium has received the most attention. Very recently, attempts have been undertaken to establish iron speciation with ICP-CC-MS detection. 

For chromium speciation with ICP-DRC-MS analysis, ammonia was selected as the reaction gas. Airborne Cr(VI) was separated from Cr(III) using a silica gel determination of ultratrace quantities of Cr(VI) was possible using preconcentration via complexation and ICP-DRC-MS. For aqueous samples, ion pair reversed phase HPLC was applied. ... 

---