Elimination of chloride interference on arsenic speciation in ion chromatography inductively coupled mass spectrometry using an octopole collision/reaction system

• Published in: Microchemical journal Vol. 87; no. 1; pp. 87 - 90
• Main Authors: Chen, ZuLiang, Khan, Nasreen Islam, Owens, Gary, Naidu, Ravendra
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2007
• Subjects: Arsenic speciation; Collision/reaction cell; Groundwater; IC–ICP-MS; Arsenic speciation; IC–ICP-MS; Groundwater; Collision/reaction cell
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2007.05.011

Anion-exchange chromatography with inductively coupled plasma mass spectrometry (ICP-MS) is often used for the speciation of arsenic (As). In this work, either He or H
2 was introduced to the octopole collision/reaction cell to eliminate chloride (Cl
−) interferences during As speciation by ICP-MS. Polyatomic species,
40Ar
35Cl and
38Ar
37Cl, which are formed in high chloride matrices interfere with the ICP-MS detection of
75As. These interferences were reduced or eliminated by introducing He or H
2 to the collision/reaction cell, with some loss in sensitivity when compared to the standard mode (no gas). For example, the sensitivity of As(V) was 30.4 and 17.7% of that observed in standard mode when introducing He and H
2, respectively. Chloride interference was completely eliminated using a flow rate of 3.0 mL min
−
1
with H
2 as a reaction gas with detection limits in the range of 0.3–0.6 μg L
−
1
. The developed method was applied to determination of arsenic species in waters containing high concentrations of chloride by following a simple procedure and without modification of the ICP-MS instrument.