Speciation analysis of arsenic and selenium compounds by CE‐dynamic reaction cell‐ICP‐MS

Abstract

A dynamic reaction cell ICP-MS was used as a CE detector for the speciation analysis of arsenic and selenium. Samples containing arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, selenite, selenate, selenocysteine, selenomethione, and Se-methylselenocysteine were subjected to electrophoretic separation before being introduced into the microconcentric nebulizer (CEI-100) for their determination by ICP-MS. The separation has been achieved in a 60 cm length x 75 microm id fused-silica capillary. The electrophoretic buffer used was 25 mmol/L CAPS, and 0.5 mmol/L SDS at pH 9.5, whereas the applied voltage was set at 25 kV. The potentially interfering (38)Ar(40)Ar(+) and (40)Ar(40)Ar(+) at the selenium masses m/z 78 and 80 were reduced in intensity by approximately three orders of magnitude by using 1.4 mL/min CH(4) as reactive cell gas in the dynamic reaction cell. Arsenic was determined as the adduct ion (75)As(12)CH(2) (+) at m/z 89. The LOD for arsenic and selenium was in the range of 0.6-1.8 ng/mL, and 0.5-1.4 ng/mL, respectively, based on peak height. This method has been applied to determine various arsenic and selenium compounds in NIST SRM 1633a Coal Fly Ash and NRCC DOLT-3 Dogfish Liver reference materials and a selenium dietary supplement. The arsenic and selenium compounds were extracted from fish liver and dietary supplement by using Protease XIV and Lipase, and from coal fly ash with HF solution. The spike recoveries were in the range 91-103% for all the species studied.

Speciation analysis of arsenic compounds by capillary electrophoresis on-line coupled with inductively coupled plasma mass spectrometry using a novel interface

“…The LODs for various arsenic species were in the range of 0.9-3.0 ng g −1 , corresponding to absolute detection limits in the range of 19-65 fg of As based on a 21.5 nL sample injection (Table 2). Compared to the other CE-ICP-MS methods [10,23,26,32,36], our method could simultaneously separate more arsenic compounds with higher separation efficiency than other methods. The detection limits were comparable or even better than those of the reported methods.…”

“…There are already some methods for the speciation of arsenic species by coupling high performance liquid chromatography (HPLC), gas chromatography (GC) and capillary electrophoresis (CE) with atomic fluorescence spectrometry (AFS), atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS) [3,[7][8][9][10][11][12][13][14][15]. GC has a great separation capacity for volatile arsenicals, but its application is limited because most naturally occurring arsenic species are non-volatile and have to be derivatized before further analysis.…”

Dynamic reaction cell ICP-MS for determination of total As, Cr, Se and V in complex matrices: Still a challenge? A review

“…The most common sample type injected in ICP-MS is liquid, although a wide range of techniques were developed for the introduction of solids and gases, as well [5]. In the last decade, the use of ICP-MS for biochemical applications is rapidly expanding; for instance, the level of trace metals incorporated in a cell can be quantified by coupling ICP-MS with high performance liquid chromatography (capillary and nanoflow HPLC) or electrophoresis (capillary and gel CE) [6,7].…”

Atomic spectrometry update. Elemental speciation

“…Detection of separated As and Se compounds down to 0.5 mg L À1 in extracts of coal fly ash, dogfish liver and dietary supplements by CE-ICP-MS has been achieved. 126 The potentially interfering argon dimers at the Se m/z values of 78 and 80 were decreased in intensity by approximately three orders of magnitude by reaction with methane in a DRC. Arsenic was determined as 75 As 12 C + at m/z 87.…”