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

Abstract

Inductively coupled plasma mass spectrometry Simple and high efficient interface a b s t r a c tIn this work, a capillary electrophoresis (CE) coupled with inductively coupled plasma mass spectrometer (ICP-MS) system was developed for the simultaneous determination of ten arsenic compounds including arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine, 3-nitro-4-hydroxyphenylarsonic acid, o-Arsanilic acid, p-ureidophenylarsonic acid, and 4-nitrophenylarsonic acid. The CE-ICP-MS system was hyphenated by a novel and high efficient interface which was directly used as the nebulizer. The separation was achieved on a 100 cm length × 50 m ID fused-silica capillary. Analytical conditions such as electrophoretic buffer composition, concentration and pH value, separation voltage, methanol concentration in the sheath flow liquid and sample injection time were optimized. Baseline separation of the ten arsenic species was achieved using an electrophoretic buffer consisting of 12 mM NaH 2 PO 4 and 8 mM HBO 3 at pH 9.20 with an applied voltage of +30 kV. The detection limits of the ten arsenic compounds ranged from 0.9 to 3.0 ng As g −1 , corresponding to absolute detection limits in the range of 19-65 fg As and the relative standard deviations (RSD, n = 5) were below 1.5%, 5.7% and 4.8% for migration time, peak height and peak area, respectively. This method was successfully applied to determine various arsenicals in two certified reference materials (TORT-2 and DORM-3) and environmental samples such as ground water samples, herbal plants and chicken meat.

Efficient Interface for Online Coupling of Capillary Electrophoresis with Inductively Coupled Plasma–Mass Spectrometry and Its Application in Simultaneous Speciation Analysis of Arsenic and Selenium

“…The CE separation of arsenic and selenium compounds was affected by several operation parameters, such as chemical components, concentration and pH of buffer solution, and the separation voltage. In our previous work, 19 the best resolution and lower retention time for arsenic speciation were obtained when the mixture of phosphate and borate were used as the electrophoretic buffer. This buffer system has been examined in this experiment and the composition of electrolyte buffer was optimized for the simultaneous speciation of arsenic and selenium.…”

“…In this work, a CE-ESI-MS sprayer was used as the injection nebulizer to couple CE with ICP-MS, as described in the previous work. 19 The sprayer interface could eliminate the liquid dead volume of the CE-ICP-MS system, offer high sample introduction efficiency, and simultaneously maintain high CE resolution. With the use of the proposed interface ( Figure 2B), the migration times and the peak width of arsenic species decreased, resulting in peak sharpening and higher separation efficiency compared with the use of the commercial MicroMist nebulizer (Figure 2A).…”

“…The interface used in this work was configured on the basis of our previous work, 19 and the schematic diagram was illustrated in Figure 1. Briefly, a CE-ESI-MS sprayer (G1607A, Agilent Technologies, USA) was used as the interface for coupling CE with ICP-MS as well as the nebulizer for the ICP-MS.…”

Inorganic Arsenic Determination in Food: A Review of Analytical Proposals and Quality Assessment Over the Last Six Years

“…Several As species have been reported in this material, with AB being the major species and DMA, MA, and TMAO minor components. 243,256 Thirty-four published iAs contents 137,163,202,217,243,256,259,276,277 are tabulated and shown in Figure 6. The dataset includes an outlier: 4.46 mg As kg…”

“…Niegel et al 216 develop a method based on CE coupled to electrospray ionization time-of-flight mass spectrometry (CE-ESI-TOF-MS) for arsenic speciation, with application to the analysis of some algae extracts; although no results for iAs compounds are obtained. Liu et al 217 propose a novel interface (the commercial CE-ESI-MS sprayer kit) for CE-ICP-MS, and apply it to arsenic speciation in the CRMs TORT-2 and DORM-3, as well as to herbal plants and chicken meat, the results from which include iAs compounds. More recently, Qu et al 218 develop a method for arsenic speciation in rice and cereals.…”