Organic and inorganic arsenic speciation through ion exchange chromatography with particle beam-glow discharge mass spectrometry detection

Abstract

A mixture of organic and inorganic arsenic compounds has been separated using ion exchange liquid chromatography and detected using a particle beam glow discharge mass spectrometer (PB-GDMS). The particle beam interface makes use of nebulization and momentum separation to deliver a stream of dry analyte particles to the glow discharge source from the LC output. In the glow discharge, the analyte particles are vaporized and ionized at or near the cathode surface. The ions are analyzed by a quadrupole mass spectrometer collecting data in either single ion monitoring (SIM) or total ion counting (TIC) modes. The separation of arsenobetaine (2-(trimethylarsonio)acetate), arsenic(III) chloride and dimethylarsenic acid was performed on a universal cation-exchange column using an isocratic mobile phase, with a total elution time of less than four minutes. The mass spectrum for each of these compounds contains a strong elemental arsenic signal as well as the molecular fragments that allow for the identification of the specific species responsible for the chromatographic peak. The limits of detection (LOD) for organic arsenic (dimethylarsenic acid) were found to be 2 ppm (90 ng DMA molecular ion) in the TIC mode and 15 ppb (0.8 ng As from DMA) in the SIM mode. Inorganic arsenic(III) chloride has an LOD of 11 ppb or 0.55 ng As absolute. This work suggests that the PB-GDMS has high potential as a comprehensive (inorganic/ organic) detector for both biological and environmental speciation work.

Analytical methods for sensing of health-hazardous arsenic from biotic and abiotic natural resources

“…Additionally, the technique should provide both the sensitivity of elemental analysis and molecular spectral information. In this regard, Venzie et al 88 utilized particle beam glow discharge mass spectrometry (PB-GDMS) as an instrumental method in order to meet the above mentioned requirements. In this study, the detection of both organic and inorganic arsenic compounds has been carried out using a modied mass spectrometer known as a particle beam-glow discharge mass spectrometer (PB-GDMS) aer their ion exchange liquid chromatography separation (Table 1).…”

“…It can be suggested from the work that PB-GDMS is a high potential comprehensive detector for both inorganic and organic arsenic detection and is mainly compatible as an arsenic speciation detector providing both atomic and molecular information in the spectra for arsenic detection. 88 Among various mass spectrometry methods, electrospray mass spectrometry (ESMS) or tandem mass spectrometry (MS/MS) has been accepted as a very sensitive and selective on-line detector for the detection of almost 50 arsenic species. This technique has been found to be more efficient for arsenic detection as a consequence of the structural diversity in arsenic species as compared to the predominantly applied high performance liquid chromatography (HPLC) on-line with inductively coupled plasma mass spectrometry (ICPMS).…”

Plasma-based mass spectrometry for simultaneous acquisition of elemental and molecular information

“…31 This system was also applied to environmental speciation analysis. For example, a mixture of organic and inorganic arsenic compounds has been successfully separated with ion exchange LC and detected using PB-GD-MS. 32 The mass spectrum for each of these compounds contains a strong elemental arsenic signal as well as the molecular fragments that allow for the identification of the specific species responsible for the observed chromatographic peak. Therefore, the PB-GD-MS seems to hold high potential as a comprehensive (organic and inorganic) detector for both biological and environmental speciation work.…”

Selenium speciation by liquid chromatography-particle beam/mass spectrometry (LC-PB/MS): application to a yeast reference material and synthetic urine

“…Previous work in this laboratory involved the liquid chromatography particle beam mass spectrometry (LC-PB/MS) system for the analysis of a large number of organic, inorganic, organometallic and biological compounds in neat solutions and real world samples such as botanical products (e.g., green tea, echinacea, kelp) using interchangeable ionization sources (electron ionization and glow discharge). 23,24,26,[29][30][31] The PB interface treats analytes in a GC-style by converting them into the gas phase prior to ionization. The primary quality of this approach is that typical LC eluents (meaning ow rate, composition and polarities) are directed to low pressure (<10 À3 Torr) ionization sources without any remnants of the LC solvents.…”

“…the identication and quantication of individual elemental and molecular species), which are necessary for metabolic studies, regulatory compliance and quality control. 23,24,26,29 Consequently, as part of the ongoing method validation, which includes the expansion of the numbers of botanical/dietary supplements and the evaluation of more complex matrices via LC-PB/MS, the present work focuses on the separation and identication of organic and inorganic Se species in a Se-enriched yeast certied reference material (SELM-1) and a synthetic urine sample. The SELM-1 is a reference material introduced by the National Research Council Canada that has been certied for the methionine (Met), SeMet and total Se content.…”