Journal of Chromatography A, 1024 (2004) 105–113 Simultaneous determination of twelve inorganic and organic arsenic compounds by liquid chromatography–ultraviolet irradiation–hydride generation atomic fluorescence spectrometry Stéphane Simon, Huong Tran, Florence Pannier ∗ , Martine Potin-Gautier Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Université de Pau et des Pays de l’Adour, UMR 5034, Pau 64000, France Received 10 March 2003; received in revised form 25 September 2003; accepted 26 September 2003 Abstract A coupling between column liquid chromatography (LC) and atomic fluorescence spectrometry was developed for arsenic speciation. After separation, the compounds are oxidised on-line by UV irradiation, volatilised by hydride-generation and carried to the detector by a stream of argon. A combination of anion-exchange and hydrophobic interactions in a single column (Dionex AS7) was found suitable for the simultaneous separation of organic and inorganic species. Twelve compounds (arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, tetramethylarsonium ion and four arsenosugars) were separated using an acetate buffer and a nitric acid solution as mobile phases. Limits of detection are 4–22 pg. The technique was applied to three marine samples. Arsenobetaine was detected as the main species in all samples, with concentrations varying from 59 to 1947 ng(As) g -1 of fresh mass. © 2003 Elsevier B.V. All rights reserved. Keywords: Marine samples; Speciation; Atomic fluorescence spectrometry; Arsenic 1. Introduction Arsenic is widely known as a toxic element and is natu- rally present in all environmental compartments in various forms, depending on the nature of the sample. Inorganic species are predominant in water and soil, whereas organic compounds are mainly present in living organisms. Many methods have been developed for the speciation of inorganic and methylated species, using different separation and detection processes. Ion-exchange chromatography cou- pled to atomic spectrometry is most frequently used. In the last decades, the interest for atomic fluorescence spectrome- try (AFS) as an element-specific detector has increased, be- cause of its low cost and ease of use. Recently, this detector has even been shown to be as efficient as inductively cou- pled plasma mass spectrometry (ICP-MS), as regards sen- sitivity and repeatability [1]. The interface between column liquid chromatography (LC) and AFS is hydride-generation, ∗ Corresponding author. E-mail address: florence.pannier@univ-pau.fr (F. Pannier). which allows a quantitative sample introduction and has the advantage of removing many matrix interferences. However, this approach is limited to hydride-forming species, namely for arsenic: arsenite (As III ), arsenate (As V ), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA); therefore, organoarsenic compounds cannot be detected. Few authors have studied organoarsenic compounds de- tection with a hydride-generation-based interface. Almost always, species are first decomposed into hydride-forming compounds by reaction with an oxidant, using thermal [2,3], microwave [4–7] or UV irradiation [8–10] techniques. The last one is inexpensive and easy to use as no cooling system is required after decomposition. As regards LC separations reported in the literature, the most common modes are cation-exchange [3,11–18] and anion-exchange chromatography [4,5,9,16,19–21], reversed-phase chromatography [22,23] or a combination of these techniques [20,24,25]. Anion-exchange chromatography can separate inorganic and mono- and di-methylated species, which have an 0021-9673/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2003.09.068