Indo. J. Chem., 2006, 6 (2), 155 - 160 Ganden Supriyanto & Jurgen Simon 155 * Corresponding author. Phone/ Fax +62-31- 5922427 Email address : ganden@unair.ac.id (G. Supriyanto) A NOVEL METHOD OF THE HYDRIDE SEPARATION FOR THE DETERMINATION OF ARSENIC AND ANTIMONY BY AAS Ganden Supriyanto a,* , and Jürgen Simon b a Department of Chemistry, Airlangga University Surabaya, Kampus C Unair, Jl. Mulyorejo Surabaya Indonesia b Institute of Chemistry, Free University of Berlin, Fabeckstrasse 34-36, 14195 Berlin Germany Received 9 March 2006; Accepted 1 June 2006 ABSTRACT A novel method is proposed for the hydride separation when determinining of arsenic and antimony by AAS. A chromatomembrane cell was used as preconcentration-, extraction- and separation-manifold instead of the U-tube phase separator, which is normally fitted in continuous flow vapour systems generating conventionaly the hydrides. The absorbances of the hydrides produced were measured by an atomic absorption spectrophotometer at 193.7 nm and 217.6 nm. Under optimized analytical conditions, the calibration plot for arsenic was linear from 50 to 500 ng.mL -1 (r 2 = 0.9982). The precision for three subsequent measurements of 500 ng.mL -1 arsenic gave rise to a relative standard deviation of 0.4%. The detection limit was 15 ng.mL -1 , which is much lower compared with that of the conventional hydride system (2000 ng.mL -1 ). A similar result was observed in case of antimony: the detection limit was 8 ng.mL -1 when the proposed method was applied. Consequently, the sensitivity of the novel method surpasses systems with conventional hydride generation, i.e. the precision and the acuracy increase whereas the standard deviation and the detection limit decrease. The proposed method was applied in pharmacheutial analysis and the certified As-content of a commercial product was very sufficiently confirmed. Keywords: Chromatomembrane Cell, Hydride separation, Arsenic detection, Antimony detection, AAS INTRODUCTION The role of arsenic as a toxic element is well investigated. Evidence has been presented that low levels of arsenic may be easily tolerated from the human body, whereas higher concentrations are toxic. The pathological effects of oral exposure include particularly cardiovascular, dermatological, haematological, hepatic and renal illness. Arsenic can also cause cancer of the genial and urinary apparatus, the respiratory system and the skin [1]. Because of its toxicity and cumulative effect in the body, arsenic presents a health problem when it occurs in food, water and environment, even in minute amounts. In contrary, very little attention has been paid to antimony, mainly because it is not recognized as having nutritional significance and its contents in most materials are very low. Nevertheless, compounds of antimony are moderately toxic to most organisms, Sb(III) compounds being more toxic than that of Sb(V) compounds (similarly to the corresponding arsenic compounds). Exposure to antimony causes cellular damages in the lungs, heart and kidneys but the toxicity mechanisms are still not well known [2]. A number of sensitive analytical methods are available for the determination of arsenic and antimony. Some of the commonly used methods are anodic stripping voltammetry, inductively coupled plasma atomic emission spectrometry (ICP-AES), graphite-furnace atomic absorption spectrometry (GFAAS), electrothermal atomic absorption spectrometry (ETAAS), neutron activation analysis, and hydride generation atomic absorption spectrometry (HGAAS) [3]. Hydride generation coupled with atomic absorption spectroscopy (AAS) has become one of the most powerful and well-established techniques for the determination of arsenic and antimony. Hydride generation techniques offer unique advantages including elimination of the nebulizer need on enhancement of analyte transport efficiency (approaching 100%), reduction of matrix effects and the presentation of a homogeneous vapour to the atomizer [4]. A variety of reactions have been used to convert the analyte in solution in to the hydride. Huge numbers of publications [5-9] regarding the determination of arsenic and antimony by hydride generation coupled with AAS have been published in environmental and biological field. The separation of the generated hydride from the liquid phase is important in order to ensure appropriate transfer of the analyte to the atomizer. This is provided by gas-liquid separators and the most common type is aU-tube. Many other designs have been made to improve the hydride separation. A packed U-tube, a cooled U-tube, a porous tube and a stripping–type gas- liquid reactor separator have been proposed because