Inorganic Arsenic Compounds Research Articles

Combined use of photocatalyst and adsorbent for the removal of inorganic arsenic(III) and organoarsenic compounds from aqueous media

A novel method for the removal of inorganic arsenic(III) (As(III)), monomethylarsonate (MMA), and dimethylarsinate (DMA) from aqueous media, was proposed and investigated. This method involves the combined use of TiO 2-photocatalyst and an adsorbent, which has a high ability of As(V) adsorption, under photo-irradiation. When an aqueous solution of As(III) was stirred and irradiated by sunlight or xenon lamp in the presence of TiO 2 suspension, the oxidation of As(III) into As(V) was effectively attained. By use of the same photocatalytic reaction, MMA and DMA were also degraded into As(V), while the total organic carbon (TOC) in the aqueous phase was decreased. When an aqueous solution of As(III) was stirred with a mixed suspension of TiO 2 and an adsorbent for As(V) (activated alumina) under sunlight irradiation, the arsenic removal reached 89% after 24 h. By use of the same photocatalyst–adsorbent system, 98% of MMA and 97% of DMA were removed. The mechanism of the removal of arsenic species by the photocatalyst–adsorbent system was discussed.

Inorganic Arsenic Compounds and Methylated Metabolites Induce Morphological Transformation in Two-Stage BALB/c 3T3 Cell Assay and Inhibit Metabolic Cooperation in V79 Cell Assay

We have performed two-stage transformation assay using BALB/c 3T3 cells to determine initiating and promoting activities of disodium arsenate, sodium arsenite, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). Treatment with these arsenic compounds at the initiating stage induced significant numbers of transformed foci when cells were post-treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). Disodium arsenate was active at the concentrations of 15-30 microM, sodium arsenite 5-20 microM, and DMAA 1-2 mM. MMAA required 10 mM to induce cell transformation. The concentrations of these compounds (except DMAA) that induced transformation were highly growth-inhibitory (more than 50%). DMAA induced transformation foci at growth inhibition levels of 66 to 84%. In experiments on promoting activity, cells pretreated with a sub-threshold dose of 20-methylcholanthrene (MCA, 0.2 microg/ml) or sodium arsenite (10 microM) were used. Transformation was enhanced by post-treatment with disodium arsenate (1-10 microM), sodium arsenite (0.5-2 microM), and MMAA (200-1000 microM), but not with DMAA. Studies of gap junctional intercellular communication using the V79 cell metabolic cooperation assay showed that the arsenic compounds (except DMAA) exhibited inhibitory activity. Thus, most arsenicals were shown to have not only initiating activity, but also promoting activity. In addition, inorganic arsenicals, especially trivalent sodium arsenite, were more active than organic ones and exhibited promoting activity at one-order of magnitude lower than initiating activity. These results suggest that from the viewpoint of human hazard, more attention should be paid to the tumor promoting activity of inorganic arsenic compounds.

Decomposition of organoarsenic compounds for total arsenic determination in marine organisms by the hydride generation technique

The conditions necessary for the complete decomposition of six organic arsenic compounds, namely methylarsonic acid (MMAA), dimethylarsinic acid (DMAA), trimethylarsine oxide, tetramethylarsonium iodide, arsenocholine bromide (AsC) and arsenobetaine (AB), were investigated. The degree of decomposition of the arsenic compounds was monitored using a hydride generation (HYD) technique, because the response from this system depends strongly on the chemical species of arsenic, with inorganic arsenic (the expected product from these decomposition experiments) giving a much more intense HYD signal than the organic arsenic compounds. The arsenic compounds were decomposed by heating them with three types of acid mixture, namely HNO3HClO4, HNO3HClO4HF, or HNO3HClO4H2SO4. Both MMAA and DMAA were decomposed completely using any of the mixed acids at a decomposition temperature of 200 °C or higher. The HNO3HClO4H2SO4 mixture was the most effective for decomposing AsC and AB, which are the most difficult compounds among all types of organic arsenic compound to decompose and render inorganic. The complete decomposition of AB was only achieved, however, when the temperature was 320 °C or higher, and the sample was evaporated to dryness. When the residue from this treatment was examined by high-performance liquid chromatography combined with inductively coupled plasma atomic emission spectrometry, all of the arsenic was found to be present as arsenic(V). The optimized conditions (HNO3HClO4H2SO4 at 320 °C) for decomposing AB were then used to determine the total amount of arsenic in marine organisms known to contain AB. Copyright © 2005 John Wiley & Sons, Ltd.

Current Perspectives in Arsenic Environmental and Biological Research

Environmental Context. Arsenic occurs in rock, fresh water and seawater. Organic arsenic compounds are found as natural constituents of many organisms and, because some, e.g. seafood, are consumed by humans, there is ongoing health interest in their arsenic content. Thio-arsenicals, a newly discovered group of arsenic compounds, may be integral to understanding the environmental behaviour of arsenic. This paper reviews recent research in arsenic environmental chemistry and discusses ideas intended to stimulate future research in this area. Abstract. Recent results in the field of arsenic environmental and biological chemistry are presented, in particular the relevance of the discoveries to issues of human health are discussed.

Detection of Bis(diphenylarsine)oxide, Diphenylarsinic Acid and Phenylarsonic Acid, Compounds Probably Derived from Chemical Warfare Agents, in Drinking Well Water

The inhabitants living in a specific region of Kizaki area in Kamisu-town, Ibaraki Prefecture exhibited uncommon clinical central nervous system symptoms. A graphite furnace atomic absorption spectrophotometer detected markedly elevated concentration of arsenic (4.5 ppm) in their drinking well water. Further investigation using HPLC, GC/MS and HPLC/ICP/MS demonstrated that the structures of the arsenic were bis(diphenylarsine)oxide (BDPAO), diphenylarsinic acid (DPAA) and phenylarsonic acid (PAA), compounds that can be derived from the chemical warfare agents, diphenylchloroarsine (DA) and diphenylcyanoarsine (DC). The predominant form of the arsenic compound in the well water was DPAA (maximum 15 ppm), so that it was calculated that the inhabitants ingested 11‐30 mg of DPAA daily. This is the first report of inhabitants that were injured by drinking well water contaminated with organic arsenic compounds that were likely derived from chemical weapons.

Environmental Contamination of Arsenic and its Toxicological Impact on Humans

Environmental Context. Tens of millions of people in developing countries are being exposed to excessive levels of arsenic in their drinking water, and this contamination is widely regarded as the largest current calamity of chemical poisoning in the world. However, arsenic can exist in many chemical forms, and these vary widely in solubility, toxicity, and in bioavailability. Therefore, it is critical to be able to measure arsenic speciation accurately and reliably in order to understand its toxicity and design effective measures of remedial action. Abstract. Inorganic arsenic compounds are known carcinogens. The human epidemiologic evidence of arsenic-induced skin, lung, and bladder cancers is strong. However, the evidence of arsenic carcinogenicity in animals is very limited. Lack of a suitable animal model until recent years has inhibited studies of the mechanism of arsenic carcinogenesis. The toxicity and bioavailability of arsenic depend on its solubility and chemical forms. Therefore, it is critical to be able to measure arsenic speciation accurately and reliably. However, speciation of arsenic in more complex matrices remains a real challenge. There are tens of millions of people who are being exposed to excessive levels of arsenic in the drinking water alone. The source of contamination is mainly of natural origin and the mass poisoning is occurring worldwide, particularly in developing countries. Chronic arsenicosis resulting in cancer and non-cancer diseases will impact significantly on the public health systems in their respective countries. Effective watershed management and remediation technologies in addition to medical treatment are urgently needed in order to avoid what has been regarded as the largest calamity of chemical poisoning in the world.

Determination of diphenylarsinic acid and phenylarsonic acid, the degradation products of organoarsenic chemical warfare agents, in well water by HPLC-ICP-MS

Diphenylarsinic acid (DPAA) and phenylarsonic acid (PAA), which were degradation products of organoarsenic chemical warfare agents used as sternutatory gas, were detected in the well water at Kamisu, Ibaraki Prefecture, Japan. The standard material of DPAA was synthesized with aqueous arsenic acid and phenylhydrazine in order to determine organic arsenic compounds in well water. The DPAA showed a protonated ion at m/z 263 [M + H]+ and a loss of H2O ion at m/z 245 [M + H − H2O]+ from protonated ion by the electrospray ionization time-of-flight mass spectrometry. The quantitative analysis of DPAA and PAA was performed by high-performance liquid chromatography inductively coupled plasma mass spectrometry and the system worked well for limpid liquid samples such as well water. Copyright © 2005 John Wiley & Sons, Ltd.

Effects of arsenobetaine, a major organic arsenic compound in seafood, on the maturation and functions of human peripheral blood monocytes, macrophages and dendritic cells

AbstractWe examine the in vitro immunotoxicity of synthetically pure arsenobetaine [AsBe; trimethyl (carboxymethyl) arsonium zwitterion], which is a major organic arsenic compound in seafood, on various human immune cells, such as peripheral blood monocytes, monocyte‐derived macrophages and monocyte‐derived dendritic cells (DCs). In particular, we examine the differentiation of monocytes into macrophages or DCs by comparing the effects of AsBe with those pentavalent inorganic arsenate. AsBe neither enhanced nor inhibited the differentiation of human monocytes into macrophages or DCs, and also did not affect their various immune functions. Furthermore, AsBe had no cytolethality in monocyte‐derived macrophages or DCs even at a concentration of 5 mmol l−1. In contrast, inorganic arsenate showed strong cytolethality in these human immune cells in vitro at micromolar concentrations. These data indicate that the organic arsenic compound AsBe in seafood has no in vitro immunotoxicity in human immune cells. Copyright © 2004 John Wiley & Sons, Ltd.

Phenylarsine Oxide (PAO) More Intensely Induces Apoptosis in Acute Promyelocytic Leukemia and As2O3-Resistant APL Cell Lines than As2O3 by Activating the Mitochondrial Pathway

We studied the cytotoxic effect of an organic arsenical compound, phenylarsine oxide (PAO) on an acute promyelocytic leukemia (APL) cell line (NB4) and an As2O3-resistant NB4 subline (NB4/As). Cell growth was inhibited by 50% (IC50) upon 2-day treatment with As2O3 or PAO at 0.54 and 0.06 μM, respectively in NB4 cells (P = 0.025), and 2.80 and 0.08 μM, respectively in NB4/As (P = 0.030). 0.1 μM PAO increased the proportion of hypodiploid cells (50.3%) by a greater degree than the same dose of As2O3 (3.8%) in NB4 cells. In NB4 cells, 0.1 μM PAO reduced the mitochondrial transmembrane potential (20.5% in a PInegative-Rhodamine123low fraction) by a greater degree than 1 μM As2O3 (7.1%). Western blotting showed that 0.1 μM PAO downregulated the expression of both Bcl-2 and Bcl-XL proteins, whereas I μM As2O3 downregulated only Bcl-2 expression. These results suggest that the cytotoxic effect of PAO on an APL cell line and As2O3-resistant subline is significantly higher than that of As2O3. PAO-induced apoptosis seems to be related to the activation of the mitochondrial pathway and downregulation of both Bcl-2 and Bcl-XL. PAO is a considerable agent for relapsed/refractory APL and for purging APL cells following stem cell transplantation.

Understanding arsenic carcinogenicity by the use of animal models

Although numerous epidemiological studies have indicated that human arsenic exposure is associated with increased incidences of bladder, liver, skin, and lung cancers, limited attempts have been made to understand mechanisms of carcinogenicity using animal models. Dimethylarsinic acid (DMA), an organic arsenic compound, is a major metabolite of ingested inorganic arsenics in mammals. Recent in vitro studies have proven DMA to be a potent clastogenic agent, capable of inducing DNA damage including double strand breaks and cross-link formation. In our attempts to clarify DMA carcinogenicity, we have recently shown carcinogenic effects of DMA and its related metabolites using various experimental protocols in rats and mice: (1) a multi-organ promotion bioassay in rats; (2) a two-stage promotion bioassay by DMA of rat urinary bladder and liver carcinogenesis; (3) a 2-year carcinogenicity test of DMA in rats; (4) studies on the effects of DMA on lung carcinogenesis in rats; (5) promotion of skin carcinogenesis by DMA in keratin (K6)/ornithine decarboxylase (ODC) transgenic mice; (6) carcinogenicity of DMA in p53(+/−) knockout and Mmh/8-OXOG-DNA glycolase (OGG1) mutant mice; (7) promoting effects of DMA and related organic arsenicals in rat liver; (8) promoting effects of DMA and related organic arsenicals in a rat multi-organ carcinogenesis test; and (9) 2-year carcinogenicity tests of monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO) in rats. The results revealed that the adverse effects of arsenic occurred either by promoting and initiating carcinogenesis. These data, as covered in the present review, suggest that several mechanisms may be involved in arsenic carcinogenesis.

Uptake and accumulation behaviour of angiosperms irrigated with solutions of different arsenic species

Uptake and metabolisation of arsenic as a function of both the plant type and the chemical form of arsenic were examined. For this purpose two different plant species ( Silene vulgaris and Plantago major) were selected that differed in their vitality and accumulation behaviour on arsenic-loaded substrates. The plants were cultivated on soil and irrigated with aqueous solutions of an inorganic arsenic compound (arsenious acid) and an organic compound (dimethylarsinate). The arsenic species accumulated in the parts of the plants above ground were extracted by PLE and determined using IC-ICP-MS. The concentrations and metabolisation products of arsenic found in the extracts indicate different mechanisms of arsenic uptake and transformation in both angiosperms. The arsenic species pattern showed that S. vulgaris was more arsenic––tolerable than P. major which is attributed to a low arsenate to arsenite concentration ratio in the plant compartments. S. vulgaris was also able to demethylate and reduce dimethylarsinate to form arsenite in a high extent. P. major accumulated only eight times lower concentration of arsenic, and the arsenate to arsenite concentration ratio shifted to higher values. Metabolisation products of dimethylarsinate did not occur under the present experimental conditions. The vitality of the angiosperms seems to be very dependent on the ability of the plant to reduce arsenate to arsenite.

Especiação analítica de compostos de arsênio empregando métodos voltamétricos e polarográficos: uma revisão comparativa de suas principais vantagens e aplicações

This paper provides a review on voltammetric and polarographic methods for the speciation analysis of inorganic and organic arsenic compounds in different matrices. A discussion on the main advantages of electroanalytical methods in comparison with other analytical methods employed for arsenic speciation is presented. The mechanistic aspects of the most relevant techniques employing cathodic and anodic stripping voltammetry as well as polarographic methods published in the last twenty five years are summarized and discussed. The bibliographic references cited in this work were selected from the Web of Science (published by the ISI) and the main journals of analytical chemistry.

Ranking of chemical substances based on the Japanese Pollutant Release and Transfer Register using partial order theory and random linear extensions

In 1997 a Pollutant Release and Transfer Register (PRTR) pilot project was initiated in Japan. In 1998 the project was expanded and in 1999 a law concerning the establishment of a national PRTR was adopted. Data on the emissions of chemical substances are therefore now being reported on a continuous base. In relation to the PRTR project data on toxicity have been collected. In order to make efficient use of the collected information on emission and toxicity it is useful to group or rank the chemical substances according to the impact on human health and the environment. It has recently been argued that partial order theory (POT) in combination with the use of linear extensions (LE) may be the most objective way to create a linear rank. The methodology has been further expanded to handle larger data sets by the use of random linear extensions (RLE). In this paper the Japanese PRTR data are ranked using the POT/RLE methodology. An average rank is established for chemical substances in the 1998 and 1999 PRTR in Japan. The top 10 chemical substances in the 1998 PRTR are: dichlorvos, inorganic arsenic compounds, cobalt compounds, beryllium compounds, fenitrothion, disulfoton, parathion, diazinon, 4,4 ′-diamino-3,3 ′-dichlorodiphenylmethane and antimony compounds. The top 10 chemical substances from the 1999 PRTR are PCBs, lead compounds, fenitrothion, dichlorvos, disulfoton, inorganic arsenic compounds, chlorothalonil, thiobencarb, chromium and HCFC-141b. The descriptor having the highest influence on the ranking of the 1998 PRTR data is the production volume, which, however, is not given in the 1999 PRTR. Further, the disagreement between the ranking with the lack of toxicity data substituted with mean and maximum values, respectively, strongly indicates a general need for further toxicological investigations.

Differential pulse cathodic stripping voltammetric speciation of trace level inorganic arsenic compounds in natural water samples

A simple, fast and sensitive speciation method is described for inorganic arsenic in water at the μg/l level, applicable in the laboratory and in the field, based on differential pulse cathodic stripping voltammetry (DPCSV). Only As(III) is deposited on a Hg electrode in the presence of Cu and Se in HCl medium. Determination of total As is performed by reducing As(V) to As(III) using sodium meta-bisulfite/sodium thiosulfate reagent stabilized with ascorbic acid. As(V) is quantified by difference. The detection limit (S/N>3) was 0.5 μg/l with a linear range from 4.5 to 180 μg/l. The relative standard deviation ( n=6) was 2.4, 2.5, 4.2% for As(III) and 8.0, 6.8, 9.0% for As(V) at levels of 45, 10, and 5 μg/l, respectively. Analysis of the NIST 1640 natural water standard yielded total arsenic concentration 26.5±3.4 μg/l ( n=3) compared to the certified value of 26.7 μg/l. Results obtained on several natural water samples analyzed both in the laboratory and on-site compared well with those obtained by HR ICP-MS, GFAAS and IC-AFS. Ions (phosphate, iron, manganese) commonly found in groundwater containing arsenic were found to have negligible interference.

In vitro DNA damage by arsenic compounds in a human lymphoblastoid cell line (TK6) assessed by the alkaline Comet assay.

Arsenic is classified as a carcinogen for humans, but as a possible genotoxic agent. Thus, taking into account the controversial data about how arsenic compounds are able to induce genetic damage, we investigated the possible genotoxic activity of different arsenic compounds in the TK6 human lymphoblastoid cell line using the alkaline Comet assay. Eight different inorganic and organic arsenical compounds have been selected as follows: three inorganic (sodium arsenite, sodium arsenate and sodium hexafluorarsenate) and five organic (monomethylarsonic and dimethylarsinic acids, arsenobetaine, tetramethylarsonium iodide and tetraphenylarsonium chloride). According to their toxicity and genotoxicity, the highest concentration tested was 10 mM, and the duration of the treatments was 30 min or 3 h. The results indicate that some compounds belonging to both the organic and inorganic species were able to induce significant increases in the tail moment, the parameter used to determine genotoxicity. Thus, the inorganic compounds sodium arsenite and sodium arsenate (but not sodium hexafluoroarsenate) were genotoxic, while among the organoarsenic species tested only tetramethylarsonium iodide and tetraphenylarsonium chloride compounds (but not monomethylarsonic, dimethylarsinic acids and arsenobetaine) induced significant increases in the tail moment. Nevertheless, genotoxic induction was generally only observed at the highest doses tested.

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

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.

Evaluation of in vivo acute immunotoxicity of a major organic arsenic compound arsenobetaine in seafood

In this study, we observed the in vivo acute immunotoxicity of a trimethyl arsenic compound, arsenobetaine (AsBe), which is present in large quantities in various marine animals that are daily ingested as seafood in many countries. The synthetic pure AsBe was orally administered to CDF 1 mice at a dose of 1.625 g/kg mouse weight once a day on days −6, −4, −2 and 0 (four times, total 6.5 g/kg mouse weight), and its effect on the immune organs and immune effector cells were assessed until day 8. Orally administered AsBe was temporally distributed to the immune organs, such as the spleen and thymus, but was not very toxic both quantitatively and qualitatively on these immune organs and immune effector cells, splenocytes, thymocytes, Peyer's patch lymphocytes and peritoneal macrophages. This finding suggests that the ingestion of AsBe contained in marine animals is relatively safe to the health of people who often consume marine animals in their daily diet.

Simultaneous determination of twelve inorganic and organic arsenic compounds by liquid chromatography–ultraviolet irradiation–hydride generation atomic fluorescence spectrometry

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.

Speciation of inorganic and methylated arsenic compounds by capillary zone electrophoresis with indirect UV detection: Application to the analysis of alkali extracts of As 2S 2 (realgar) and As 2S 3 (orpiment)

A capillary zone electrophoresis (CZE) method with indirect UV detection was developed to simultaneously separate inorganic and organic arsenic compounds including arsenite (iAs III), arsenate (iAs V), monomethylarsonate and dimethylarsenic acid (DMA V). 2,6-Pyridinedicarboxylic acid (PDC) and n-hexadecyltrimethylammonium hydroxide (CTAOH) were selected to compose a background electrolyte (BGE), where PDC was used as chromophore and CTAOH functioned as electroosmotic flow (EOF) modifier to reduce/eliminate EOF. The choice of detection wavelength, the optimization of BGE pH, and effects of applied electric field strength and temperature on separation were further investigated. The limits of detection for the targeted analytes were between 0.19 and 0.23 ppm as molecule. Good linearity of more than three orders of magnitude was obtained. Repeatability of migration times and peaks areas were 0.8–1.7 and 3.4–6.9% R.S.D.; whereas reproducibility were 1.2–2.2 and 3.6–7.1% R.S.D., respectively. The established CZE method was then applied to analyze the alkali extracts of realgar (As 2S 2) and orpiment (As 2S 3). The main components in both alkali extracts were identified to be iAs III and iAs V.

Identification of organic arsenic, tin, antimony and tellurium compounds in environmental samples by GC-MS

Abstract In this study, the potential of GC-MS for structure analysis of organometal(loid) species of arsenic, tin, antimony and tellurium in environmental samples was investigated. Analytes were ionic organometal(loid) species from compost samples, which were derivatised with NaBH 4 before introduction into the GC/MS via a purge and trap system, as well as volatile species from hydrothermal gases sampled on SPME-fibres. Several organic species of arsenic, tin, antimony and tellurium were identified. By scanning the chromatogram for typical fragments of organoarsenic compounds seven arsenic species were identified. To our knowledge three of them (diarsine, monomethyl diarsine and dimethylarsenomercaptane) have not been reported in environmental samples so far. To further exclude artefacts being misinterpreted as volatile organometal(loid)s, measurements of volatile arsenic species naturally occurring in hydrothermal samples with SPME-GC-MS were performed. The determination of dimethylarsenomercaptane in these samples confirms that this compound which was also found after derivatisation of ionic arsenic species is not an artefact. A strategy for the identification of unknown species whose structure cannot be elucidated by library comparison or with the help of isotopic patterns is presented. The necessity of positive identification of unknown species and confirmation of known and assumed compounds for speciation analysis is highlighted and the applicability of quadrupol GC/MS for this purpose is stated.