Organic Mercury Species Research Articles

Mercury speciation in environmental samples by cold vapour atomic absorption spectrometry with in situ preconcentration on a gold trap

A method has been developed for the determination of total and organic mercury in biological materials and sediments. A microwave assisted mineralization of the organic mercury, after its extraction from the matrix, is described. This procedure warrants complete transformation of Hg(II) and, consequently, the quantitative reduction to Hg(0). The conditions for mercury reduction were optimized by a central composite design. The preconcentration of the analyte has been achieved by amalgamation on a trap system, consisting in a pyrolytic graphite platform wound by a gold wire. Mercury was determined by cold vapour atomic absorption spectrometry. The method was validated by the analysis of two certified reference materials and applied to the determination of total and organic mercury species in mussel tissues and sediments. The method is simple and practical, and offers the advantage of not requiring special equipment to measure inorganic and organic mercury simultaneously.

Seasonal behavior of mercury species in waters and sediments from the Negro River Basin, Amazon, Brazil

Total (HgT), reactive (HgR) and organic (HgORG) mercury species have been quantified in non-filtered waters collected from the Negro River Basin, Amazon (from January/2002 through January/2004), in both black and white water bodies. Black waters presented the highest HgT, HgORG and HgR concentration (29.1 ng L-1, 1.63 ng L-1 and 3.9 ng L-1, respectively), while, white waters presented the lowest HgT, HgORG and HgR concentration (8.8 ng L-1, 0.49 ng L-1 and 1.2 ng L-1, respectively). An inverse correlation between HgT and the water level over the basin was obtained, although the HgORG concentration has increased in the first rainy months and then decreased as the water level rose. Total mercury in surface sediments (0-10 cm) ranged from 70 to 271 mg kg-1 being the methylmercury 0.47-1.79 % of this stock.The results indicate that HgR and the labile dissolved organic matter were introduced into the aquatic environment during the flooding season, especially in the earlier stages, thus contributing to mercury methylation.

Photo-induced chemical vapour generation with formic acid: novel interface for high performance liquid chromatography-atomic fluorescence spectrometry hyphenated system and application in speciation of mercury

Based on a novel photo-induced chemical vapour generation (CVG) with formic acid instead of the conventional K2S2O8/KBH4 system, an on-line coupled HPLC and atomic fluorescence spectrometry procedure was developed for the speciation of inorganic mercury, methylmercury (MeHg), ethylmercury (EtHg) and phenylmecury (PhHg). Under UV irradiation, the decomposition of organic mercury species and the reduction of Hg2+ could be completed in one step with this proposed photo-induced CVG system. The novel CVG system used formic acid only, which simplified the flow system and avoided the possibility of contamination originating from additional chemicals. A number of operating parameters including organic acid species, concentration of formic acid, pH, flow rate of formic acid and flow rate of carrier gas were optimized, and comparable method sensitivities with the conventional K2S2O8/KBH4 system were obtained. The limits of detection at the optimized conditions were 0.81, 0.20 and 0.87 μg L−1 for MeHg, EtHg and PhHg, respectively. The developed method was validated by determination of certified reference material DORM-2 and was further applied in determination of seafood samples. The new CVG system is simple, environmentally benign, and inexpensive for the speciation analysis of mercury. It is expected to have similar applications in other analytical atomic spectrometric techniques as well as speciation of other organic metal compounds.

Dose and Hg species determine the T-helper cell activation in murine autoimmunity

Inorganic mercury (mercuric chloride—HgCl2) induces in mice an autoimmune syndrome (HgIA) with T cell-dependent polyclonal B cell activation and hypergammaglobulinemia, dose- and H-2-dependent production of autoantibodies targeting the 34kDa nucleolar protein fibrillarin (AFA), and systemic immune-complex deposits. The organic mercury species methylmercury (MeHg) and ethylmercury (EtHg—in the form of thimerosal) induce AFA, while the other manifestations of HgIA seen after treatment with HgCl2 are present to varying extent. Since these organic Hg species are converted to the autoimmunogen Hg2+ in the body, their primary autoimmunogen potential is uncertain and the subject of this study.A moderate dose of HgCl2 (8mg/L drinking water−internal dose 148μgHg/kg body weight [bw]/day) caused the fastest AFA response, while the induction was delayed after higher (25mg/L) and lower (1.5 and 3mg/L) doses. The lowest dose of HgCl2 inducing AFA was 1.5mg/L drinking water which corresponded to a renal Hg2+ concentration of 0.53μg/g. Using a dose of 8mg HgCl2/L this threshold concentration was reached within 24h, and a consistent AFA response developed after 8–10 days. The time lag for the immunological part of the reaction leading to a consistent AFA response was therefore 7–9 days. A dose of thimerosal close to the threshold dose for induction of AFA (2mg/L drinking water—internal dose 118μgHg/kgbw per day), caused a renal Hg2+ concentration of 1.8μg/g. The autoimmunogen effect of EtHg might therefore be entirely due to Hg2+ formed from EtHg in the body. The effect of organic and inorganic Hg species on T-helper type 1 and type 2 cells during induction of AFA was assessed as the presence and titre of AFA of the IgG1 and IgG2a isotype, respectively. EtHg induced a persistent Th1-skewed response irrespectively of the dose and time used. A low daily dose of HgCl2 (1.5–3mg/L) caused a Th1-skewed AFA response, while a moderate dose (8mg/L) after 2 weeks resulted in a balanced or even Th2-skewed response. Higher daily doses of HgCl2 (25mg/L) caused a balanced Th2–Th1 response already from onset. In conclusion, while metabolically formed Hg2+ might be the main AFA-inducing factor also after treatment with EtHg, the quality of the Hg-induced AFA response is modified by the species of Hg as well as the dose.

Expression of organomercurial lyase in eastern cottonwood enhances organomercury resistance

Release of inorganic mercury pollutants into shallow aquatic environments has resulted in the bacterial production of a more toxic organic mercury species, methylmercury. The bacterial organomercurial lyase (MerB) catalyses the protonolysis of the carbon-mercury bond and releases Hg(II), a less toxic, non-biomagnified form of mercury. Our objective was to engineer eastern cottonwood (Populus deltoides), a fast-growing tree adapted to growth in riparian environments, with the merB gene to explore its potential for phytoremediation of mercury. We produced multiple eastern cottonwood clones expressing a modified bacterial merB gene, confirmed that the gene was expressed in the transclones and tested the regenerated plants for their ability to tolerate exposure to an organic mercury source, phenylmercuric acetate (PMA), in vitro and in hydroponic culture, compared to wild-type control trees. Transgenic merB plants expressed high levels of MerB protein and showed some evidence of higher resistance to the organic mercury than wild-type plants, producing longer roots under exposure to PMA in vitro, although hydroponic culture results were inconclusive. Our results indicate that in order for merB to be useful in eastern cottonwood trees designed to degrade methylmercury at mercury-contaminated aquatic sites, it will probably need to be combined with other genes such as merA.

Methylmercury induces activation of Notch signaling

Methylmercury (MeHg) toxicity in humans manifests deficits in neurological function. Cases of prenatal exposure to mercury have established that the developing nervous system is most highly susceptible to perturbation by MeHg. At a cellular level, MeHg-induced defects result from altered neuronal proliferation, migration and pathfinding. However, the molecular targets of MeHg that give rise to these outcomes are not fully understood. In an overall effort to identify the fundamental molecular targets of MeHg in neural development, we have explored the effects of MeHg on cell surface receptor function using the simplified Drosophila model. In this study, we investigated the potential role of MeHg to alter activity of the Notch receptor pathway, a highly conserved cell–cell signaling mechanism that controls cell fate decisions, proliferation, migration and neurite outgrowth in neural development. Notch receptor activation requires proteolysis by a cell surface ADAM metalloprotease. ADAM proteases are required for normal neural development and are activated by organomercurials, thus presenting a possible mechanism for MeHg neurotoxicity. Here, we demonstrate a concentration- and time-dependent increase in Notch receptor activity with MeHg exposure in three distinct Drosophila cell lines. Ten micromolar MeHg results in a 4–5.5-fold increase in Notch signaling as measured by the upregulation of two enhancer of split (E(spl)) target genes. MeHg-induced Notch activity also correlates with receptor proteolysis. Targeted knockdown of Notch protein expression demonstrates that MeHg induced E(spl) activation specifically requires the Notch receptor. Furthermore, MeHg-induced Notch activity is partially attenuated by the metalloprotease inhibitor, GM6001, consistent with a model in which MeHg promotes activation of ADAM metalloproteases. Finally, we demonstrate that inorganic HgCl 2 is significantly less active in inducing Notch activity, suggesting a mechanism specific to organic species of mercury. Overall, these data identify Notch as a potential target for MeHg toxicity in the developing nervous system.

Alteration of the spontaneous systemic autoimmune disease in (NZB × NZW)F1 mice by treatment with thimerosal (ethyl mercury)

Inorganic mercury may aggravate murine systemic autoimmune diseases which are either spontaneous (genetically determined) or induced by non-genetic mechanisms. Organic mercury species, the dominating form of mercury exposure in the human population, have not been examined in this respect. Therefore, ethyl mercury in the form of thimerosal, a preservative recently debated as a possible health hazard when present in vaccines, was administered in a dose of 0.156-5 mg/L drinking water to female (NZB x NZW)F1 (ZBWF1) mice. These mice develop an age-dependent spontaneous systemic autoimmune disease with high mortality primarily due to immune-complex (IC) glomerulonephritis. Five mg thimerosal/L drinking water (295 microg Hg/kg body weight (bw)/day) for 7 weeks induced glomerular, mesangial and systemic vessel wall IC deposits and antinuclear antibodies (ANA) which were not present in the untreated controls. After 22-25 weeks, the higher doses of thimerosal had shifted the localization of the spontaneously developing renal glomerular IC deposits from the capillary wall position seen in controls to the mesangium. The altered localization was associated with less severe histological kidney damage, less proteinuria, and reduced mortality. The effect was dose-dependent, lower doses having no effect compared with the untreated controls. A different effect of thimerosal treatment was induction of renal and splenic vessel walls IC deposits. Renal vessel wall deposits occurred at a dose of 0.313-5 mg thimerosal/L (18-295 microg Hg/kg bw/day), while splenic vessel wall deposits developed also in mice given the lowest dose of thimerosal, 0.156 mg/L (9 microg Hg/kg bw/day). The latter dose is 3- and 15-fold lower than the dose of Hg required to induce vessel wall IC deposits in genetically susceptible H-2s mice by HgCl2 and thimerosal, respectively. Further studies on the exact conditions needed for induction of systemic IC deposits by low-dose organic mercurials in autoimmune-prone individuals, as well as the potential effect of these deposits on the vessel walls, are warranted.

Mercury speciation by liquid chromatography coupled with on-line chemical vapour generation and atomic fluorescence spectrometric detection (LC–CVGAFS)

Reverse phase chromatography (RPC) coupled on-line with UV–vis diode array detector (DAD) and cold vapour generation atomic fluorescence spectrometry (CVGAFS) is proposed for the speciation and determination of inorganic and organic mercury (methylmercury, ethylmercury and phenylmercury) in the form of cysteine, penicillamine and glutathione complexes. The mercury–thiol complexes are separated on a C 18 Reverse Phase column and oxidized on-line with bromine, generated in situ by KBr/KBrO 3 in HCl medium, in order to fast convert organic mercury species to inorganic mercury in less than 2.5 s, at room temperature, in a 30 cm knitted coil. Hg(II) is selectively detected by AFS in a Ar/H 2 miniaturized flame after sodium borohydride reduction to Hg 0. Under optimized conditions, on-line bromine treatment gives recoveries of thiol-complexed methylmercury, ethylmercury and phenylmercury with respect to inorganic mercury ranging between 79 and 85%, 80 and 85%, 63 and 76%, respectively, depending on the complexing thiol employed. Optimized elution conditions were provided in the three complexing agents. The detection limits (LODc) for inorganic mercury, methylmercury, ethylmercury and phenylmercury, in the optimized conditions complexed with thiols were about 16, 18, 18 and 20 pg (as mercury), respectively, a relative standard deviation (R.S.D) ranging between 1.5 and 2.0%, and a linear dynamic range between 0.1 and 100 ng injected. LC–DAD–CVGAFS method has been validated by analysing two certificate reference material, DORM-2 and NIES CRM 13, obtaining 98 ± 6 and 97 ± 5% of methylmercury recovered, respectively.

Sensitive Method for Trace Determination of Mercury in Wines Using Electrothermal Atomic Absorption Spectrometry

An accurate, simple and precise method for total mercury determination in wines is described. Liquid/liquid extraction of inorganic and organic mercury species directly from untreated wine samples is recommended as a preconcentration procedure prior to determination by electrothermal atomic absorption spectrometry (ETAAS). Ammonium pyrrolidinedithiocarbamate was used as complexation agent. The optimal instrumental parameters for ETAAS measurement of mercury species extracted are proposed. The detection limit for total mercury determination is 0.2 µg L−1. The relative standard deviation is 15–22% for mercury in wine in the range of 0.2–5 µg L−1. The proposed procedure has been successfully applied to the determination of mercury in bottled wines in Bulgaria and Macedonia.

Supercritical fluid extraction of mercury species

Supercritical fluid extraction was used to recover organic and inorganic mercury species. Variations in pressure, water, methanol, and chelator create methods that allowed separation of inorganic from organic mercury species. When extracted using a compromised set of extraction conditions, the order of extraction was methyl, phenyl and inorganic mercury. For the individually optimized conditions, quantitative recoveries were observed. Level as low as 20 ppb were extracted and then determined using ICP.

PROLONGATION OF HUMAN NEUTROPHIL SURVIVAL BY LOW-LEVEL MERCURY VIA INHIBITION OF SPONTANEOUS APOPTOSIS

Low levels of organic and inorganic mercury compounds have been reported previously to induce cell death by apoptosis in human peripheral blood mononuclear cells (MNC), but little is known about their potential effects on the viability and death of polymorphonuclear neutrophils (PMN). In contrast to MNC, PMN are known to undergo readily spontaneous apoptosis both in vivo and in vitro. Therefore, it was hypothesized that PMN may differ from MNC in their reactions to low mercury levels. The effects of methylmercuric chloride (MeHgCl) and mercuric chloride (HgCl 2 ) were evaluated in concentration- response and time-course studies on human PMN viability and on their modes of cell death after in vitro incubation at 37°C. Cell death by apoptosis or necrosis was assessed by annexin V-fluorescein isothiocyanate binding to externalized phosphatidylserine in conjunction with propidium iodide, and flow cytometry analysis. Morphologic counting of pyknotic nuclei and the fluorescence properties of the DNA-binding dye Hoechst 33342 in combination with propidium iodide were used to further confirm apoptotic cell death and to characterize the sequence of Hg-induced cell death. Results show that low concentrations of MeHgCl (1-7.5 µ M ) that were cytotoxic to MNC actually inhibited PMN spontaneous apoptosis. Low-level HgCl 2 reproduced the anti-apoptotic effects of MeHgCl on PMN, but to a lower extent. Higher concentrations of MeHgCl and HgCl 2 were necro-genic to PMN, but MeHgCl was about an order of magnitude more toxic, and discrete differences were observed in the modalities of cell death induced by both species. These data reveal for the first time that (1) low levels of organic and inorganic mercury species protect human PMN from cell death via inhibition of spontaneous apoptosis, and (2) PMN are more resistant than MNC to mercury-induced cytotoxicity. Since delayed apoptosis and increased resistance to toxicant-induced cell death may lead to excessive accumulation of senescent PMN, evidence indicates that findings of this study may have implications for mercury-induced autoimmunity and inflammation.

Effects of 2,3-dimercapto-1-propanesulfonic acid (DMPS) on tissue and urine mercury levels following prolonged methylmercury exposure in rats.

Methylmercury, a potent neurotoxicant, accumulates in the brain as well as the kidney during chronic exposure. We evaluated the capacity of 2,3-dimercapto-1-propanesulfonic acid (DMPS), a tissue-permeable metal chelator, to reduce brain, kidney, and blood Hg levels and to promote Hg elimination in urine following exposure of F-344 rats to methylmercury hydroxide (MMH) (10 ppm) in drinking water for up to 9 weeks. Inorganic (Hg2+) and organic (CH3Hg+) mercury species in urine and tissues were assayed by cold vapor atomic fluorescence spectroscopy (CVAFS). Following MMH treatment for 9 weeks, Hg2+ and CH3Hg+ concentrations were 0.28 and 4.80 microg/g in the brain and 51.5 and 42.2 microg/g in the kidney, respectively. Twenty-four hours after ip administration of a single DMPS injection (100 mg/kg), kidney Hg2+ and CH3Hg+ declined 38% and 59%, whereas brain mercury levels were slightly increased, attributable entirely to the CH3Hg+ fraction. Concomitantly, Hg2+ and CH3Hg+ in urine increased by 7.2- and 28.3-fold, respectively, compared with prechelation values. A higher dose of DMPS (200 mg/kg) was no more effective than 100 mg/kg in promoting mercury excretion. In contrast, consecutive DMPS injections (100 mg/kg) given at 72-h intervals significantly decreased total mercury concentrations in kidney, brain, and blood. However, the decrease in brain and blood mercury content was restricted entirely to the CH3Hg+ fraction, consistent with the slow dealkylation rate of MMH in these tissues. Mass balance calculations showed that the total amount of mercury excreted in the urine following successive DMPS injections corresponds quantitatively to the total amount of mercury removed from the kidney, brain, and blood of MMH-exposed rats. These findings confirm the efficacy of consecutive DMPS treatments in decreasing mercury concentrations in target tissue and in reducing overall mercury body burden. They demonstrate further that the capacity of DMPS to deplete tissue Hg2+ is highly tissue-specific and reflects the relative capacity of the tissue for methylmercury dealkylation. In light of this observation, the inability of DMPS to reduce Hg2+ levels in brain or blood may explain the inefficacy of DMPS and similar chelating agents in the remediation of neurotoxicity associated with prolonged MMH exposure.

Mercury speciation using the capillary cold trap coupled with microwave-induced plasma atomic emission spectroscopy

In this paper the capillary cold trap (CCT) is presented as a novel sample introduction and separation system for microwave-induced plasma detection. The method is based on cryogenic trapping and gas chromatographic separation carried out within the same capillary. The device, which comprises a derivatization step, on-line gas phase extraction, preconcentration and analyte separation, is semi-automated and all operational parameters are adjustable via an in-house developed control unit, regulating the selected parameters throughout the analysis process. Detection was carried out using a 2.45 GHz microwave-induced argon discharge sustained in a TM010 Beenakker cavity and emission lines were recorded by means of a ST6-UV CCD camera provided by the Santa Barbara Instrument Group. The detection limits achieved were 6.0, 0.95 and 1.25 ng L−1 for dimethylmercury, methylmercury and inorganic mercury, respectively. A complete chromatogram could be obtained within 3 min, resulting in the duration of one whole analysis cycle of about 15 min. The proposed method was validated by the analysis of a reference material (BCR 710) and applied to mercury speciation in different sample matrices such as oyster, tuna fish and sediments after microwave-assisted extraction. The total mercury concentration in real samples was in the range of 0.2–11 mg kg−1, of which up to 75% corresponded to organic mercury species.

Determination of Mercury by Cold-Vapor Atomic Absorption Spectrometry with Preconcentration on a Gold-Trap

The determination of trace levels of mercury by flow injection cold-vapor atomic absorption spectrometry with gold amalgamation was evaluated for organic and inorganic mercury species. The effect of the sodium tetrahydroborate(III) and hydrochloric acid concentrations as well as various instrumental parameters on the analytical performance was studied. The influence of the blank as well as the laboratory procedure for reagent purification was evaluated. The procedure was applied to the determination of mercury in lake water, while focusing on the importance of the sampling protocols.

Sources of systematic errors in mercury speciation using Grignard reagents and capillary gas chromatography coupled to atomic spectrometry

This paper describes spectral and chemical interferences that occurred when using Grignard reagents for derivatisation of mercury species and microwave-induced plasma atomic emission (MIP-AES) or atomic absorption spectrometry for detection. When butylmagnesium chloride, dissolved in THF, was used to convert methyl and inorganic mercury to non-polar butyl derivatives it was established that reaction by-products, eluted near to the methylbutylmercury peak, caused changes in the background emission or absorption. The use of other Grignard reagents, pentyhnagnesium bromide and hexylmagnesium bromide, was investigated. These showed poor derivatisation efficiency and species stability. Iodide and bromide at concentrations of the order of 1 mg 1 −1 were found to de-alkylate organic mercury species when present in an organic matrix. In addition, if these halides were not completely removed from the GC column under a normal chromatographic run, they reacted with derivatised mercury species in subsequently injected samples. Organomercury iodide or bromide compounds were formed and these were identified by GC-MS. This reaction reduced the signal magnitude for dibutylmercury, corresponding to inorganic mercury. Replacement of indigenous methyl groups with butyl groups was demonstrated on prolonged contact of samples containing methyl and dimethylmercury with butylmagnesium chloride. The degree of methyl group replacement appeared to be proportional to the reaction time.

Interactions between dissolved organic carbon and mercury species in surface waters of the Florida Everglades

An ultrafiltration procedure has been developed to study the interaction between organic C and Hg species in natural waters, and a pilot study was conducted in the surface waters of the Florida Everglades. Compared to total Hg, CH 3Hg shows different distribution patterns in the suspended particulate, colloidal, and truly dissolved phases. Colloidal forms (0.22 μm, 3 kDa) contain the majority of the total dissolved Hg, while the amount found in the truly dissolved fraction (<3 kDa) is small (about 10%). However, CH 3Hg, which shows strong binding capability with low molecular-weight dissolved organic C, is present almost entirely in the lower molecular-weight fraction of the colloids and in the truly dissolved fraction. Quantitative CH 3Hg data correlate well with those for dissolved organic C, an indication that the organic matter present in the system plays an important role in the fate and transport of organomercury. Distribution coefficients between water and the different-sized fractions of the dissolved organic C were determined for both total Hg and CH 3Hg. Results for total Hg were in general agreement with other reports resulting from studies of molecular size distributions of total Hg in freshwater systems. This is, to the best of our knowledge, the first report of such distribution profiles for CH 3Hg between different-sized fractions of dissolved organic C in natural waters.

Reprocessing and Reuse of Waste Tire Rubber to Solve Air-Quality Related Problems

There is a potential for using waste tire rubber to make activated-carbon adsorbents for air-quality control applications. Such an approach provides a recycling path for waste tires and the production of new adsorbents from a low-cost waste material. Tire-derived activated carbons (TDACs) were prepared from waste tires. The resulting products are generally mesoporous, with N2−BET specific surface areas ranging from 239 to 1031 m2/g. TDACs were tested for their ability to store natural gas and remove organic compounds and mercury species from gas streams. TDACs are able to achieve 36% of the recommended adsorbed natural gas (methane) storage capacity for natural-gas-fueled vehicles. Equilibrium adsorption capacities for CH4 achieved by TDACs are comparable to Calgon BPL, a commercially available activated-carbon adsorbent. The acetone adsorption capacity for a TDAC is 67% of the adsorption capacity achieved by BPL at 1 vol % acetone. Adsorption capacities of mercury in simulated flue-gas streams are, in ge...

Reversed-phase high-performance liquid chromatography of pyrrolidinedithiocarbamate complexes of mercuric species using amperometric and coulometric detection

A reversed-phase high-performance liquid chromatographic method has been developed for the determination of organic and inorganic mercury species as pyrrolidinedithiocarbamic complexes using electrochemical detection. These complexes were prepared off-line and separated using as mobile phase a mixture of methanol-water (75:25) containing KNO 3 as supporting electrolyte. The organomercury complexes were detected in both amperometric and coulometric mode, at + 1.15 V and + 0.90 V respectively. The detection limits ranged from 0.16 ng to 2.8 ng.

Methylmercury in hair of fishermen from Turkish coasts.

Environmental methylmercury mainly arises from the methylation of inorganic mercury. The change in speciation of mercury from inorganic to methylated forms is the first step in the aquatic bioaccumulation processes. The bioconcentration factor of methylmercury in fish tissue to that in water is usually between 10{sup 4} and 10{sup 5}. Among seafood, fish products are the main source of methylmercury absorbed by men from the environment. Since Minimata epidemic health injuries and deaths in relation to mercury pollution, environmental and biological monitoring of inorganic and organic mercury species has gained importance through out the world and many reports have been published on the health effects and biological monitoring of mercury compounds including some Mediterranean countries. This study focuses on methylmercury in hair of fisherman living in different geographical Turkish coasts and relationship to eating fish habit. 17 refs., 1 fig., 2 tabs.

Sampling and analysis of mercury species in effluent gases derived from waste incineration

Mercury and its compounds are highly toxic. Therefore, the determination of mercury species present in flue gases from combustion sources is extremely important. Mercury is initially emitted from the combustion chamber as mercury vapour. However, as the combustion products cool the mercury vapour can react with a variety of other flue gas components to form a range of inorganic and possibly organic mercury species. The diversity of mercury compounds which could form means that a sampling and analysis procedure is needed which can determine the elemental, inorganic and organic mercury content of the flue gases. This would allow appropriate clean-up procedures to be employed and, if necessary, the modification of the process to eliminate the formation of particularly toxic mercury species. In this work a sampling train has been developed using model mercury compounds to efficiently trap elemental, inorganic and organic mercury from a hot gaseous environment. Chemical analysis of the sampling mediums was carried out by HPLC-UV to speciate between inorganic and organic mercury.