Methylmercury Species Research Articles

Chemical speciation of methylmercury and mercury(II) cations in fish by new fluorogenic naphthalimide alkynyl gold complexes: The ultimate test for detecting fish contamination

The proof of concept of a new portable protocol for the detection and speciation of methylmercury and mercury(II) cations in fish samples is described. In this way, traces of methylmercury and/or mercury(II) cations in fish were quantitatively detected using an elaborated protocol and including a fluorescent sensor. In-the-field accurate results were obtained due to the selective behavior of the chemical sensor in the presence of both cations, working at very low concentrations of mercury species in fish under standard laboratory conditions, that are suitable for daily use in ordinary sampling by border companies importing fish or remote laboratories where large devices cannot be carried. The reported fish protocol is useful under real-life conditions for analyzing fish for the presence of methylmercury in contrast to total mercury analysis. The combination of the protocol and the fluorescent reporter constitutes the ultimate test for fish contamination by mercury(II) species in the workplace. The reported limits of detection of 0.72 nM for Hg2+ and 1.62 nM for CH3Hg+ and the closely related values of the two mercury(II) species in fish samples, obtained by ICP-MS analysis and fluorescent measurements, make the method suitable for daily control of methylmercury in fish under the EU legislation parameters and the WHO recommendations.

Mercury cycling in contaminated coastal environments: modeling the benthic-pelagic coupling and microbial resistance in the Venice Lagoon

Anthropogenic activities have been releasing mercury for centuries, and despite global efforts to control emissions, concentrations in environmental media remain high. Coastal sediments can be a long-term repository for mercury, but also a secondary source, and competing processes in marine ecosystems can lead to the conversion of mercury into the toxic and bioaccumulative species methylmercury, which threatens ecosystem and human health. We investigate the fate and transport of three mercury species in a coastal lagoon affected by historical pollution using a novel high-resolution finite element model that integrates mercury biogeochemistry, sediment dynamics and hydrodynamics. The model resolves mercury dynamics in the seawater and the seabed taking into account partitioning, transport driven by water and sediment, and photochemical and microbial transformations. We simulated three years (early 2000s, 2019, and 2020) to assess the spatio-temporal distribution of mercury species concentrations and performed a sensitivity analysis to account for uncertainties. The modeled mercury species concentrations show high temporal and spatial variability, with water concentrations in some areas of the lagoon exceeding those of the open Mediterranean Sea by two orders of magnitude, consistent with available observations from the early 2000s. The results support conclusions about the importance of different processes in shaping the environmental gradients of mercury species. Due to the past accumulation of mercury in the lagoon sediments, inorganic mercury in the water is closely related to the resuspension of contaminated sediments, which is significantly reduced by the presence of benthic vegetation. The gradients of methylmercury depend on the combination of several factors, of which sediment resuspension and mercury methylation are the most relevant. The results add insights into mercury dynamics at coastal sites characterized by a combination of past pollution (i.e. sediment enrichment) and erosive processes, and suggest possible nature-based mitigation strategies such as the preservation of the integrity of benthic vegetation and morphology.

Assessing comparability and uncertainty of analytical methods for methylated mercury species in seawater

BackgroundThe relative distribution and importance of monomethylmercury (MMHg) and dimethylmercury (DMHg) in seawater is still under debate. A lack of comparability between measurements at sub-picomolar levels hampered the further understanding of the biogeochemical Hg cycle. To overcome this, we assessed the relative standard measurement uncertainties (Uex,r) for direct measurements of MMHg and DMHg by species-specific isotope dilution ICP-MS and cryo-focusing GC-ICP-MS at femtomolar concentrations. Furthermore, Uex,r was determined for the indirect determination of DMHg (DMHgcalc = MeHg - MMHg) and MeHg (MeHgcalc = MMHg + DMHg) to compare the two methodologies. ResultsExpanded Uex,r (confidence interval of 95%) for cryo-focusing GC-ICP-MS was 14.4 (<50 fM) and 14.2% (>50 fM) and for SS-ID GC-ICP-MS 5.6 (<50 fM) and 3.7% (>50 fM). For concentrations above 50 fM, Uex,r for DMHgcalc was always lower than for direct measurements (14.2%). For MeHgcalc, on the other hand, Uex,r was always higher for concentrations above 115 fM (range: 3.7–13.9%) than for direct measurements (3.7%). We evaluated the comparability of directly measured and calculated DMHg and MeHg concentrations based on Hg speciation measurements for two vertical profiles in the Mediterranean Sea. We show that directly measured and indirectly determined DMHg and MeHg concentrations yield comparable results. SignificanceOur results validate the application of the indirect method for the determination of DMHg if a direct measurement method with a low Uex,r such as isotope dilution is used for MMHg and MeHg measurements. The validation of the indirect measurement approach opens new possibilities to generate more precise and accurate DMHg data in the global ocean.

Analytical Methods, Occurrence, Fate, and Toxicity of Ethylmercury in the Environment: Review and Outlook

Studies on the environmental fate and risk of mercury (Hg) have been mostly focused on total mercury and a very toxic species methylmercury (MeHg). However, another organic Hg species, ethylmercury (EtHg), has long been neglected, partly due to the analytical limitations. The generally used aqueous ethylation for analyzing MeHg converts both Hg2+ and EtHg into diethylmercury, making it impossible to distinguish EtHg from Hg2+. Thanks to the emerging methods other than ethylation derivatization, EtHg has been identified in soils and sediments from a variety of sites, with a similar concentration to MeHg in some cases (e.g., the Florida Everglades). More importantly, results from recent studies also suggested that EtHg in the environment is derived not only from anthropogenic input (as bactericide, etc.), but also possibly from unknown natural formation pathways. Unfortunately, the environmental aspects, including formation, transport, transformation, bioaccumulation, and toxicity of EtHg, are still not well understood, limiting our understanding of this “new” organic Hg species. In this review, the current analytical methods focusing on gas/liquid chromatography coupled with atomic spectrometer for EtHg are summarized. Then, the occurrence of EtHg and its possible natural sources in the environment are discussed. Finally, the environmental transport, degradation, bioaccumulation, and toxicity of EtHg are discussed. It is expected that this review would provide comprehensive background and important clues to understand the natural occurrence and fate of EtHg.

Determination and speciation of methyl mercury and total mercury in fish tissue samples by gold-coated W-coil atom trap cold vapor atomic absorption spectrometry

A sensitive analytical technique was developed where gaseous mercury formed by sodium tetrahydroborate reduction is transported to and trapped on a resistively heated gold-coated Tungsten-coil atom trap for in situ preconcentration. This technique was applied successfully for determination and speciation of methyl mercury and total mercury in some fish tissue samples (liver, muscle and gill) obtained from Muğla province. The analytical parameters were optimized both for trap and no-trap studies. Under the optimized conditions, a limit of detection (LOD) of 6.0 ng/L was obtained. The precision was evaluated by relative standard deviation (RSD%) corresponding to 4.1% (n = 11). Accuracy of the proposed method was evaluated by analyzing “DOLT:5 Dogfish Liver”, “NIST SRM 1640a Trace elements in natural water” and “NIST 1946 Lake Superior fish tissues”. The measurements of the certified reference materials were in good agreement with the certified values at the 95% confidence level.

Distribution of total mercury and methylated mercury species in Central Arctic Ocean water and ice

The central Arctic Ocean remains largely unexplored when it comes to the presence and cycling of mercury and its methylated forms including mono- and dimethylmercury (MMeHg and DMeHg, respectively). In this study, we quantified total Hg (HgT) and methylated Hg species in seawater, ice cores, snow, brine, and water from melt ponds collected during the SWEDARCTIC 2016 expedition to the Amerasian and Eurasian side of the Lomonosov Ridge. In the water column, concentrations of HgT, MMeHg and DMeHg ranged from 0.089 to 1.5 pM, <25 to 520 fM and from <1.6 to 160 fM, respectively. HgT was enriched in surface waters while MMeHg and DMeHg were low at the surface (i.e. in the polar mixed layer) and enriched at a water depth of around 200–400 m. A 1:2 ratio of DMeHg to MMeHg was observed in the water column suggesting a lower ratio in the central parts of the Arctic Ocean than what has previously been reported from other parts of the Arctic Ocean. At the ice stations, average HgT ranged from 0.97 ± 1.2 pM in the ice cores to 27 ± 17 pM in melt pond waters and average MeHgT (total MeHg) from 28 ± 15 fM in brine to 130 ± 18 fM in melt pond water. The HgT observed in melt ponds and brine was an order of magnitude greater than HgT observed in surface waters and HgT in the upper part of the ice-cores was ~4–8 times higher HgT in comparison to lower layers. Our study suggests that ice may act as a source of HgT to surface waters but not to be a likely source of the methylated Hg forms. Unlike elemental Hg, DMeHg did not enrich in surface waters covered by ice. Concentrations of DMeHg observed in the ice cores and other samples collected from the ice stations were low, suggesting ice to not act as a source of DMeHg to the atmosphere nor to surface waters.

Recent Trends and Future Perspectives of Emergent Analytical Techniques for Mercury Sensing in Aquatic Environments.

Environmental emissions of mercury from industrial waste and natural sources, even in trace amounts, are toxic to organisms and ecosystems. However, industrial-scale mercury detection is limited by the high cost, low sensitivity/specificity, and poor selectivity of the available analytical tools. This review summarizes the key sensors for mercury detection in aqueous environments: colorimetric-, electrochemical-, fluorescence-, and surface-enhanced Raman spectroscopy-based sensors reported between 2014-2021. It then compares the performances of these sensors in the determination of inorganic mercury (Hg2+ ) and methyl mercury (CH3 Hg+ ) species in aqueous samples. Mercury sensors for aquatic applications still face serious challenges in terms of difficult deployment in remote areas and low robustness, reliability, and selectivity in harsh environments. We provide future perspectives on the selective detection of organomercury species, which are especially toxic and reactive in aquatic environments. This review is intended as a valuable resource for scientists in the field of mercury sensing.

The metal-organic framework supported gold nanoparticles as a highly sensitive platform for electrochemical detection of methyl mercury species in the aqueous environment

Mercury readily methylates to form extremely toxic methylmercury (CH3Hg+) that seriously imparts central nervous systems' functionality in humans and animals. Therefore, the development of rapid CH3Hg+ determination methods for the detection of environmentally relevant concentrations is a research priority. We developed an electrochemical technique to detect CH3Hg+ with minimal sample preparations, cost-effectively. Gold nanoparticles (AuNPs) were synthesized on metal-organic frameworks (MOFs) in a facile way using potassium borohydride as a reductant. An electrochemical sensor was developed using Au nanoparticles and zeolitic imidazolate framework-67 (Au/ZIF67) modified glassy carbon electrode (Au/ZIF67 GCE) for the determination of CH3Hg+. The linear stripping current responses were ranging from 1 µg/L to 25 µg/L [CH3Hg+], with 0.571 µA/µgL-1 sensitivity and 0.05 µg/L detection limit. The outstanding performance of Au/ZIF67 modified GCE for CH3Hg+ detection might be attributed to the unique hollow structure and active Co sites of the ZIF67 skeleton and catalytic activity of AuNPs. The new electrochemical sensor shows good stability and no interference by metal ions in the matrix. The Au/ZIF67 modified GCE sensor shows a good promise in detecting CH3Hg+ in natural water.

Ultratrace mercury speciation analysis in rice by in-line solid phase extraction – liquid chromatography – atomic fluorescence spectrometry

For the first time, Hg2+ and methylmercury speciation analysis was accomplished by in-line SPE-LC-AFS. After modification with 0.1 mL of 0.001% (m:v) sodium diethyldithiocarbamate, a C18 microcolumn retained Hg2+ and MetHg in rice extract within 3 min; the captured Hg species were separated within 12 min in 0.25% (v:v) 2-mercaptoethanol + 60 mmol L-1 (m:v) ammonium acetate + 4% (v:v) acetonitrile. Under optimized conditions, the detection limits were 0.3 ng L−1 for Hg2+ and 0.2 ng L−1 for MetHg, respectively, with 10 mL injection vs. 0.1 mL eluent; in-line SPE achieved ∼ 100x enrichment. Method precision and accuracy were satisfactory at < 2% relative standard deviations (RSDs) for 20 ng L−1 of Hg2+ and MetHg and 95-102% recoveries for real rice samples. In-line SPE obviated human involvement and avoided invalid transportation between interfaces, rendering this SPE-LC-AFS method easy, compact, robust, yet sensitive in mercury speciation analysis to uphold food safety.

Rapid determination of femtomolar methylmercury in seawater using automated GC-AFS method: Optimisation of the extraction step and method validation

Among ionic mercury species methyl mercury (MMHg) is the most toxic form present in the environment, which is known to be bio-accumulative neurotoxin in the aquatic food chain and could provide the major route of exposure for humans to mercury through consumption of marine food products. The availability of reliable analytical methods for evaluating spatial and temporal contamination trends of MMHg in the ocean is an important prerequisite for marine monitoring. Sound strategies for marine monitoring call also for measurement systems capable of producing comparable analytical results with demonstrated quality.A sensitive analytical procedure for environmental monitoring of MMHg content in seawater, based on specific extraction and Gas Chromatography Atomic Fluorescence Spectrometry validated according to the requirements of international guidelines and standards, ISO 17025 and Eurachem guidelines, is presented in this study.The entire measurement process was described by mathematical equations and all factors influencing the results were systematically investigated. Selectivity, working range, linearity, recovery (94 ± 4%), repeatability (3.3%–4.5%), intermediate precision (2.9%), limits of detection (0.0004 ng kg−1as Hg) were systematically assessed. The relative expanded uncertainties obtained were in the range from 16% to 25%, (k = 2).Modelling of the entire measurement process related obtained values for MMHg in seawater to the International System of units (Kg). The potential of this analytical procedure was tested and additionally validated via inter laboratory comparison exercise organised under the Geotraces programme. Obtained results were in excellent agreement with the assigned values.The proposed analytical procedure from the sample preparation to the measurement step combined with the high efficiency of the new generation of the automated MMHg analyzers is fit for purpose for routine monitoring studies on the dissolved MMHg in the costal and open ocean seawaters.

Separation of methylmercury from biological samples for stable isotopic analysis

A new method of separation and pre-concentration of methylmercury (MeHg) species from total Hg in biological samples for determining the MeHg isotope composition.

Ecological risk assessment at the food web scale: A case study of a mercury contaminated oilfield

Mercury, particularly methylmercury, can accumulate through food webs and generate high risks for species at higher trophic levels. Inorganic mercury can be methylated into the organic species methylmercury if suitable reducing conditions exist, for example, in hotspots like oilfields. We developed a conceptual model to conduct an ecological risk assessment based on the food web structure of the Shengli oilfield area, China. The model can identify species at risk and elucidate the sources of risks according to their diet. A risk rating criteria was developed based on the food web structure to categorize the different levels of risks for different species. As expected, the results indicate increasing risks for the biota higher in the food web hierarchy. Grasshoppers were mostly at no risk throughout the study area, whereas grubs at southwest were at minimal risks due to local high Hg concentration in the soil. Mantises, which are insect predators, were also at minimal risk. Herbivorous birds with similar feeding habits than grasshoppers were at no risk, but omnivorous and carnivorous birds were at moderate risk. The conceptual model is a useful tool to improve pollution remediation and establish risk control strategies based on ecological risks of the food web rather than just Hg concentrations in the environment.

Effect of FeS on mercury behavior in mercury-contaminated stream sediment: A case study of Pohang Gumu Creek in South Korea

This study investigated mercury contamination with respect to the sediment characteristics in Gumu Creek near the Pohang Industrial Complex, South Korea. The contaminated sediment had high levels of Hg, exceeding 250 mg Hg/kg sediment at the sampling position, and high concentrations of iron, sulfur, and organic carbon under extreme anaerobic conditions. The anoxic condition of the sediment produced large amounts of FeS. Hg L3-edge EXAFS analysis revealed that FeS controlled the Hg species in the sediment mainly as β-HgS like precipitation or Hg-S complexation. We also speculated that the presence of FeS induced the abiotic reduction of Hg(II) to Hg(0) and consequently suppressed the formation of highly toxic methylated mercury species. The results obtained in this study are mostly consistent with those reported in previous studies of geochemical reactions of FeS in controlling Hg(II) under pure FeS mineral systems under laboratory scenarios. This study demonstrates that the laboratory controlled reaction scenarios can explain the field behavior of Hg in the contaminated anoxic sediment of the Gumu Creek site.

Direct Observation of Methylmercury and Auranofin Binding to Selenocysteine in Thioredoxin Reductase.

Selenoenzymes, containing a selenocysteine (Sec) residue, fulfill important roles in biology. The mammalian thioredoxin reductase selenoenzymes are key regulators of antioxidant defense and redox signaling and are inhibited by methylmercury species and by the gold-containing drug auranofin. It has been proposed that such inhibition is mediated by metal binding to Sec in the enzyme. However, direct structural observations of these classes of inhibitors binding to selenoenzymes have been few to date. Here we therefore have used extended X-ray absorption fine structure as a direct structural probe to investigate binding to the selenium site in recombinant rat thioredoxin reductase 1 (TrxR1). The results demonstrate for the first time the direct and complete binding of the metal atom of the inhibitors to the selenium atom in TrxR1 for both methylmercury and auranofin, indicating that TrxR1 inhibition indeed can be attributed to such direct metal-selenium binding.

Rethinking the Minamata Tragedy: What Mercury Species Was Really Responsible?

Industrial release of mercury into the local Minamata environment with consequent poisoning of local communities through contaminated fish and shellfish consumption is considered the classic case of environmental mercury poisoning. However, the mercury species in the factory effluent has proved controversial, originally suggested as inorganic, and more recently as methylmercury species. We used newly available methods to re-examine the cerebellum of historic Cat 717, which was fed factory effluent mixed with food to confirm the source. Synchrotron high-energy-resolution fluorescence detection-X-ray absorption spectroscopy revealed sulfur-bound organometallic mercury with a minor β-HgS phase. Density functional theory indicated energetic preference for α-mercuri-acetaldehyde as a waste product of aldehyde production. The consequences of this alternative species in the "classic" mercury poisoning should be re-evaluated.

Isolation of methylmercury using distillation and anion-exchange chromatography for isotopic analyses in natural matrices

The development of mercury (Hg) stable isotope measurements has enhanced the study of Hg sources and transformations in the environment. As a result of the mixing of inorganic Hg (iHg) and methylmercury (MeHg) species within organisms of the aquatic food web, understanding species-specific Hg stable isotopic compositions is of significant importance. The lack of MeHg isotope measurements is due to the analytical difficulty in the separation of the MeHg from the total Hg pool, with only a few methods having been tested over the past decade with varying degrees of success, and only a handful of environmentally relevant measurements. Here, we present a novel anion-exchange resin separation method using AG 1-X4 that further isolates MeHg from the sample matrix, following a distillation pretreatment, in order to obtain ambient MeHg stable isotopic compositions. This method avoids the use of organic reagents, does not require complex instrumentation, and is applicable across matrices. Separation tests across sediment, water, and biotic matrices showed acceptable recoveries (98 ± 5%, n = 54) and reproducible δ202Hg isotope results (2 SDs ≤ 0.15‰) down to 5 ng of MeHg. The measured MeHg pools in natural matrices, such as plankton and sediments, showed large deviations from the non-speciated total Hg measurement, indicating that there is an important isotopic shift during methylation that is not recorded by typical measurements, but is vital in order to assess sources of Hg during bioaccumulation. Graphical abstract.

An Endeavor in the Reaction-Based Approach to Fluorescent Probes for Biorelevant Analytes: Challenges and Achievements.

The promising features of fluorescence spectroscopy have inspired a quest for fluorescent probes for analysis and monitoring of molecular interactions in biochemical, medical, and environmental sciences. To overcome the competitive supramolecular interactions in aqueous media encountered with conventional molecular-recognition-based probes, the use of reaction-based probes that involve making or breaking of covalent bonds has emerged as a complementary sensing strategy to realize higher selectivity and sensitivity with larger spectroscopic changes. In spite of the enormous efforts, the development of reaction-based fluorescent probes meets with certain challenges in terms of their practical applications, demanding "intelligent design" of probes with an appropriate fluorophore attached to an efficient reactive moiety at the right place. This Account summarizes the results of our efforts made in the development and fine-tuning of reaction-based fluorescent probes toward those goals, classified by the type of analyte (anions, metal cations, and biomolecules) with notes on the challenges and achievements. The reaction-based approach was demonstrated to be powerful for the selective sensing of anions (cyanide and (amino)carboxylates) for the first time, and later it was extended to develop two-photon probes for bisulfite and fluoride ions. The reaction-based approach also enabled selective sensing of noble metal ions such as silver, gold, and palladium along with toxic (methyl)mercury species and paramagnetic copper ions. Furthermore, microscopic imaging and monitoring of biologically relevant species with reaction-based two-photon probes were explored for hydrogen sulfide, hypochlorous acid, formaldehyde, monoamine oxidaseenzyme, and ATP.

Dimethylmercury in Floodwaters of Mercury Contaminated Rice Paddies.

Dimethyl mercury (CH3HgCH3, DMeHg) has been observed in upwelling marine environments and the deep ocean. However, little is known about the occurrence and mechanisms of DMeHg formation in freshwater environments. In this study, concentrations of dissolved gaseous DMeHg were investigated in floodwaters of rice paddies in China that have been contaminated by mercury from mining. Values of DMeHg in rice paddies were compared with measurements from nearshore surface seawater in the Bohai Gulf. High concentrations of dissolved gaseous DMeHg occurred in rice paddies. Average DMeHg concentration was 12 ± 22 pg L-1 with range of 0.39 to 91 pg L-1 in rice paddies at Shuijing, China, a site impacted by an abandoned mercury mine. These concentrations are comparable to those previously observed in the deep seawater and coastal upwelling environments (2.3-115pg L-1). An alkaline environment was found to be necessary for DMeHg formation in rice paddies. Associated incubation experiments showed that production of DMeHg in paddy soil was limited by Hg availability. Although iron amendments accelerated the production of gaseous methylmercury (MeHg) species to floodwaters, available Hg2+ is crucial for this production in flooded rice paddies. These observations are the first to demonstrate the occurrence of DMeHg and reveal factors affecting DMeHg production in rice paddies. Given the high volatility of DMeHg, these measurements also suggest a source for observations of MeHg in atmospheric deposition and advance understanding of a potentially important aspect of the biogeochemical cycling of Hg.

Stratigraphic variations in the δ201Hg/δ199Hg ratio of mercury in sediment cores as historical records of methylmercury production in lakes

Total mercury (Hg) profiles of sediment cores from lakes serve as historical records of Hg pollution. They do not, however, provide information about temporal variations in the abundance of the toxic, preferentially bioaccumulated species methylmercury (CH3Hg+), whose production rate is largely a function of environmental variables that control the growth and activities of Hg-methylating and Hg-demethylating bacteria and the bioavailability of the inorganic Hg(II) from which CH3Hg+ is formed. Earlier studies showed that CH3Hg+ in freshwater food webs had anomalously high δ201Hg/δ199Hg ratios and, similarly, that the δ201Hg/δ199Hg ratio of Hg in a core from a severely Hg-polluted lake paralleled temporal changes in CH3Hg+ production. The present study was undertaken to test the hypothesis that variations in the δ201Hg/δ199Hg ratios of sediment cores from lakes reflect historical variations in CH3Hg+ production in the lakes. Core profiles of δ201Hg/δ199Hg ratios and total Hg concentrations from three widely separated, environmentally distinct temperate lakes polluted with Hg from different industrial sources, and one practically pristine Arctic lake, were examined, and changes attributable to known historical events were noted. Hg pollution led to increases in the δ201Hg/δ199Hg ratio, suggesting enhanced production of CH3Hg+, but the lakes showed different patterns of variation over time, implying the influence of site-specific environmental and biotic factors. In one lake the δ201Hg/δ199Hg ratio increased at the onset of each of three pollution episodes but peaked and then declined, suggesting a surge in methylation that was reversed by demethylation. In another lake, mercury pollution initiated a long-term upward trend in the isotope ratio, with secondary maxima and minima superimposed on it, implying a progressive increase in CH3Hg+, with successive shorter-term changes caused by fluctuations in methylation and demethylation rates. In the third lake, moderately elevated isotope ratios and one large maximum were associated with Hg contamination, but the maximum is attributable to accelerated eutrophication that intensified CH3Hg+ production. In the Arctic lake, the isotope ratio varied with climate change, decreasing during warming trends and increasing during cooling phases. These results constitute evidence that δ201Hg/δ199Hg ratios of sediment cores from lakes record historical variations in the net rate of CH3Hg+ production.

Simultaneous sub-picogram speciation of methylmercury and ethylmercury in caustic nuclear tank waste using direct aqueous propylation

Organomercury species are present at regulatory levels in the tanks at the Savannah River Site. Calibration of methylmercury and ethylmercury ranged three orders of magnitude, generating detection limits of 0.033 pg and 7.50 pg, respectively. Calibration verifications maintained 101 and 103% accuracy, respectively, with mean recovery from waste samples of 104%. Dilution volume was optimized to eliminate sample distillation, decreasing method runtime by 337% and reducing total instrumentation footprint by 60.4% compared with current standard methods. Compared with standard methods, this work represents a significant improvement in safety, efficiency, and reproducibility of organomercury speciation, particularly for industrial and nuclear analysis.