Alkyl Homologues Research Articles

HYDROCARBONS IN LITTORAL SEDIMENTS AND MARCH SOILS OF THE SOUTHWESTERN COAST OF THE BARENTS SEA

According to the results of GC-MS study of the composition and distribution of hydrocarbons (n-alkanes, isoprenoids, steranes, hopanes, polycyclic aromatic hydrocarbons (PAHs) and their alkyl homologues), the genesis, facies conditions of sedimentation, the degree of transformation of organic matter of bottom sediments and marching soils of the southwestern coast of the Barents Sea are characterized. The assessment of the toxicity levels of polyarenes on the biota inhabiting the tidal zones of the coast was carried out. Areas with increased anthropogenic load have been identified (littoral of the eastern Tana Fjord, the village of Kiberg, Abram Cape, the village of Mishukovo, the mouth of the Kulonga River, the apex part of the Yarnyshnaya Bay, Oscar Bay), indicating the unfavorable ecological state of the tidal zones of the Barents Sea coast.

Benzylic deuteration of alkylnitroaromatics via amine-base catalysed exchange with deuterium oxide.

This paper describes the deuterium-labelling of alkylnitroaromatics by base-catalysed exchange with deuterium oxide. As the alkyl protons alpha to the aromatic ring are the most acidic sites in the molecule, regioselective hydrogen isotope exchange at this benzylic location leads to a regiospecifically deuterated product. The exchange labelling takes place in good yields and with high atom% abundance in the presence of an appropriate nitrogen base. Alkylated 2,4-dinitrobenzenes deuterate at room temperature under catalysis by triethylamine, whilst alkylated 2-nitro- or 4-nitrobenzenes and related mono-nitroaromatics require higher temperatures and catalysis by 1,5-diazobicyclo[4.3.0]non-5-ene (DBN). The labelling reactions require an inert gas atmosphere, but otherwise are simple and high yielding with no obvious byproducts. Those compounds in which the benzylic protons are in an ortho-orientation with respect to the nitro group label somewhat more slowly than the analogues where there is a para relationship. In addition, higher alkyl homologues undergo benzylic deuteration at slower rates than methyl.

Seasonal and body size-dependent variability in the bioaccumulation of PAHs and their alkyl homologues in pearl oysters in the central Arabian Gulf.

Spatiotemporal concentration patterns for 19 parents and their alkyl homologues were measured in Pinctada radiata from 7 locations in the central Arabian Gulf around Qatar in the winter, spring and summer (2014-2015). The concentrations of PAHs ranged from 20 to 2240 (262±38.0ng·g-1 dw) with the highest occurrence in the Doha harbor (738.4±197.3ng·g-1 dw) and the lowest in the west coast of Qatar (48.3±5.8ng·g-1 dw). Residual PAHs in the oysters were about two times higher in winter than in spring and summer (P<0.05). PAHs in oysters are dominated by 2 and 3 rings PAHs and their alkyls. Alkylated PAHs (APAHs) comprised >55% of the ΣPAHs. Statistically significant differences in PAHs profiles among oysters were due in part to differences in lipid contents and shell biometrics. Principal component analysis (PCA) and diagnostic ratios for sources identifications suggested that PAHs accumulations in oysters were due to petrogenic and fuel combustion.

Fates of petroleum during the deepwater horizon oil spill: A chemistry perspective

We describe the initial bulk and compound specific composition of the liquid oil spilled during the Deepwater Horizon (DwH) disaster. The emphasis is on the target hydrocarbon compounds typically found in highest concentrations and on those of concern from a toxicological perspective (i.e., the target normal alkanes and isoprenoids, and PAHs on U.S. Environmental Protection Agency’s (EPA) priority list with their alkyl homolog compounds), and/or those relevant for forensic fingerprinting of spill residues (i.e., sulfur containing PAHs and biomarker compounds). Weathering changed the oil’s composition in various environmental compartments. These compositional changes and potential environmental impacts of the remaining weathered residues are presented in this paper. Biodegradation occurred in both surface and subsurface environments while photooxidation primarily modified and removed hydrocarbons in floating oil slicks. The volatile, soluble and highly labile C1 to C10 hydrocarbons were rapidly degraded in the water column and/or emitted to the atmosphere (evaporation). The semi-volatile hydrocarbons (labile C10 to C25) that remained in the water column and floating oil on the water’s surface were lost from oil residues during weathering. The heavy nonvolatile and insoluble hydrocarbons (recalcitrant C25+) were least affected by initial weathering processes in 2010. The composition of the residual oil fraction in surface floating oil was further altered by the addition of oil soluble oxy hydrocarbons produced from photooxidation. During 2011 and 2012 the resulting highly insoluble recalcitrant C25+ oily residues remained on the shorelines, bottom sediments, or bound to suspended particulates in the water column, with detectable residues mostly returning to near pre-spill levels by 2015 to 2020. Some recalcitrant oil residues can still be found at various locations, including some coastal environments (e.g., marshes), or deep-water sediments, at very low levels, ten years after the spill.

Alkylation of Benz[a]anthracene Affects Toxicity to Early-Life Stage Zebrafish and In Vitro Aryl Hydrocarbon Receptor 2 Transactivation in a Position-Dependent Manner.

Polycyclic aromatic hydrocarbons (PAHs) are structurally diverse organic chemicals that can have adverse effects on the health of fishes through activation of aryl hydrocarbon receptor 2 (AhR2). They are ubiquitous in the environment, but alkyl PAHs are more abundant in some environmental matrices. However, relatively little is known regarding the effects of alkylation on the toxicity of PAHs to fishes in vivo and how this relates to potency for activation of AhR2 in vitro. Therefore, the objectives of the present study were to determine the toxicity of benz[a]anthracene and three alkylated homologs representing various alkylation positions to early life stages of zebrafish (Danio rerio) and to assess the potency of each for activation of the zebrafish AhR2 in a standardized in vitro AhR transactivation assay. Exposure of embryos to each of the PAHs caused a dose-dependent increase in mortality and malformations characteristic of AhR2 activation. Each alkyl homolog had in vivo toxicities and in vitro AhR2 activation potencies different from those of the parent PAH in a position-dependent manner. However, there was no statistically significant linear relationship between responses measured in these assays. The results suggest a need for further investigation into the effect of alkylation on the toxicity of PAHs to fishes and greater consideration of the contribution of alkylated homologs in ecological risk assessments. Environ Toxicol Chem 2022;41:1993-2002. © 2022 SETAC.

Synthesis of 3'-O-Alkyl Homologues and a Biotin Probe of Isorhamnetin and Evaluation of Cytotoxic Efficacy on Cancer Cells.

Isorhamnetin is a natural flavonoid which shows a variety of biological activities such as antioxidant, anti-inflammatory and antitumor. In order to identify the cellular binding protein of isorhamnetin as potential anti-cancer target, we first synthesized 3'-O-substituted quercetin as isorhamnetin homologues and evaluated the growth inhibitory activity of these derivatives on breast, colon and prostate cancer cell lines. The preliminary results showed that the 3'-O modification did not affect the cytotoxic activity of the scaffold. Analysis of the co-crystal structure and the docking pose of isorhamnetin with reported binding protein of isorhamnetin or quercetin indicated the 3'-O-substitution groups located outside of the binding pocket, which is in accordance with activity of 3'-O derivatives. Then a biotin conjugate of isorhamnetin with a tetraethylene glycol (PEG)4 linker at the 3' position was synthesized and the resulting probe retained the anti-proliferative activity on cancer cell lines, while the cellular fluorescence analysis showed the distribution of probe inside the cells which indicated the probe had limited cell permeability. Finally, pull down assay both in situ inside cells and in the cell lysates indicated the isorhamnetin biotin probe was capable of protein labeling in cell lysates. These findings provide the isorhamnetin 3'-O-biotin probe as a tool to reveal the target proteins of isorhamnetin.

Parent and alkylated PAHs profiles in 11 petroleum fuels and lubricants: Application for oil spill accidents in the environment

Eleven types of petroleum fuels and lubricants including regular gasoline, premium gasoline, jet fuel, kerosene, light oil, bunker A, bunker A–white, bunker A–low sulfur, bunker C, quench oil and lubricant samples were analyzed for parent and alkylated polycyclic aromatic hydrocarbons (PAHs). Naphthalene was the predominant compound in gasolines, jet fuel and kerosene, constituting > 95% of the parent PAHs, whereas dibenzothiophene and other high molecular weight PAHs were predominant in bunker A and bunker C. PAH compositions in petroleum fuels differ because of differences in their refining temperatures and the boiling points of individual PAHs. Principal component analysis classified into four groups of petroleum fuels. Further, oil samples were clearly separated into five groups based on their ratios of select alkyl homologs (C0/(C0+C1) and C4/(C2+C4) naphthalenes): ‘gasolines’ ‘light oil’ ‘bunker oils’ ‘kerosene’ and ‘quench oil’. A wide variety and detailed profiles of PAHs in petroleum fuels and lubricants in this study can be used for baseline data in oil fingerprinting analyses to identify the potential source of oil spill accidents in the environment.

Chemical characterization of particulate organic matter from commercial restaurants: Alkyl PAHs as new tracers for cooking

Cooking is one of the primary sources of particulate organic matter (POM) in urban environments. Numerous experiments have been performed to investigate the composition of POM generated during cooking. However, there still remain substantial uncertainties in our knowledge regarding the emission characteristics of alkyl polycyclic aromatic hydrocarbons (PAHs) from cooking. In addition, previous studies have selected several tracers for Chinese cooking; however, these results were acquired based on observations in the Pearl River Delta region of China, and only four of the eight Chinese cooking styles were tested. Therefore, the organic compositions of the PM2.5 emitted from four Chinese cooking restaurants in different cities are examined to investigate the emission characteristics of alkyl PAH and to verify whether the selected tracers vary with geographical location and cooking styles. In this study, C1- and C2-phenanthrenes/anthracenes, and C1-pyrenes were detected in the PM2.5 from the four tested restaurants, but the concentrations of these PAH alkyl homologues were all at low levels, and also much lower than the corresponding parent PAHs. However, the distribution pattern of the alkyl PAHs in the cooking fumes was significantly different from that in the PM from other emission sources. Additionally, some candidate tracers for cooking such as levoglucosan were less influenced by cooking styles or geographical location. Thus, these alkyl PAHs in conjunction with other specific tracers for cooking were utilized to estimate the contribution of cooking to ambient organic carbon. The results showed that the estimates from the chemical mass balance model that includes alkyl PAHs will be higher than the model that does not, and in the case of high alkyl PAHs ambient concentrations, the model that includes alkyl PAHs will provide more reasonable results.

Homologous alkyl side-chain diphosphonate inhibitors for the corrosion protection of carbon steels

The interactions of six homologous diphosphonate additives, methylamine-N,N-bis(methylenephosphonate) (MBMP, C1-D), ethylamine-N,N-bis(methylenephosphonate) (EBMP, C2-D), butylamine-N,N-bis(methylenephosphonate) (BBMP, C4-D), hexylamine-N,N-bis(methylenephosphonate) (HBMP, C6-D), octylamine-N,N-bis(methylenephosphonate) (OBMP, C8-D), dodecylamine-N,N-bis(methylenephosphonate) (DBMP, C12-D), with carbon steel surfaces are studied by XPS at pH = 3.0. Structurally, all additives possess two methylenephosphonate moieties connected to a single N atom. The third substituent on N is a non-polar, variable-length alkyl chain, –(CH2)xCH3, where x = 0 (C1-D), 1 (C2-D), 3 (C4-D), 5 (C6-D), 7 (C8-D), and 11 (C12-D). XPS studies (on pristine solid diphosphonate samples and also on carbon steel specimens, immersed in aqueous solutions), indicate significant deprotonation of the diphosphonic acid molecules upon interaction with the metallic surface. They also prove that this surface interaction results in adsorption on the surface via the deprotonated phosphonic acid moieties. The adsorption of inhibitors on the metal surface was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. The changes detected in the charge transfer resistance (Rct) and constant phase element (CPE) independently confirm inhibitor adsorption on metal surface. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy was used to investigate the nature of deposited film. Small alkyl chain diphosphonates (C1-D, C2-D and C4-D) exhibited lower corrosion resistance due to the thin, porous and/or incomplete layer formed on carbon steel surface. Longer alkyl chain molecules (C6-D, C8-D and C12-D) were found to adsorb more efficiently and form a more organized and thicker layer. The best results were obtained in the case of C8-D (lower corrosion current, higher Rct and surface coverage). In the presence of C8-D the corrosion rate was reduced by a factor of 6.

Geochemical evaluation of aliphatic and aromatic hydrocarbons in Palaeogene source rocks from the Latrobe Group, Gippsland Basin, Australia

Twenty-seven hydrocarbon source rocks from the Proteacidites asperopolus, Malvacipollis diversus and Lygistepollenites balmei biozones, Palaeogene Latrobe Group in the Gippsland Basin were analysed using gas chromatography-mass spectrometry. Based on the molecular geochemistry of the aliphatic and aromatic fractions, together with bulk geochemical data (including Rock-Eval pyrolysis and total organic carbon contents), the thermal maturity, palaeoenvironments, and organic matter source of these Palaeogene samples were systematically evaluated. The results provide a useful comparison with those from Upper Cretaceous source rocks in the Gippsland Basin (Jiang and George, 2018, 2019). Similar to the Upper Cretaceous rocks, the aliphatic hydrocarbons in the Paleogene samples are mainly comprised of n-alkanes, isoprenoids, terpanes, hopanes and steranes. The aromatic hydrocarbons are dominated by naphthalene, phenanthrene, anthracene, fluorene, dibenzofuran, dibenzothiophene and their alkyl homologues. Other aromatic hydrocarbons detected include land plant-derived compounds (e.g. retene, methylretenes, cadalene, simonellite, etc), and combustion-derived compounds (e.g. chrysene, pyrene, picene, benzo[b]fluoranthene, benzo[a]anthracene, etc). These 4- to 6-ring polycyclic aromatic hydrocarbons are more abundant in the Paleogene samples compared to the Upper Cretaceous rocks. Biomarker and aromatic hydrocarbon distributions indicate that the Proteacidites asperopolus and Malvacipollis diversus samples are immature or are in the early stage of the oil generation window, while the Lygistepollenites balmei samples correspond to the low maturity to mature stage. The samples were all deposited under sub-oxic to oxic conditions in fresh water with low salinity, possibly in a lacustrine depositional environment. The organic matter inputs are from plankton/algae and higher land plants, but are dominated by organic matter with a terrigenous origin.

Analysis and Evaluation of Contamination Status of Polycyclic Aromatic Hydrocarbons (PAHs) in Settled House and Road Dust Samples from Hanoi

Analysis and Evaluation of Contamination Status of Polycyclic Aromatic Hydrocarbons (PAHs) in Settled House and Road Dust Samples from Hanoi

Complex Patterns of Cannabinoid Alkyl Side-Chain Inheritance in Cannabis

The cannabinoid alkyl side-chain represents an important pharmacophore, where genetic targeting of alkyl homologs has the potential to provide enhanced forms of Cannabis for biopharmaceutical manufacture. Delta(9)-tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) synthase genes govern dicyclic (CBDA) and tricyclic (THCA) cannabinoid composition. However, the inheritance of alkyl side-chain length has not been resolved, and few studies have investigated the contributions and interactions between cannabinoid synthesis pathway loci. To examine the inheritance of chemical phenotype (chemotype), THCAS and CBDAS genotypes were scored and alkyl cannabinoid segregation analysed in 210 F2 progeny derived from a cross between two Cannabis chemotypes divergent for alkyl and cyclic cannabinoids. Inheritance patterns of F2 progeny were non-Gaussian and deviated from Mendelian expectations. However, discrete alkyl cannabinoid segregation patterns consistent with digenic as well as epistatic modes of inheritance were observed among F2THCAS and CBDAS genotypes. These results suggest linkage between cannabinoid pathway loci and highlight the need for further detailed characterisation of cannabinoid inheritance to facilitate metabolic engineering of chemically elite germplasm.

Phenoxy‐Alkyl Maleates as Phase‐Selective Organogelators for Gelation of Edible Oils

Phase selective gelation may solve environmental problems such as water pollution and fire accidents during oil storage, a major problem for aquatic bodies. The objective of this work is to synthesize a series of phenoxy‐alkyl maleates (n‐PAM) oleogelators with homologous alkyl chain lengths for efficient phase selective gelation. The n‐PAM molecules are found to form oleogel in various edible oils among which sunflower oil shows best gelation. The gelation behavior increases with an increase in alkyl chain length of the n‐PAM gelators as observed from their low minimum gelation concentration (MGC) values. Oleogels thermal stability is examine through tube inversion method and differential scanning calorimetry (DSC). The rheological studies suggest that the oleogel of sunflower oil is mechanically stable and show typical viscoelastic properties. The field emission scanning electron microscopy (FE‐SEM) study of the gels shows sheet‐like morphology. Furthermore, the n‐PAM gelators exhibit quick phase selective gelation of edible oils at low MGC. Both the edible oil and gelator are quantitatively regained from recovered oleogel by employing the vacuum distillation. It is believed that these n‐PAMs could aid in reducing the environmental impacts of oil spills.Practical Applications: The phenoxy‐alkyl maleates gelators present in the MS show gelation ability in various edible oils at low minimum gelation concentration. These molecules also form efficient phase selective gelation with edible oils. Both oil and gelator can be recovered through vacuum distillation and gelator can be reused multiple times. Thus, all these advantages strongly point that out their bright future, in particular in edible oil spill recovery, could aid in reducing the environmental impacts from oil spills.Herein, the synthesized phenoxy alkyl maleate derivatives are reported as separators of edible oil from the oil‐water biphasic mixture. Initially, the gelator is solubilized in the biphasic mixture by heating. Later, gelation ability is observed by tube inversion method. From the phase selective gel, oil and gelator are separated through a distillation method. The recovered gelator can be reused in oil recovery process. This application may find use in oil recovery from waste plant of edible oil industries.

Spatio-temporal distribution and sources identifications of polycyclic aromatic hydrocarbons and their alkyl homolog in surface sediments in the central Arabian Gulf

The quantitative analysis of 18 parents and their alkyl homologs was performed in sediment samples from the central Arabian Gulf (Gulf) around Qatar Peninsula in six sequential seasons, winter 2014 to spring 2015, at 21 locations with a water depth range of 1.5–60 m. PAHs distribution was patchy with higher concentrations found inside semi-enclosed coastal areas like harbors and bays. The mean PAHs concentration was 112 ng·g−1 dry weight with a range of 0.6 to 1560 ng·g−1 and a variability coefficient of 2.4. The PAHs mean concentration was highest in the winter by a factor of 5 compared to mean summer concentration. A significant seasonal variability in the concentrations of ∑PAHs is mainly attributed to variability in the concentrations of the low molecular weight PAHs fraction and the less alkylated PAHs. Alkylated-PAHs were the most dominant PAHs comprising about 50% of the ∑PAHs, and with about 6 times higher than the mean concentrations in the winter compared to the mean summer concentration. The LPAHs concentrations correlated negatively with temperature and ∑PAHs correlated positively with % clay. Principal component analysis was used to identify sources of PAHs. PAHs in the Gulf have mixed sources with an estimated 57% from petroleum and 43% from pyrogenic sources. Coastal water hydrodynamics and lateral transport processes affect the distribution and composition of PAHs in the central Gulf.

Synthesis of [13C₃]-B6 Vitamers Labelled at Three Consecutive Positions Starting from [13C₃]-Propionic Acid.

[13C3]-labelled vitamers (PN, PL and PM) of the B6 group were prepared starting from [13C3]-propionic acid. [13C3]-PN was synthesized in ten linear steps with an overall yield of 17%. Hereby, higher alkyl homologues of involved esters showed a positive impact on the reaction outcome of the intermediates in the chosen synthetic route. Oxidation of [13C3]-PN to [13C3]-PL was undertaken using potassium permanganate and methylamine followed by acid hydrolysis of the imine derivative. [13C3]-PM could be prepared from the oxime derivative of [13C3]-PN by hydrogenation with palladium.

Calculation of the Surface Tension of Ordinary Organic and Ionic Liquids by Means of a Generally Applicable Computer Algorithm Based on the Group-Additivity Method.

The calculation of the surface tension of ordinary organic and ionic liquids, based on a computer algorithm applying a refined group-additivity method, is presented. The refinement consists of the complete breakdown of the molecules into their constituting atoms, further distinguishing them by their immediate neighbour atoms and bond constitution. The evaluation of the atom-groups’ contributions was carried out by means of a fast Gauss-Seidel fitting method, founded upon the experimental data of 1893 compounds from literature. The result has been tested for plausibility using a 10-fold cross-validation (cv) procedure. The direct calculation and the cv test proved the applicability of the present method by the close similarity and excellent goodness of fit R2 and Q2 of 0.9039 and 0.8823, respectively. The respective standard deviations are ±1.99 and ±2.16 dyn/cm. Some correlation peculiarities have been observed in a series of ordinary and ionic liquids with homologous alkyl chains, as well as with di- and trihydroxy-groups-containing liquids, which have been discussed in detail, exhibiting the limit of the present method.

The use of dihexyldithiocarbamate in reverse-phase HPLC of metal chelates

Dialkyldithiocarbamates have long been used as chelating agents in reverse-phase HPLC of transition metals. In the previous study, an alkyl homolog of this type of ligand, namely dihexyldithiocarbamate (DHDTC), was synthesized and characterized. The use of this particular ligand in the revese-phase HPLC of some selected transition metal ions is now reported for the first time. The mobile phase comprising of the flow rate and of the detection, in the separation of the metal chelates of Cd (II), Fe (III), Cu (II), and Co (III), were investigated on a C-18 column. The results showed that dihexylditiocarbamate could be used for separating Cd (II), Fe(III), Cu(II), and Co(III). Therefore, it could be used in simultaneous analysis.

Polycyclic aromatic hydrocarbon in solid reservoir bitumen from the central Sichuan Basin

ABSTRACTPolycyclic aromatic hydrocarbons in solid bitumen from the central Sichuan Basin have been investigated. Several compounds including fluoranthene (Fl), pyrene (Py), benz[a]anthracene (BaA), chrysene (Chy), benzofluoranthenes (BFl), and benzopyrenes (BePy) are found to have enhanced concentrations in several samples. Abnormally high values of the Fl/(Fl + Py), BaA/(BaA + Chy), and BFl/(BFl + BPy) ratios are also observed. In addition, they have parent aromatic compounds that are considerably more abundant than their alkyl homologues. These features indicate that formation of the solid bitumen is probably related to abnormal heating, which may be induced by hydrothermal activity.

Multidimensional Gas Chromatography–Mass Spectrometry Method for Fingerprinting Polycyclic Aromatic Hydrocarbons and Their Alkyl-Homologs in Crude Oil

ABSTRACTThe composition of polycyclic aromatic hydrocarbons in crude oil is usually too complex to use standard capillary gas chromatography to separate all of the components. In this study, a multidimensional gas chromatography–mass spectrometry (GC-MS) technique was used to analyze polycyclic aromatic hydrocarbon fractions of crude oil collected from the Dongying oil field in the Bohai Sea. A DB-17MS column (30 m × 0.25 mm × 0.25 µm) was used as a prefractionating column and only selected heart-cuts were transferred to the second chromatographic dimension (HP-5MS, 15 m × 0.25 mm × 0.25 µm) by a pressure-adjusted continual flow-type switching device for quantification of the polycyclic aromatic hydrocarbons. The chromatographic elements and parameters, such as detector selection and column combinations, were optimized. Naphthalene, phenanthrene, fluorene, dibenzothiophene, chrysene, and their C1–C4 alkyl homologs were identified. The profile of the polycyclic aromatic hydrocarbons obtained using the multidimensional GC-MS method was compared with the results obtained by traditional one-dimensional GC-MS.

73 - Chemical Trapping and Characterization of small Oxoacids of Sulfur (SOS) and Selenium (SOSe) Generated in Aqueous Oxidations of H2S and H2Se

Small oxoacids of sulfur (SOS) are elusive molecules like sulfenic acid, HSOH, and sulfinic acid, HS(O)OH, generated by oxidation of hydro-gen sulfide, H2S, in aqueous solution. Like their alkyl homologs, SOS may exhibit both nucleophilic and electrophilic reactivity due to interconversion between S(II) and S(IV) tautomers. We find that SOS may be trapped in situ by derivate-ization with nucleophilic and electrophilic trapping agents and then characterized by high resolution LC/MS. Herein, we compare SOS formation from H2S oxidation by a variety of biologically relevant oxidants. Analogous small oxoacids of selenium, SOSe, are generated during aqueous oxidations of hydrogen selenide (H2Se). These SOS and SOSe species appear relatively long lived in aqueous solution, and thus may be involved in the observed physiological effects derived from H2S and potentially H2Se.