Ratio Mass Spectrometry Method Research Articles

Successive and automated stable isotope analysis of CO2 , CH4 and N2 O paving the way for unmanned aerial vehicle-based sampling.

RationaleMeasurement of greenhouse gas (GHG) concentrations and isotopic compositions in the atmosphere is a valuable tool for predicting their sources and sinks, and ultimately how they affect Earth's climate. Easy access to unmanned aerial vehicles (UAVs) has opened up new opportunities for remote gas sampling and provides logistical and economic opportunities to improve GHG measurements.MethodsThis study presents synchronized gas chromatography/isotope ratio mass spectrometry (GC/IRMS) methods for the analysis of atmospheric gas samples (20‐mL glass vessels) to determine the stable isotope ratios and concentrations of CO2, CH4 and N2O. To our knowledge there is no comprehensive GC/IRMS setup for successive measurement of CO2, CH4 and N2O analysis meshed with a UAV‐based sampling system. The systems were built using off‐the‐shelf instruments augmented with minor modifications.ResultsThe precision of working gas standards achieved for δ13C and δ18O values of CO2 was 0.2‰ and 0.3‰, respectively. The mid‐term precision for δ13C and δ15N values of CH4 and N2O working gas standards was 0.4‰ and 0.3‰, respectively. Injection quantities of working gas standards indicated a relative standard deviation of 1%, 5% and 5% for CO2, CH4 and N2O, respectively. Measurements of atmospheric air samples demonstrated a standard deviation of 0.3‰ and 0.4‰ for the δ13C and δ18O values, respectively, of CO2, 0.5‰ for the δ13C value of CH4 and 0.3‰ for the δ15N value of N2O.ConclusionsResults from internal calibration and field sample analysis, as well as comparisons with similar measurement techniques, suggest that the method is applicable for the stable isotope analysis of these three important GHGs. In contrast to previously reported findings, the presented method enables successive analysis of all three GHGs from a single ambient atmospheric gas sample.

Carbon isotope ratio of endogenous urinary steroids of the Cuban population of athletes studied for doping purposes.

The aim of this work was to validate the gas chromatography/combustion/isotope ratio mass spectrometry method in Havana Antidoping Laboratory and verify its implementation with a study of the Cuban population. The method was precise and accurate inside the linear working range; the limit of quantification and the uncertainty were compliant with TD2019IRMS. The study of the Cuban population showed no differences in δ13 C values between females and males. Only three values of Δδ13 C showed significant differences between sexes (PD-T, OHA-T, and 11-keto-Et-T). The values of δ13 C between -17.8‰ and -21.2‰ (upper and lower limits based on normal distribution) were consistent with other populations where C4 plant derivatives prevail in the diet.

Carbon isotopic characterization of prednisolone and prednisone pharmaceutical formulations: Implications in antidoping analysis.

Twenty-two pharmaceutical formulations containing prednisolone or prednisone commercially available in Italy, Belgium, Spain, Brazil, and India were analyzed through a specific gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) method. All of them showed typical non-endogenous δ13 C values, except for the Belgian nasal spray, Sofrasolone®, with a less depleted 13 C content (-17.84 ± 0.18‰). Observational studies were performed on two volunteers in therapy with Sofrasolone® to confirm the applicability of the method and to suggest adequate interpretation criteria also in the case of drugs with less negative δ13 C values. Urine samples were collected before, during, and within the 36 hours after the administration of the spray. Both δ13 C values and urinary concentrations of prednisolone and prednisone were evaluated. All samples were subjected to an adequate pre-treatment (enzymatic hydrolysis, liquid/liquid extraction, and two sequential HPLC steps) before injection to the GC-C-IRMS instrument, according to the method recently developed and validated in our laboratory. Pregnanediol (PD), tetrahydro-11-deoxycortisol (THS), and pregnanetriol (PT) were selected as endogenous reference compounds (ERC). The excretion profile was estimated through liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method used routinely for the quali-quantitative detection of glucocorticoids. δ13 C values and urinary levels of prednisolone and prednisone were also determined after the intake of one single vial of Sintredius®, a prednisolone oral formulation with a conventional more negative δ13 C value (-29.28 ± 0.25‰). Finally, the potential masking effect that combined therapy with Sofrasolone® and Sintredius® could induce on the IRMS findings was investigated.

Chemometric authentication of Pu'er teas in terms of multielement stable isotope ratios analysis by EA-IRMS and ICP-MS.

In this work, the stable isotope ratios of carbon, nitrogen, hydrogen, oxygen, and mineral elements and their stoichiometric methods were examined as possible factors that could certify Chinese tea based on its production years. A total of 43 multi-element stable isotope ratios of Xiangzhujing Pu’er tea in five production years were determined through inductively coupled plasma mass spectrometry (ICP-MS) and elemental analyzer-isotope ratio mass spectrometry (EA-IRMS) methods. Two unsupervised learning techniques (principal component analysis and hierarchical clustering analysis) and three supervised learning techniques (partial least squares discriminant analysis [PLS-DA], back-propagation artificial neural network [BP-ANN], and linear discriminant analysis [LDA]) were used on the basis of 18 statistically significant multi-elemental stable isotope ratios to build authentication models for Pu’er tea. The clustering abilities of the two unsupervised learning methods were worse than those of the three supervised learning methods. The three supervised models correctly separated the corresponding production years of the samples. The authentication performance was obtained through BP-ANN and LDA, with 100% recognition and prediction abilities, which were better than those of PLS-DA. δD, δ13C, and 154Sm/152Sm were determined as the markers for the accurate authentication of Pu’er tea in different production years. The profiles of multi-element stable isotope ratios obtained via ICP-MS and EA-IRMS with chemometric methods could serve as potential and powerful factors for authenticating Chinese tea in different production years. This study contributed to the generalization of the use of multi-elemental stable isotope ratio fingerprinting as a promising tool for testing the authenticity of tea worldwide.

Impact of Land-Use Change on Soil Carbon Dynamics in Tropical Peatland, West Kalimantan- Indonesia

The conversion of tropical peat forest to other land uses can reduce organic carbon (C) and stable C isotope (δ13C) of peat soil. This research aimed at analyzing the soil organic-C and δ13C of peatland with respect to maturity (fibric, hemic and sapric) in five types of peatland use, which included primary peat forest, secondary peat forest, shrubs, oil palm plantations, and cornfield in West Kalimantan. Analysis of peat soil samples includes organic C with Loss in ignition method and δ13C using an isotope ratio mass spectrometry(IRMS) method. Organic-C at fibric was higher than hemic and sapric, respectively (57.2%, 57.0%, 56.4%), meanwhile, organic-C was the highest on primary peat forest, followed by on secondary peat forest, oil palm plantation, cornfield, and shrubs, respectively 57.1%, 57.0%, 56.4%, 56.0%. The cause of increasing and decreasing organic C and δ13C due to land-use change due to changes in vegetation, burning during tillage, and age of organic matter of peat soil. This condition causes the opening of natural peat ecosystems and changes in anaerobic to aerobic conditions.

Development and validation of a fast gas chromatography combustion isotope ratio mass spectrometry method for the detection of epiandrosterone sulfate in urine.

In doping control, to confirm the exogenous origin of exogenously administered anabolic androgenic steroids (AAS), a gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) analysis is performed. Recently published work suggests that epiandrosterone sulfate (EpiAS) is a promising IRMS target compound for the detection of AAS, capable of prolonging the detection window. However, EpiAS is only excreted in urine in its sulfoconjugated form, while all other IRMS target compounds are excreted glucuronidated, meaning that EpiAS cannot be incorporated in the existing IRMS methods. A separate extensive sample preparation needs to be performed on this compound with a different hydrolysis and extraction procedure and a different liquid chromatography (LC) clean-up. The current work presents a new, fast, and easy to implement EpiAS IRMS method. The approach was based on the direct GC analysis of non-hydrolyzed EpiAS, making the solid phase extraction, hydrolysis, and acetylation step redundant. Sample preparation consisted of a simple liquid-liquid extraction, followed by LC fraction collection. A population study was performed to check compliance with the criteria drafted by the World Anti-Doping Agency (WADA). To verify the applicability of the developed approach, the method was applied to the samples of four administration studies (i.e. dehydroepiandrosterone (DHEA), testosterone gel (T gel), androstenedione (ADION), and intramuscular testosterone undecanoate. In contrast to previously published data, the strength of EpiAS as the target compound and the prolongation of the detection window in comparison with the conventional IRMS target compounds was less pronounced.

Detecting the misuse of 7-oxo-DHEA by means of carbon isotope ratio mass spectrometry in doping control analysis.

The misuse of 7-oxo-DHEA (3β-hydroxyandrost-5-ene-7,17-dione) is prohibited according to the World Anti-Doping Agency (WADA) code. Nevertheless, it is easily available as a dietary supplement and from black market sources. In two recent doping control samples, significant amounts of its main metabolite 7β-OH-DHEA were identified, necessitating further investigations. As both 7-oxo-DHEA and 7β-OH-DHEA are endogenously produced steroids and no concentration thresholds applicable to routine doping controls exist, the development and validation of a carbon isotope ratio (CIR) mass spectrometry method ha been desirable. Excretion studies encompassing 7-oxo-DHEA, 7-oxo-DHEA-acetate, and in-house deuterated 7-oxo-DHEA were conducted and evaluated with regard to urinary CIR and potential new metabolites of 7-oxo-DHEA. Numerous urinary metabolites were identified, some of which have not been reported before, while others corroborate earlier findings on the metabolism of 7-oxo-DHEA. The CIRs of both 7-oxo-DHEA and 7β-OH-DHEA were significantly influenced for more than 50 h after a single oral dose of 100 mg, and a novel metabolite (5α-androstane-3β,7β-diol-17-one) was found to prolong this detection time window by approximately 25 h. Applying the validated method to routine doping control specimens presenting atypically high urinary 7β-OH-DHEA levels clearly demonstrated the exogenous origin of 7-oxo-DHEA and 7β-OH-DHEA. As established for other endogenously produced steroids such as testosterone, the CIR allows for a clear differentiation between endo- and exogenous sources of 7-oxo-DHEA and 7β-OH-DHEA. The novel metabolites detected after administration may help to improve the detection of 7-oxo-DHEA misuse and simplify its detection in doping control specimens.

Natal origin of the invasive biosecurity pest, brown marmorated stink bug (Halyomorpha halys: Penatomidae), determined by dual-element stable isotope-ratio mass spectrometry.

BACKGROUNDPost‐border detection of a single brown marmorated stink bug (BMSB) in New Zealand warranted a biosecurity response, the nature of which would be influenced by its status as part of an established population or as a new arrival. Stable isotope analysis has the potential to determine natal origins, but is difficult to achieve for samples as small as a single insect. Here an analytical modification to measure small samples was successfully trialled as a means to supply evidence as to the local or exotic natal origin of the intercepted BMSB specimen.RESULTSSufficient analytical sensitivity was achieved using a modified isotope ratio mass spectrometry method, involving thermolysis and carbon monoxide cryofocusing, to enable the simultaneous analysis of δ2H and δ18O from wings of the post‐border BMSB sample. The values were much lower than those of the New Zealand green vegetable bug, used as a local reference. However, they fell within the range of those for BMSB of Northern Hemisphere origin intercepted at the New Zealand border over the same time period, specifically overlapping with the USA and Italy, but not China.CONCLUSIONThe isotope signature of the post‐border detected BMSB suggested a significantly cooler climate than the North Island of New Zealand, indicating that it was a new arrival and did not represent an established population. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Development and validation of a method to confirm the exogenous origin of prednisone and prednisolone by GC-C-IRMS.

Prednisone and prednisolone are two anti-inflammatory steroidal drugs listed by the World Anti-Doping Agency (WADA) within the class of glucocorticoids, which are prohibited "in competition" and when administered systemically. Their presence in collected urine samples may be attributed, if no exogenous administration has occurred, to an in situ microbial formation from endogenous steroids. In this work, a gas chromatography coupled to carbon isotope ratio mass spectrometry (GC-C-IRMS) method was developed and validated to distinguish an exogenous origin from an endogenous one. Eight prednisone/prednisolone pharmaceutical preparations commercially available in Italy were analysed to establish an exogenous δ13 C value reference range (-28.96 ± 0.39‰). No more than 25 mL of urine was processed and no derivatization nor intentional steroids structure modifications were performed before the GC-C-IRMS analysis. A first HPLC purification step was set up to isolate the three endogenous reference compounds (ERCs) selected (tetrahydro-11-deoxycortisol (THS), pregnanediol (PD), and pregnanetriol (PT)), while a second LC purification was necessary to separate prednisone from prednisolone. In the GC-C-IRMS analysis, two different GC run methods were set up to guarantee better sensitivity and selectivity for each compound. Both prednisone and prednisolone showed signals (m/z 44) with amplitudes within the method linearity range to a lower urinary concentration of 20 ng/mL (< WADA reporting level, 30 ng/mL). The method was fully validated according to WADA requirements. As a proof of concept, urine samples collected from two excretion studies in healthy male volunteers, after a prednisone or prednisolone administration, were analysed by the proposed method, demonstrating its applicability for the analysis of real samples.

Geographical discrimination of garlic (Allium Sativum L.) based on Stable isotope ratio analysis coupled with statistical methods: The Italian case study

Stable isotope ratio analysis of the major bioelements (δ2H, δ13C, δ15N, δ18O, δ34S), considered for the first time as a whole, was used to attempt a geographical characterization of red garlic (Allium sativum L.) cultivated throughout different Italian territories (Abruzzo, Lazio and Sicily). Up to now, no official methods are available to determine the geographical origin of this type of product. In this context, the Isotope Ratio Mass Spectrometry method (IRMS) represents a powerful analytical technique. The characteristic ranges of variability of the five isotope ratios in 56 red Italian garlic samples are here presented as well as their relationships. The geographical origin has some influence over the different ratios, although their data distribution shows some overlap when Principal Component Analysis (PCA) is applied. In spite of the relative closeness of the sampling sites, a model with very good predictive performance of the geographical classification was achieved byLinear Discriminant Analysis (LDA) and k-nearest neighbours (k-NN) method. Moreover, preliminary class modelling based on Soft Independent Modelling of Class Analogy (SIMCA) supports the ability of stable isotope ratios analysis for the geographical traceability of garlic.

Carbon isotopic analysis of reactive organic matter using a new pyrolysis-cryotrapping-isotope ratio mass spectrometry method: The isotope variation of organic matter within the S1 and S2 peaks of Rock-Eval

The source material, the mode of photosynthesis, the organic matter (OM) type, the paleoenvironmental conditions and thermal degradation all determine the isotopic composition of OM. This study presents a novel analytical technique and demonstrates its potential to enhance the understanding of the preservation and maturation-related isotopic compositional changes in OM from different paleoenvironments. A new Rock-Eval type pyrolysis coupled to isotope ratio mass spectrometry (py-IRMS) method has been developed to monitor the isotopic changes during Rock-Eval type pyrolysis while simultaneously recording pyrograms to obtain S1 and S2 peaks compatible with standard Rock-Eval pyrolysis. An automated cryotrapping method allows the sequential sampling of product from defined pyrolysis portions. Each subsample is subsequently transferred to the isotopic ratio mass spectrometer for carbon isotopic measurements. In addition, the cryotrap serves to focus sample peaks, enabling robust and reproducible results even at standard Rock-Eval heating rates. In combination with a standard elemental analyser coupled to an isotopic ratio mass spectrometer (EA–IRMS) it was possible to deconvolute the carbon isotope composition of the reactive components, bitumen and inert components of OM. This allowed us to observe depositional control as well as changes imposed by maturation. Our initial results show the potential of the proposed isotopic screening method to deduce a variety of organic geochemical properties of different OM types based on differences in their carbon isotope compositions. Our results suggest that the ability to produce significant isotopic fractionation during the proposed pyrolysis method is highly dependent on the preservation state of the OM and the thermal maturity.

Essential oils: the review of the methods for determining the authenticity and detecting adulteration

Essential oils are the products of natural origin that find a wide variety of applications in various industries. The high cost, laboriousness of production and widespread use lead to the fact that they are often found falsified. The use of fake oils increases their danger to humans, and therefore the establishment of the authenticity of essential oils is of a great importance. In this review, the authors analyze the published works and normative documents on the issues of determining the authenticity and identification of falsification of the essential oils. The component composition of essential oils, its variability depending on the place of growth of the essential oil plant and the technology of oil separation are considered. The main methods of falsification of essential oils and the range of techniques used for the control of the authenticity of products are discussed. The authors analyze the literature and the regulatory framework governing the quality of essential oils, existing methods for determining their authenticity, and indicate the respective advantages and disadvantages. A particular attention is paid to the method of mass spectrometry of isotope ratios, as the most promising, due to the high accuracy and the possibility of using practically any type of oil for the research. The authors confirm the widespread use of the isotope ratio mass spectrometry method in practice with the specific examples and demonstrate the new capabilities of this method associated with the use of isotope profiling and combined isotope analysis methods, which is an indicator for any artificial processes that occur with essential oils as a result of falsification. Keywords: essential oils, component composition, falsification, authenticity, methods, chromatography, spectroscopy, isotope ratio mass spectrometry DOI: http://dx.doi.org/10.15826/analitika.2019.23.4.010 (Russian) I.V. Lapko 1 , Yu.U. B. Aksenova 1 , *O.V. Kuznecova 2 , S.V. Vasilevskij 1 , A.V. Aksenov 1 , V.F. Taranchenko 1 , A.M. Antohin 1 , A.A. Ihalajnen 1 1 Scientific Center «Signal», Bolshaya Olenya Street, 8, Moscow, 107014, Russsian Federation 2 Vernadsky Institute of Geochemistry and Analytical Chemistry of Russian Academу of Sciences, Kosygina str., 19, Moscow, 119991, Russsian Federation

Compound-Specific Carbon Isotopic Composition of Ethanol in Brazil and US Vehicle Emissions and Wet Deposition.

Global atmospheric ethanol budget models include large uncertainties in the magnitude of ethanol emission sources and sinks. To apply stable isotope techniques to constrain ethanol emission sources, a headspace solid phase microextraction gas chromatograph-combustion-isotope ratio mass spectrometry method (HS-SPME-GC-C-IRMS) was developed to measure the carbon isotopic composition of aqueous phase ethanol at natural abundance levels (1-30 μM) with a precision of 0.4‰. The method was applied to determine the carbon isotope signatures (δ13C) of vehicle ethanol emission sources in Brazil (-12.8 ± 2.4‰) and the US (-9.8 ± 2.5‰), and to measure the carbon isotope composition of ethanol in wet deposition (-22.6 to -12.7‰). A two end-member isotope mixing model was developed using anthropogenic and biogenic end members and fractionation scenarios to estimate ethanol source contributions to wet deposition collected in Brazil and US. Mixing model results indicate anthropogenic sources contribute two and a half to four times more ethanol to the atmosphere than previously predicted in modeled global ethanol inventories. As established and developing countries continue to rapidly increase ethanol fuel consumption and subsequent emissions, understanding the magnitude of all ethanol sources and sinks will be essential for modeling future atmospheric chemistry and air quality impacts.

Online wet oxidation/isotope ratio mass spectrometry method for determination of stable carbon isotope ratios of water-soluble organic carbon in particulate matter.

Water-soluble organic carbon (WSOC) is formed by oxidation of organic compounds in particulate matter (PM) and accounts for 25-80% of the organic carbon in PM. Stable carbon isotope ratio (δ13 C) analysis is widely used to identify the sources of PM, but determining the δ13 C values of WSOC is complicated and requires a time-consuming pretreatment process. We have developed an online wet oxidation/isotope ratio mass spectrometry method with a reduced pretreatment time. We have measured the δ13 C values of WSOC by using this method. The method showed high accuracy (0.1‰) and precision (0.1‰) for levoglucosan, and the limit of detection was sufficiently low for WSOC analysis. Using this method, we determined δ13 C values of WSOC in PM2.5 samples collected in Japan during the period from July to November 2017 and found that the values ranged from -26.5‰ to -25.0‰ (average, -25.8‰). Our simple, low-blank method could be used for rapid quantitative analysis of the δ13 C values of WSOC in PM2.5 . We propose that this online method be used as a standard method for δ13 C analysis of WSOC.

Laboratory-based hyperspectral image analysis for predicting soil carbon, nitrogen and their isotopic compositions

The common methods of determining soil carbon (C), nitrogen (N) and their isotopic compositions (δ13C and δ15N) are expensive and time-consuming. Therefore, alternative low-cost and rapid methods are sought to address this issue. This study aimed to investigate the potential of hyperspectral image analysis to predict soil total carbon (TC), total nitrogen (TN), δ13C and δ15N. Hyperspectral images were captured from 96 ground soil samples using a laboratory-based visible to near-infrared (VNIR) hyperspectral camera in the spectral range of 400–1000 nm. Partial least squares regression (PLSR) models were developed to correlate the values of TC, TN, δ13C and δ15N, obtained from isotope ratio mass spectrometry method, with their spectral reflectance. The developed models provided acceptable predictions with high coefficient of determination (R2c) and low root mean square error (RMSEc) of calibration set for TC (R2c = 0.82; RMSEc = 1.08%), TN (R2c = 0.87; RMSEc = 0.02%), δ13C (R2c = 0.82; RMSEc = 0.27‰) and δ15N (R2c = 0.90; RMSEc = 0.29‰). The prediction abilities of the models were then evaluated using the spectra of an external test set (24 samples). The models provided excellent predictions with high R2t and ratio of performance to deviation (RPD) of test set for TC (R2t = 0.76; RPD = 2.02), TN (R2t = 0.86; RPD = 2.08), δ13C (R2t = 0.80; RPD = 2.00) and δ15N (R2t = 0.81; RPD = 1.94). The results indicated that the laboratory-based hyperspectral image analysis has the potential to predict soil TC, TN, δ13C and δ15N.

Development and validation of a multidimensional gas chromatography/combustion/isotope ratio mass spectrometry-based test method for analyzing urinary steroids in doping controls

The misuse of the steroid hormone testosterone for performance enhancement has been frequently reported in the past, and its administration is prohibited in sports according to the regulations of the World Anti-Doping Agency (WADA). Testosterone is produced endogenously in human. Endogenous and exogenous testosterone together with their metabolites can be unambiguously distinguished by means of their carbon isotope ratios if compared to endogenous reference compounds. Established isotope ratio mass spectrometry methods for analyzing urinary steroids for doping control purposes consist of up to two time-consuming HPLC purification steps to achieve the required purity of all analytes. In order to accelerate the sample preparation, multidimensional gas chromatography was applied. This technique is known to be suitable for the separation of complex matrices. Multidimensional gas chromatography consists of two gas chromatographs connected by a pressure-controlled heart-cutting device. In the first dimension, a less polar capillary column was installed for peak purification. In the second dimension, separation was achieved employing a column of medium polarity. Retention time stability and transfer windows were monitored by a flame ionization detector. Detection was performed simultaneously by isotope ratio mass spectrometry and a single quadrupole mass spectrometer for analyte identity confirmation and assessment of peak purity.Instead of two working days required for the HPLC-based routine method, the sample preparation is shortened by the herein presented approach to one working day. For glucuronic acid-conjugated steroids, sample pretreatment is based on solid-phase extraction, liquid-liquid extraction, enzymatic hydrolysis, and derivatization of the target analytes to their corresponding acetates. These steroid acetates are divided according to their polarity into two fractions by solid phase extraction. Further, sulfoconjugated steroids are processed by Pseudomonas aeruginosa arylsulfatase and extracted following a recently established procedure.Following WADA guidelines, the method was validated by determining the parameters linear range, limit of quantification, intra- and interday precision, accuracy and specificity utilizing linear mixing models. Additionally, a reference population (n = 74) was investigated and the obtained data were compared to the established method. An excretion study was also conducted with 4-androstenedione to prove the fit for purpose of the methodology. The results demonstrate that the method is suitable for an application in routine doping control analysis.

Potential for natural and enhanced attenuation of sulphanilamide in a contaminated chalk aquifer

Understanding antibiotic biodegradation is important to the appreciation of their fate and removal from the environment. In this research an Isotope Ratio Mass Spectrometry (IRMS) method was developed to evaluate the extent of biodegradation of the antibiotic, sulphanilamide, in contaminated groundwater. Results indicted an enrichment in δ13C of 8.44‰ from −26.56 (at the contaminant source) to −18.12‰ (300m downfield of the source). These results confirm reductions in sulphanilamide concentrations (from 650 to 10mg/L) across the contaminant plume to be attributable to biodegradation (56%) vs. other natural attenuation processes, such as dilution or dispersion (42%). To understand the controls on sulphanilamide degradation ex-situ microcosms assessed the influence of sulphanilamide concentration, redox conditions and an alternative carbon source. Results indicated, high levels of anaerobic capacity (~50% mineralisation) to degrade sulphanilamide under high (263mg/L), moderate (10mg/L) and low (0.02mg/L) substrate concentrations. The addition of electron acceptors; nitrate and sulphate, did not significantly enhance the capacity of the groundwater to anaerobically biodegrade sulphanilamide. Interestingly, where alternative carbon sources were present, the addition of nitrate and sulphate inhibited sulphanilamide biodegradation. These results suggest, under in-situ conditions, when a preferential carbon source was available for biodegradation, sulphanilamide could be acting as a nitrogen and/or sulphur source. These findings are important as they highlight sulphanilamide being used as a carbon and a putative nitrogen and sulphur source, under prevailing iron reducing conditions.

Technical note: Coupling infrared gas analysis and cavity ring down spectroscopy for autonomous, high-temporal-resolution measurements of DIC and &amp;lt;i&amp;gt;δ&amp;lt;/i&amp;gt;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C–DIC

Abstract. A new approach to autonomously determine concentrations of dissolved inorganic carbon (DIC) and its carbon stable isotope ratio (δ13C–DIC) at high temporal resolution is presented. The simple method requires no customised design. Instead it uses two commercially available instruments currently used in aquatic carbon research. An inorganic carbon analyser utilising non-dispersive infrared detection (NDIR) is coupled to a Cavity Ring-down Spectrometer (CRDS) to determine DIC and δ13C–DIC based on the liberated CO2 from acidified aliquots of water. Using a small sample volume of 2 mL, the precision and accuracy of the new method was comparable to standard isotope ratio mass spectrometry (IRMS) methods. The system achieved a sampling resolution of 16 min, with a DIC precision of ±1.5 to 2 µmol kg−1 and δ13C–DIC precision of ±0.14 ‰ for concentrations spanning 1000 to 3600 µmol kg−1. Accuracy of 0.1 ± 0.06 ‰ for δ13C–DIC based on DIC concentrations ranging from 2000 to 2230 µmol kg−1 was achieved during a laboratory-based algal bloom experiment. The high precision data that can be autonomously obtained by the system should enable complex carbonate system questions to be explored in aquatic sciences using high-temporal-resolution observations.

An extractive removal step optimized for a high-throughput α-cellulose extraction method for δ13C and δ18O stable isotope ratio analysis in conifer tree rings.

Stable isotope ratios (δ13C and δ18O) of tree-ring α-cellulose are important tools in paleoclimatology, ecology, plant physiology and genetics. The Multiple Sample Isolation System for Solids (MSISS) was a major advance in the tree-ring α-cellulose extraction methods, offering greater throughput and reduced labor input compared to traditional alternatives. However, the usability of the method for resinous conifer species may be limited by the need to remove extractives from some conifer species in a separate pretreatment step. Here we test the necessity of pretreatment for α-cellulose extraction in loblolly pine (Pinus taeda L.), and the efficiency of a modified acetone-based ambient-temperature step for the removal of extractives (i) in loblolly pine from five geographic locations representing its natural range in the southeastern USA, and (ii) on five other common coniferous species (black spruce (Picea mariana Mill.), Fraser fir (Abies fraseri (Pursh) Poir.), Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), Norway spruce (Picea abies (L.) Karst) and ponderosa pine (Pinus ponderosa D.)) with contrasting extractive profiles. The differences of δ13C values between the new and traditional pretreatment methods were within the precision of the isotope ratio mass spectrometry method used (±0.2‰), and the differences between δ18O values were not statistically significant. Although some unanticipated results were observed in Fraser fir, the new ambient-temperature technique was deemed as effective as the more labor-consuming and toxic traditional pretreatment protocol. The proposed technique requires a separate acetone-inert multiport system similar to MSISS, and the execution of both pretreatment and main extraction steps allows for simultaneous treatment of up to several hundred microsamples from resinous softwood, while the need of additional labor input remains minimal.

Notes on the origin of copromacrinite based on nitrogen functionalities and δ13C and δ15N determined on samples from the Peach Orchard coal bed, southern Magoffin County, Kentucky

This paper represents the first attempt to show, by means other than just petrographic ones, that one type of macrinite, herein designated copromacrinite, may result from macrofauna feces. For that purpose a combination of coal petrography, X-ray photoelectron spectroscopy, and elemental-analysis continuous-flow isotope ratio mass spectrometry methods were used to determine nitrogen functionalities and δ13C and δ15N compositions in 1) vitrinite-rich, 2) fusinite+semifusinite-rich, and 3) macrinite-rich (with a possible coprolitic origin) samples of the high volatile A bituminous Peach Orchard coal (Bolsovian; Middle Pennsylvanian) from Magoffin County, Kentucky. There were no significant differences between pyridinic-N and quaternary-N abundance in the three samples, however, pyrrolic-N was higher (~54%) in the macrinite-rich sample than in the other two samples (~38%). The data suggest that pyridinic-N and quaternary-N are independent of maceral group composition and that pyrrolic-N is dependent on maceral composition (fusinite+semifusinite versus macrinite). δ13C values obtained for bulk and demineralized coal of the vitrinite- and fusinite+semifusinite-rich samples are similar with δ13C values of −24.80±0.01‰ VPDB and −24.61±0.09‰ VPDB for bulk samples and −24.81±0.07‰ VPDB and −24.52±0.04‰ VPDB for demineralized samples. These values are within the expected range for vitrinite-rich samples and the slightly higher δ13C value of the fusinite+semifusinite-rich sample is expected as δ13C values for inertinite are higher than for vitrinite. However, there was a significant shift to a lower δ13C value (−26.80±0.01‰ VPDB for the bulk sample value) for the macrinite-rich sample. Because the samples are basically isorank, and δ13C (and δ15N) shifts do not occur during maturation until anthracite rank, the difference may be related to the presence or composition of the macrinite within the sample which lacks heat-effect indicators, such as devolatilization vacuoles and distorted pores. δ15N values are also similar for bulk and demineralized coal of the vitrinite- and fusinite+semifusinite-rich samples, and the bulk values were heavier in this samples (3.07±0.03‰ Air and 2.92±0.10‰ Air, respectively), and much lighter (−2.83±0.09‰ Air) for the macrinite-rich sample.The study of Peach Orchard coal samples using reflected-light microscopy, isotopic composition, and nitrogen-forms analyses revealed that the macrinite-rich sample contains macrinite with coprolitic features (e.g. oxidation rind, mix of undigested palynomorphs, frequent and randomly located funginite, agglutination pulp of semifusinite reflectance, internal lack of bedding fabric, and suggestion of structures resulting from intestines and stomach walls), more pyrrolic-N (~16%), and lower δ13C (~2‰ VPDB) and δ15N (~4‰ Air) values than the vitrinite and semifusinite+fusinite rich samples. These findings suggest that the maceral macrinite has multiple origins based on petrography and measurable chemical differences between the macrinite, vitrinite, and semifusinite+fusinite fractions within the coal. Assuming that copromacrinite observed is an excretion then the anomalies observed may result from the symbiotic relations between the macrofauna (e.g. cockroaches) and microbiota during the digestive processes, and the nitrogen balance mechanisms inside macrofauna body.