Mass Spectrometer System Research Articles

Determining the taxol contents of yew tree populations in western Black Sea and Marmara regions and analyzing some forest stand characteristics

Yew tree (Taxus baccata L.) is mainly populated in Türkiye, Europe, and Caucasia regions. It has natural anticancer compounds and is a source of raw materials used in modern medicine. The present study aimed to examine the taxol contents of yew trees naturally grown in Marmara and Western Black Sea regions by subjecting needle samples taken from 17 yew populations to extraction and liquid chromatography tandem mass / mass spectrometer system (LC-MS/MS) analysis. It was also examined whether a relationship exists between some stand characteristics and taxoid contents of the needles. From these analyses, the highest taxol contents were found in Bartın-Gölderesi, Yığılca-Kurtkayası, İnebolu-Karagöl, and Yenice-Kızılkaya populations. The statistical analyses showed that there were significant relationships between compound contents and slope, humus content, total nitrogen content (%), and potassium (K). It is recommended to use these derivatives obtained from natural forests in sapling nursing and tissue culture studies, to produce pharmaceutical materials from leaves and protect and improve the current gene sources.

Magnetic field effects on characteristics of counterflow diffusion ethylene flame: An experimental study

The present study was aiming to obtain the effects of magnetic gradients with varying direction on counterflow diffusion ethylene flames, including the flame shape, chemical structure and soot concentration distribution. Experiments were performed using flame imaging with a digital camera, two-color pyrometry, and flame speciation with gas chromatography (GC)/mass spectrometer (MS) system. When upward and horizontal outward magnetic gradients were introduced to flames, it was discovered that the mean flame temperature rose and the mean soot concentration dropped in the sooting region, while an opposite trend was observed with the addition of downward magnetic gradient. Meanwhile, results revealed that the presence of the upward or horizontal outward magnetic gradients could accelerate the consumption of ethylene and encourage the conversion of intermediate hydrocarbon species to CO and CO2 in the flame area, while the oxidation of fuel and intermediate hydrocarbon species were inhibited and the formation of the aromatics was promoted with the application of the downward magnetic gradient. Furthermore, it was noted that the changing trend of aromatics was consistent with that of soot. The reason might be understood from the variation of magnetic force imposed on oxygen, which in turn affected the fuel consumption and soot distribution.

Correlative high-resolution imaging of hydrogen in Mg2Ni hydrogen storage thin films

Nanometer scale imaging of hydrogen in solid materials remains an important challenge for the characterization of advanced materials, such as semiconductors, high-strength metallic alloys, and hydrogen storage materials. Within this work, we demonstrate high-resolution imaging of hydrogen and deuterium within Mg2Ni/Mg2NiH4 hydrogen storage thin films using an in-house developed secondary ion mass spectrometer (SIMS) system attached to a commercially available dual-beam focused ion beam - scanning electron microscope (FIB-SEM) instrument. We further demonstrate a novel approach to measure the size, shape, and distribution of the hydride phase in partially transformed films using laser scanning confocal microscopy (LSCM) to measure surface topography changes from the hydride phase volume expansion. Combining these techniques provides new insights on hydride nucleation and growth within the Mg2NiHx system. Finally, we demonstrate the efficacy of tracking deuterium as a hydrogen analog to reduce the background for SIMS imaging of hydrogen in high-vacuum chambers (∼10−6 mbar).

Dissociative photoionization ofm-xylene

The photoionization and dissociative photoionization of m-xylene (C8H10) were researched by using synchrotron radiation vacuum ultraviolet (SR-VUV) and supersonic expanding molecular beam reflectron time-of-flight mass spectrometer (RFTOF-MS) system. The photoionization efficiency spectra (PIEs) of parent ion C8H10+ and main fragment ions C8H9+ and C7H7+ were observed, and the ionization energy (IE) of m-xylene and appearance energies (AEs) of main fragment ions C8H9+ and C7H7+ were determined to be 8.60±0.03 eV, 11.76±0.04 eV and 11.85±0.05 eV, respectively. Structures of reactant, transition states (TSs), intermediates (INTs), and products involved in two dominant dissociation channels were optimized at the B3LYP/6-311++G(d,p) level, and the relative energies were calculated at the G3 level. Based on the results, two major dissociative photoionization channels, C7H7++CH3 and C8H9++H were calculated at the B3LYP/6-311++G(d,p) level. On the basis of theoretical and experimental results, the dissociative photoionization mechanisms of m-xylene were proposed. The C–H or C–C bond dissociation and hydrogen migration are the main processes in the dissociation channels of m-xylene cation.

In-Tube Solid-Phase Microextraction Directly Coupled to Mass Spectrometric Systems: A Review

Since it was introduced in 1997, in-tube solid-phase microextraction (in-tube SPME), which uses a capillary column as extraction device, has been continuously developed as online microextraction coupled to LC systems (in-tube SPME-LC). In the last decade, new couplings have been evaluated on the basis of state-of-the-art LC instruments, including direct coupling of in-tube SPME to MS/MS systems, without chromatographic separation, for high-throughput analysis. In-tube SPME coupling to MS/MS has been possible thanks to the selectivity of capillary column coatings and MS/MS systems (SRM mode). Different types of capillary columns (wall-coated open-tubular, porous-layer open-tubular, sorbent-packed, porous monolithic rods, or fiber-packed) with selective stationary phases have been developed to increase the sorption capacity and selectivity of in-tube SPME. This review focuses on the in-tube SPME principle, extraction configurations, current advances in direct coupling to MS/MS systems, experimental parameters, coatings, and applications in different areas (food, biological, clinical, and environmental areas) over the last years.

Evaluation and improvement of a miniature mass spectrometry system for quantitative harm reduction drug checking

The increasing variability of the illicit drug market has imposed serious health risks for people who use drugs (PWUD), particularly due to the increasing co-occurrence of opioids and etizolam (or other benzodiazepines) in some jurisdictions. A miniature mass spectrometer (MS) equipped with paper capillary spray ionization was evaluated for its ability to quantify fentanyl, fluorofentanyl, carfentanil, and etizolam in illicit drug samples. Prior to testing actual drug samples, inter- and intra-day reproducibility, calibration linearity, and analytical sensitivity were assessed. The development of a continuous spray solvent delivery system improved MS/MS quantitation by prolonging ionization stability. A simple, rapid and quantitative tandem mass spectrometry method was developed and employed for the analysis of real-world illicit drug samples provided by PWUD at a harm reduction site in Victoria, British Columbia, Canada. Limits of detection ranged from 0.001 to 0.24% w/w of illicit analyte in the original solid drug samples. Target analytes were detected and quantified via the miniature MS system for samples where conventional on-site drug checking technologies were not always effective. These promising results demonstrate the potential role for miniature mass spectrometer systems for on-site drug checking services that can be both sensitive to trace, toxic levels as well as adaptable/selective for new drug threats as they appear in the illicit drug supply.

An experimental and modeling study of tetramethyl ethylene pyrolysis with polycyclic aromatic hydrocarbon formation

Iso-olefins, in the C5–C8 range can potentially be blended with renewable gasoline fuels to increase their research octane number (RON) and octane sensitivity (S). RON and S increase with the degree of branching in iso-olefins and this is a desirable fuel anti-knock quality in modern spark-ignited direct-injection engines. However, these iso-olefins tend to form larger concentrations of aromatic species leading to the formation of polycyclic aromatic hydrocarbons (PAHs). Thus, it is important to understand the pyrolysis chemistry of these iso-olefins. In this study, a new detailed chemical kinetic mechanism is developed to describe the pyrolysis of tetramethyl ethylene (TME), a symmetric iso-olefin. The mechanism, which includes the formation of PAHs, is validated against species versus temperature (700–1160 K) measurements in a jet-stirred reactor at atmospheric pressure and in a single-pulse shock tube at a pressure of 5 bar in the temperature range 1150–1600 K. Synchrotron vacuum ultraviolet photoionization mass spectrometer (SVUV-PIMS) and gas chromatography (GC) systems were used to quantify the species in the jet-stirred reactor and in the single-pulse shock tube, respectively. The mechanism derives its base and PAH chemistry from the LLNL PAH sub-mechanism. The predictions are accurate for most of the species measured in both facilities. However, there is scope for mechanism improvement by understanding the consumption pathways for some of the intermediate species such as isoprene. The formation of 1, 2, and 3-ring aromatic species such as benzene, toluene, naphthalene and phenanthrene measured experimentally is analyzed using the chemical kinetic mechanism. It is found that the PAH formation chemistry for TME under pyrolysis conditions is driven by both propargyl addition reactions and the HACA mechanism.

A robust LC-MS/MS method to measure 8-oxoGuo, 8-oxodG, and NMN in human serum and urine

ObjectiveTo establish and validate a robust LC-MS/MS method for simultaneously measuring 8-oxoGuo, 8-oxodG, and NMN in serum and urine to evaluate the oxidative stress status. MethodsA Waters TQ-XS triple quadrupole mass spectrometer system coupled with an Acquity UPLC Primer HSS T3 column was chosen. The clinical performance was verified according to the CLSI C62-A and EP-15 guidelines. Furthermore, matched serum and urine samples from 22 apparently healthy check-ups, 20 patients with atherosclerosis, and 18 individuals with dementia were evaluated. ResultsThe recovery for serum 8-oxoGuo, urine 8-oxoGuo, serum 8-oxodG, urine 8-oxodG, serum NMN, and urine NMN was 88.8–112.4%, 102.4–114.1%, 88.5–107.7%, 94.9–102.6%, 98.4–108.9%, and 88.5–108.6%, respectively. Based on the inter-assay results, total coefficient of variation, matrix effect, and carryover, the LC-MS/MS method was deemed robust. The limit of quantification was 0.017, 0.018, and 0.150 nmol/L for 8-oxoGuo, 8-oxodG, and NMN, respectively, which are suitable for accurate measurements in human serum and urine samples. Higher 8-oxoGuo and 8-oxodG levels and lower NMN levels, indicative of significantly higher oxidative stress status, were found in patients with dementia compared to healthy subjects. ConclusionWe established and validated a robust LC-MS/MS method to simultaneously measure 8-oxoGuo, 8-oxodG, and NMN in serum and urine.

Active Pharmaceutical Ingredients Sequestrated from Water Using Novel Mesoporous Activated Carbon Optimally Prepared from Cassava Peels

The increasing occurrence of active pharmaceutical ingredients (APIs) in water systems coupled with their recalcitrance to conventional water treatment methods calls for research into more eco-friendly and cost-effective curbing media. Mesoporous cassava peel activated carbon (CPAC) was prepared under conditions derived from optimizing the surface area and yield with the temperature and holding time as the model inputs using the response surface methodology. The sequestration potential and mechanisms of the resultant activated carbon (AC) for active pharmaceutical ingredients from wastewater were studied using batch experiments. The CPAC adsorption kinetics and isothermal mechanisms for the three pharmaceuticals (carbamazepine (CBZ), clarithromycin (CLN), and trimethoprim (TRM)) were studied in both wastewater and Milli-Q water. The API concentrations were measured using liquid chromatography coupled to a mass spectrometer (LC-MS) system. The maximum removal efficiencies were 86.00, 58.00, and 68.50% for CBZ, CLN, and TRM for wastewater, which were less than those from the Milli-Q water at 94.25, 73.50, and 84.5%, respectively. The sorption process for the CLN was better explained by the Freundlich model, whereas the CBZ and TRM adsorption processes could suitably be explained by both the Langmuir and Freundlich models. At an initial concentration of 20 mgL−1 for all APIs and a CPAC dosage of 2.0 gL−1, the maximum adsorption capacities were 25.907, 84.034, and 1.487 mgg−1 for CBZ, TRM, and CLN, respectively. These results demonstrated the potential of CPAC to remove APIs from water, with its sequestration potential being more exhibited after the removal of the organic matter owing to the lower competition for active sites by the APIs. Additionally, positive adsorbates were better removed than negatively charged adsorbates due to the dominance of anions in the cassava peel lattice.

Sr ISOTOPES BY LA-MC-ICP-MS PROCEDURES COUPLED WITH THE MACS3 REFERENCE MATERIAL IN A CORAL SAMPLE: A RECORD OF ENVIRONMENTAL CHANGES

The main aim of this work is to demonstrate that the Laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) is a powerful tool for the analysis of strontium (Sr) isotopes in corals. This work discusses certification strategies for Sr isotopes determination, using reference material (RM) analyses and the results treatment based on detailed data acquired in biological materials, a coral sample. To obtain reliable results, it is essential to properly adjust the mass spectrometer and laser ablation system. Adjusting the equipment to its maximum intensity does not always result in correct 87Sr/86Sr ratios. Therefore, the optimization of the mass spectrometer was performed using the reference material NIST SRM-987 (solution) and adjusting the correct Sr isotope ratio to the reference material (USGS MACS3 and NIST-612, solids) before each analytical session. The protocol applied the solid reference material USGS MACS3 with an isotopic ratio 87Sr/86Sr of 0.72000. The values obtained for this RM varied between 0.7012 and 0.7014, with a correction factor calculated between 0.990 and 0.988. In order to account for potential drifts in the mass spectrometer during an analytical session, the application of bracketing correction and the use of the most convenient reference material are suggested. The analytical uncertainty of Sr data obtained by LA-MC-ICP-MS is comparable to studies carried out on other carbonate materials. The results of ablation techniques are reproducible within the analytical error, which implies that this technique produces robust results when applied to coral carbonates. In addition, several comparative measurements of different reference materials (e.g. USGS MACS3 and NIST 612) and the comparison of the 87Sr/86Sr ratios highlight the robustness of the method. The results along the coral growth axes showed a decrease in the 87Sr/86Sr ratio from the inner to the outer layer of the coral (from 0.70920 to 0.70627), which indicate variations in the availability of particulate matter during the coral growth, probably related to local marine environmental changes.

Rapid separation and identification of 96 main constituents in Huanglian Jiedu decoction via ultra-high performance liquid chromatography-Orbitrap Fusion Tribrid mass spectrometer.

Huanglian Jiedu decoction is a widely used traditional Chinese medicine with a broad spectrum of therapeutic effects, including heat clearing, detoxification, and attenuation of inflammation. However, the composition of Huanglian Jiedu decoction is still unclear due to its complexity and limitations of analytical methods. In this study, we established a fast and reliable analytical method based on ultra-performance LC-Orbitrap Fusion Tribrid mass spectrometer for high-speed separation and structural identification of multiple compounds in Huanglian Jiedu decoction. The analysis was carried out using a Hypersil GOLD C18 column (2.1 × 100 mm, 1.9μm) with gradient elution coupled to a high-definition mass spectrometer system operating in both positive and negative ESI modes. According to the chromatographic retention time, precise molecular weight, fragment ion peaks, and published data, the main chromatographic peaks were attributed to specific molecules whose chemical structures were determined. In total, 96 components were identified, including 34 flavonoids and their glycosides, 23 alkaloids, 18 organic acids, 13 terpenoids, and 8 miscellaneous compounds. This study revealed the detailed chemical composition of Huanglian Jiedu decoction, which is of great importance for quality control and further pharmacological and mechanistic studies.

Statistical assessment of long-term performance for AMS measurements at IUAC, New Delhi

A 500 kV ion Accelerator based Accelerator Mass Spectrometer (AMS) system was established in 2015 at the Inter-University Accelerator Centre (IUAC), New Delhi, India (14C Lab Code: IUACD) and is being used routinely for 14C, 10Be and 26Al measurements. The AMS System is backed by three automated graphitization equipment (AGE), a carbonate handling system (CHS) in graphitization laboratory and an appropriate clean laboratory for the chemical processing of samples in case of 10Be and 26Al measurements. In view of the increasing demand for 14C based studies, a major portion of the machine time goes into 14C measurements as compared to other isotopes.It is imperative to assess, monitor and establish the consistency of the performance of the AMS measurements over time since its inception. We have evaluated the short- and long-term performance of 14C measurements with the AMS set-up at IUAC, New Delhi, in terms of the reproducibility, accuracy, precision and calculation of random machine error (RME) in a routine laboratory environment using the International Atomic Energy Agency (IAEA) secondary standards (C1-C9) and chemical blanks in each session. A comparison of the analytical figures of merit between the short- & long-term usages of the AMS facility is presented through a statistical approach highlighting the importance of the measurements and evaluation of primary standards, secondary standards, blanks, and replicates in each of the experiments. A comparison of the analytical performances between the initial set-up and later adoption of a modified analytical protocol has also been made.

Phytochemical characterization and assessments of antimicrobial, cytotoxic and anti-inflammatory properties of Lavandula coronopifolia Poir. volatile oil from Palestine

Since the dawn of time, people have relied on herbal medicine to heal many ailments. Lavandula coronopifolia (LC) is an aromatic plant that has been utilized in ethnomedicine since ancient times. This investigation aimed to figure out the chemical constituents of the volatile oil (VO) of the LC herb from Palestine for the first time and determine its microbicidal, anti-inflammatory, and cytotoxic effects. The LC aerial parts VO phytochemical constituent characterizations were performed utilizing gas chromatography linked to a mass spectrometric system. While, the effects of LC-VO's ability to suppress microbial growth were established against selected bacterial and fungal strains by a broth microdilution technique. Besides, an in vitro cyclooxygenase enzyme (COX) suppressant bioassay kit was utilized to estimate the anti-inflammatory effect against bovine cyclooxygenase (COX) type 1 and 2. In addition, the colorimetric MTS test was employed to determine the cytotoxic activity against the cervical adenocarcinoma (HeLa) tumor cell line. Linalyl acetate (41.65 ± 0.91%) and linalool (41.41 ± 0.77%) were identified as major components of LC-VO, and oxygenated monoterpenoid was the dominant phytochemical class of this VO. The LC-VO demonstrated potent bactericidal and fungicidal effects, especially on methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Proteus vulgaris, and Candida albicans (MIC = 0.33 ± 0.03, 0.63 ± 0.1, 1.25 ± 0.81, and 0.16 ± 0.06 µg/mL), respectively. Besides, LC-VO suppressed COX enzymes type-1 and −2, with an inhibition percentage at 50 µg/mL of 95.00 and 88.02 percent, respectively, in comparison with the positive control, ketoprofen non-steroidal anti-inflammatory drugs (NSAID), at the same concentration with an inhibition percentage of 96.25 and 65.02%, respectively. In addition, the LC-VO inhibited the growth of HeLa cells dose-dependently, with an IC 50 dose of 0.71 ± 0.01 µg/mL. The current study demonstrates that LC-VO is a promising alternative for the healing or preventing various infectious diseases, cancer, and chronic inflammation. These results reveal that LC-VO has beneficial health benefits and has the potential to be utilized for therapeutic purposes.

Grelin ve Grelin Reseptörü Polimorfizmlerinin Tip 2 Diyabetle İlişkisi

Bir gastrik peptit olan grelin ve onun büyüme hormonu salgılatıcı G protein-bağlı reseptörünün glukoz metabolizması ve enerji homeostazında önemli bir rol oynadığına dair ciddi kanıtlar mevcuttur. Bu nedenle, Tip 2 diyabet için duyarlılık alelleri taşıyan bu genler potansiyel birer aday olarak değerlendirilmektedir. Isparta yöresinden 75 Tip 2 diyabet hastası ve 25 kontrolden oluşan 100 Türk yetişkin bireyin dahil edildiği vaka-kontrol kesitsel ilişkilendirme çalışması yapıldı. Grelin geninde dört promotör (rs26311, rs26312, rs27647, rs3755777) ve bir intronik (rs35683) bölge ve Grelin reseptöründe bir intronik (rs509035) ve bir 3'UTR (rs565105) bölge tek nükleotid polimorfizmleri seçilerek Tip 2 diyabet ile ilişkisi Matris Destekli Lazer Desorpsiyon/İyonizasyon Uçuş Süresi Kütle Spektrometresi sistemi kullanılarak araştırıldı. Tip 2 diyabet ile iki adet tek nükleotid polimorfizmi arasında anlamlı bir ilişki saptandı: Grelin geninin promotör bölgesinde yer alan rs27647 ve intron 1'de bulunan rs35683 (P<0.05). Sonuç olarak, elde edilen bulgular Isparta yöresinde yaşayan Tip 2 diyabet toplumunda grelin polimorfizmlerinin hastalık gelişimine yatkınlık oluşturabileceğini düşündürmektedir.

SAMHSA drug panel screening in oral fluid: Development of screening method at 8 seconds per sample using LDTD-MS/MS

In 2019, the US Department of Health and Human Services (via the SAMHSA agency) has established scientific and technical guidelines for federal workplace drug testing programs in oral fluids (Federal Register/Vol. 84, No. 207, 2019). Screening various drug classes requires several different immunoassay reagents or an LC-MS/MS method with a longer analysis time per sample. LDTD-MS/MS technology combines the speed and the analysis of different drug classes with a single method. The goal of this presentation is to use an automated sample preparation method for LDTD-MS/MS screening of all compounds in a single operation. Quantisal collection devices were used in this method. Drug-free oral fluids of different volunteers were collected using the Quantisal device. After the collection of the oral fluid, the pad is transferred into a tube containing an extraction buffer. During this process, oral fluids are diluted by a factor of 3. The SAMHSA drug panel for an Oral fluid screen was spiked in extracts at a concentration around the decision point cut-off (Amphetamine: 50 ng/mL, Methamphetamine: 50 ng/mL, MDA: 50 ng/mL, MDMA: 50 ng/mL, PCP: 100 ng/mL, Morphine: 30 ng/mL, Hydromorphone: 30 ng/mL, Codeine: 30 ng/mL, Hydrocodone: 30 ng/mL, Cocaine: 30 ng/mL, Oxymorphone: 30 ng/mL, Oxycodone: 30 ng/mL, 6-AM: 4 ng/mL and THC: 4 ng/mL). Samples were extracted using the Azeo automated extraction system. The robot scans the barcode of the sample, generates a batch file for the LDTD-MS/MS system, extracts the sample and spots the LazWell plate. Salt assisted liquid-liquid extraction (SALLE) was used as the sample preparation method. LDTD (Phytronix Luxon) uses a carrier gas (air) flow rate of 6 L/min with water infusion at 20 uL/sec. Samples were desorbed from the surface of the plate using a laser ramp of 6 seconds to 65% power and 2 seconds hold at 65% power. Mass spectrometer (Shimadzu 8060) operates in positive MRM mode with a specific transition for the following drugs: Amphetamine, Methamphetamine, MDA, MDMA, PCP, Morphine, Hydromorphone, Codeine, Hydrocodone, Cocaine, Oxymorphone, Oxycodone, 6-AM and THC. Data acquisition systems of mass spectrometers were not designed to deal with signals of only a few seconds per sample. The synchronization sequence adds 6 to more than 15 seconds between each sample. To bypass this, all samples are acquired in a single file. To allow the analysis of such data, Cascade™ software is designed to detect, split, and integrate every sample peak acquired in a single file. Spiked samples around the decision point and blank solutions are used to validate the precision of the method. Each concentration must not exceed 20% CV and the mean concentration ± 2 times the standard deviation must not overlap with other concentrations at the decision point. The peak area against the IS ratio was used to normalize the signal. Replicate extractions are deposited on a LazWell plate and dried before analysis. No overlapping at the decision point is observed for all curves and the CV% was below 15% for within-run experiments. A dry and wet stability of sample extracts were performed. Precision criteria were applied. All results are within the acceptable criteria range. Oral fluids are collected from eight different volunteers. Samples are screened to verify the presence of each analyte (all samples were negative). Drugs are spiked at 50% cut-off (QC-L) and 200% cut-off (QC-H) and screened as unknown to verify the method sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy. A percentage of 100% was obtained for all validation parameters of all drugs. Luxon Ion Source® combined to a Shimadzu 8060 mass spectrometer system allows ultra-fast (8 seconds per sample) screening of a SAMHSA drug panel in oral fluid using a simple and automated sample preparation method.

Isotope Ratio Outlier Analysis (IROA) for HPLC-TOFMS-Based Metabolomics of Human Urine.

Metabolic fingerprinting by mass spectrometry aims at the comprehensive, semiquantitative analysis of metabolites. Isotope dilution, if successfully implemented, may provide a more reliable, relative quantification. Therefore, the 13C labeled yeast extract of the IROA TruQuant kit was added as an internal standard (IS) to human urine samples measured in full-scan mode on a high-performance liquid chromatography-time-of-flight mass spectrometer (HPLC–TOFMS) system. The isotope ratio approach enabled the analysis of 112 metabolites. The correlation with reference data did not improve significantly using 12C/13C ratios compared to absolute 12C peak areas. Moreover, using an intricate 13C-labeled standard increased the complexity of the mass spectra, which made correct signal annotation more challenging. On the positive side, the ratio approach helps to reduce batch effects, but it does not perform better than computational methods such as the “removebatcheffect” function in the R package Limma.

On the quest for novel bio-degradable plastics for agricultural field mulching.

Plasticulture, the practice of using plastic materials in agricultural applications, consumes about 6.7 million tons of plastics every year, which is about 2% of the overall global annual plastics production. For different reasons, plastic material used for agriculture is difficult to recycle. Therefore, most of it is either buried in fertile soils, thereby significantly causing deterioration of their properties, or, at best case, end in landfills where its half-life is measured in decades and even centuries. Hence, developing biodegradable plastic materials that are suitable for agricultural applications is a vital and inevitable need for the global human society. In our labs, two types of potentially biodegradable plastic polymer films were prepared and characterized imidazolium in terms of their bio-degradability. In the first approach, polymers made of ionic liquid monomers were prepared using photo radical induced polymerization. The second approach relies on formation of polyethylene-like n-alkane disulfide polymers from 1,ω-di-thiols through thermally activated air oxidation. These two families of materials were tested for their biodegradability in soils by using a simulation system that combines a controlled environment chamber equipped with a respirometer and a proton-transfer-reaction time of flight mass spectrometer (PTR-TOF-MS) system. This system provides a time-dependent and comprehensive fingerprint of volatiles emitted in the degradation process. The results obtained thus far indicate that whereas the ionic-liquid based polymer does not show significant bio-degradability under the test conditions, the building block monomer, 1,10-n-decane dithiol, as well as its disulfide-based polymer, are bio-degradable. The latter reaching, under basic soil conditions and in room temperature, ∼20% degradation within three months. These results suggest that by introduction of disulfide groups into the polyethylene backbone one may be able to render it biodegradable, thus considerably shortening its half-life in soils. Principal component analysis, PCA, of the data about the total volatiles produced during the degradation in soil indicates a distinctive volatile “fingerprint” of the disulfide-based bio-degradable products which comes from the volatile organic compounds portfolio as recorded by the PTR-TOF-MS. The biodegradation volatile fingerprint of this kind of film was different from the “fingerprint” of the soil background which served as a control. These results can help us to better understand and design biodegradable films for agricultural mulching practices.

Towards In-Situ Geochemical Analysis of Planetary Rocks and Soils by Laser Ablation/Ionisation Time-of-Flight Mass Spectrometry

Spectroscopic instruments were a part of payloads on orbiter and lander missions and delivered vast data sets to explore minerals, elements and molecules on air-less rocky planets, asteroids and comets on global and local scales. To answer current space science questions, the chemical composition of planetary rocks and soils at grain scale is required, as well as measurements of element (isotope) concentrations down to the part per million or lower. Only mass spectrometric methods equipped with laser sampling ion sources can deliver the necessary information. Laser sampling techniques can reduce the dimensions of the investigated sample material down to micrometre scale, allowing for the composition analysis of grain-sized objects or thin mineral layers with sufficiently high spatial resolution, such that important geological processes can be recognised and studied as they progressed in time. We describe the performance characteristics, when applied to meteorite and geological samples, of a miniaturised laser ablation/ionisation mass spectrometer (named LMS) system that has been developed in our group. The main advantages of the LMS instrument over competing techniques are illustrated by examples of high spatial (lateral and vertical) resolution studies in different meteorites, terrestrial minerals and fossil-like structures in ancient rocks for most elements of geochemical interest. Top-level parameters, such as dimension, weight, and power consumption of a possible flight design of the LMS system are presented as well.

Analytical scaling of Quadrupole Mass Spectrometer for Point of Care Applications

The best way to combat a disease is its early detection. A low-cost portable point of care (POC) device is required for early disease detection. A mass spectrometer (MS) is a golden analytical technique to diagnose many diseases. Conventional mass spectrometers are bulky and costly and limited to expensive laboratory setups. In the present paper, a POC-type quadrupole mass spectrometer (QMS) system is proposed for the early detection of diseases. The main component of QMS that makes it bulky and costly is the vacuum system. The length of the quadrupole filter determines its resolution, and the vacuum level is a function of its length. Hence, both length and vacuum levels are optimized without compromising resolution. The size of the quadrupole rods is reduced to 26 mm at 0.1 pascal pressure for portable applications. This optimized QMF is designed and simulated in COMSOL Multiphysics. The system's vacuum level is designed so that a single rotary pump can serve the purpose without any turbopump. A closed-form expression for mass resolution, pressure, and frequency is also derived.

The Exploration of the Thermococcus barophilus Lipidome Reveals the Widest Variety of Phosphoglycolipids in Thermococcales.

One of the most distinctive characteristics of archaea is their unique lipids. While the general nature of archaeal lipids has been linked to their tolerance to extreme conditions, little is known about the diversity of lipidic structures archaea are able to synthesize, which hinders the elucidation of the physicochemical properties of their cell membrane. In an effort to widen the known lipid repertoire of the piezophilic and hyperthermophilic model archaeon Thermococcus barophilus, we comprehensively characterized its intact polar lipid (IPL), core lipid (CL), and polar head group compositions using a combination of cutting-edge liquid chromatography and mass spectrometric ionization systems. We tentatively identified 82 different IPLs based on five distinct CLs and 10 polar head group derivatives of phosphatidylhexoses, including compounds reported here for the first time, e.g., di-N-acetylhexosamine phosphatidylhexose-bearing lipids. Despite having extended the knowledge on the lipidome, our results also indicate that the majority of T. barophilus lipids remain inaccessible to current analytical procedures and that improvements in lipid extraction and analysis are still required. This expanded yet incomplete lipidome nonetheless opens new avenues for understanding the physiology, physicochemical properties, and organization of the membrane in this archaeon as well as other archaea.