Ammonium Methanol Research Articles

Formation of zinc tetraammine difluoride and dinitrate and conversion to zinc oxide and zinc hydroxyfluoride under ambient conditions

The zinc tetraammine complexes [Zn(NH3]4]F2 (ZAF) and [Zn(NH3]4](NO3)2 (ZAN) have been isolated from methanolic ammonia and characterized by single crystal X-ray diffraction and Raman spectroscopy. As determined from Raman data, the tetrahedral structure of the zinc tetraammine cation complex is sustained in solutions that contain high concentrations of ammonia. Dilution of ZAF or ZAN solutions in bulk water results in the deposition of ZnO as determined by X-ray powder diffraction (XRD). Lower dilution, as when aqueous ZAF is applied to wet surfaces, results in Zn(OH)F deposition as identified by XRD. These mineral products are readily obtained from zinc tetraammine solutions under ambient conditions and lend themselves to biomedical and materials applications.

Synthesis, Characterization and Antibacterial Activity of Novel 2‐Oxo‐1,2‐dihydro‐1′H‐spiro[indoline‐3,2′‐quinazoline]‐4′‐carbohydrazones

AbstractTreatment of isatin with ammonia in methanol under reflux, followed by hydrazine substitution of the methoxy group afforded isamic hydrazide in up to 79 % yield. Subsequent condensation of isamic hydrazide with selected aromatic ketones and aldehydes gave access to novel 2‐oxo‐1,2‐dihydro‐1′H‐spiro[indoline‐3,2′‐quinazoline]‐4′‐carbohydrazones (4–11) in yields between 59 % and 74 %. Detailed structural analysis of synthesized compounds was done using spectroscopic techniques. Antibacterial screening of the hydrazone derivatives (4–11) demonstrated broad‐spectrum activity against evaluated bacterial strains, with inhibition zones ranging from 10 to 32 mm. Specifically, compound 9 exhibited superior activity compared to the standard streptomycin against various bacterial strains, including B. polymyxa (LIO), B. cereus (NCBI 6349), C. pyogenes (LIO), B. subtilis (NCBI 3610), S. aureus (NCBI 8588), E. coli (NCIB 86), P. aeruginosa (NCIB 950), and K. pneumoniae (NCIB 418). Moreover, the inhibitory concentrations of compound 9 were lower than those of streptomycin, underscoring its efficacy as a potential antibacterial agent. These findings suggest that the synthesized hydrazone derivatives possess significant potential as novel and effective antibacterial agents, warranting further exploration in the field of antibacterial drug development.

Recent Research in Solar-Driven Hydrogen Production

Climate concerns require immediate actions to reduce the global average temperature increase. Renewable electricity and renewable energy-based fuels and chemicals are crucial for progressive de-fossilization. Hydrogen will be part of the solution. The main issues to be considered are the growing market for H2 and the “green” feedstock and energy that should be used to produce H2. The electrolysis of water using surplus renewable energy is considered an important development. Alternative H2 production routes should be using “green” feedstock to replace fossil fuels. We firstly investigated these alternative routes through using bio-based methanol or ethanol or ammonia from digesting agro-industrial or domestic waste. The catalytic conversion of CH4 to C and H2 was examined as a possible option for decarbonizing the natural gas grid. Secondly, water splitting by reversible redox reactions was examined, but using a renewable energy supply was deemed necessary. The application of renewable heat or power was therefore investigated, with a special focus on using concentrated solar tower (CST) technology. We finally assessed valorization data to provide a tentative view of the scale-up potential and economic aspects of the systems and determine the needs for future research and developments.

Study on ammonia/methanol blends with ammonia cracking for low-carbon combustion and NO reduction

This work aims to study the ammonia/methanol blended fuel with ammonia cracking in lean-burn condition. Ammonia on-line cracking to produce hydrogen production has the potential to realize the high-efficiency combustion. A new ammonia/methanol/hydrogen mechanism was updated and simplified using several reduction methods to optimize the computation time in 3D simulation. Visualization measurements in constant volume combustion chamber (CVCC) for flame propagation and NO generation were conducted, and 3D computational fluid dynamics (CFD) modeling was also established with the simplified mechanism simultaneously to investigate the impact of methanol addition and ammonia cracking in the lean-burn mode. The findings showed that methanol addition and ammonia cracking can significantly improve the combustion rate, and 60%ammonia/40%methanol with ammonia cracking ratio of 90% (N60R90) at equivalence ratio (ER) of 0.7 yields the similar LBV as pure methanol at ER of 1.0 in laminar burning condition. Its ER can be extended to 0.4 to obtain the similar level of LBV as pure ammonia at 1.0. The experiments and 3D simulations revealed that N60R90 at 0.4 yields the equivalent level of combustion rate as N60R0 at 0.8, while obtaining much lower NO emission. In addition, N60R100 at 0.4 without fuel-NO formation during the combustion can get ultra-low NO emission. This study provides the insights on low-carbon combustion strategy for ammonia cracking with low NO.

The synthesis and characterization of electron-poor glycosylamines and derived glycosylamides

This paper describes a unified approach toward diglycosylamines using methanolic ammonia. All the glycosylamines prepared have been fully characterized, and their anomeric configuration has been determined. The article presents a novel method for the N-acylation of diglycosylamines and other electron-poor glycosylamines, which employs nitromethane as a solvent in carboxylic anhydride acylation under acidic conditions. The feasibility of this transformation is represented by a wide range of reaction substrates. All glycosylamides are formed solely with β-configuration. These two reactions constitute a simple and effective route to the synthesis of a novel class of compounds with an N-glycosidic linkage.

Quick and Concise Nonaqueous Capillary Electrophoresis Approach for Simultaneous Separation and Determining Five Phytohormones

A new, quick and concise nonaqueous capillary electrophoresis approach has been matured to separate phytohormones involving indobutyric acid, indoleacetic acid, abscisic acid, 1-naphthaleneacetic acid and gibberellin. Using a running buffer composed of 85% methyl cyanide, 0.8% 1.0 M caustic soda and 20.0 mM methanol ammonium acetate, satisfactory separation of five phytohormone standards was achieved within 4 mins. The lowest detection limit was obtained for 1-naphthaleneacetic-acid (0.06 and#181;g/ml) and the highest for gibberellin (1.71 and#181;g/ml). The approach has been utilized for wheat bud samples with spiked 5 phytohormones using a solid phase extraction procedure, acquiring recovery percentage ranging from 95 to 102%.

Effects of Methanol–Ammonia Blending Ratio on Performance and Emission Characteristics of a Compression Ignition Engine

Sustainable ammonia is one of the leading candidates in the search for alternative clean fuels for marine applications. This paper aims to build a simulation model of a six-cylinder, four-stroke diesel engine to investigate the effects of increasing the ammonia proportion in methanol–ammonia fuel blends on engine performance and emissions. In the present study, the conditions of different speeds and different proportions of ammonia in fuel blends are investigated. The results show that the average effective pressure, brake power, and brake torque increase by about 5% with an increased ammonia substitution ratio. In terms of economic performance, the changes under medium and low speed conditions are not obvious. However, the change in high speed conditions is significant. The brake specific fuel consumption (BSFC) is reduced by 6.6%, and the brake thermal efficiency (BTE) is increased by 4%. It is found that the performance of the engine is best at medium speed. The best performance is achieved with higher efficiency and lower emissions. The present results can provide guidance for the optimization of ammonia–methanol blends and their applications in engines.

Rapid profiling of cytokinins using supercritical fluid chromatography coupled with tandem mass spectrometry

BackgroundThe determination of plant hormones is still a very challenging analytical discipline, mainly due to their low concentration in complex plant matrices. Therefore, the involvement of very sensitive high-throughput techniques is required. Cytokinins (CKs) are semi-polar basic plant hormones regulating plant growth and development. Modern methods for CK determination are currently based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), which enables the separation of CK isomeric forms occurring endogenously in plants. Here, ultra-high performance supercritical fluid chromatography coupled with tandem mass spectrometry (UHPSFC-MS/MS) was used for the simultaneous determination of 37 CK metabolites. ResultsThe chromatographic conditions were tested on three different columns with various retention mechanisms. Hybrid silica modified with 2-picolylamine was selected as the stationary phase. Several parameters such as column temperature, back pressure regulation, mobile phase composition and make-up solvent were investigated to achieve efficient separation of CK isomers and reasonable sensitivity. Compared to UHPLC-MS/MS, a 9-min chromatographic analysis using a mobile phase of supercritical CO2 and 5 mM ammonia in methanol represents a three-fold acceleration of total run time. The quantification limit of UHPSFC-MS/MS method was in the range of 0.03–0.19 fmol per injection and the method validation showed high accuracy and precision (below 15 % for most analytes). The method was finally applied to the complex plant matrix of the model plant Arabidopsis thaliana and the obtained profiles of CK metabolites were compared with the results from the conventional UHPLC-MS/MS method. SignificanceThe presented work offers a novel approach for quantification of endogenous CKs in plants. Compared to the conventional UHPLC-MS/MS, the total run time is shorter and the matrix effect lower for the key CK metabolites. This approach opens the opportunity to utilize UHPSFC-MS/MS instrumentation for targeted plant hormonomics including other plant hormone families.

An experimental and modeling study on the oxidation of ammonia-methanol mixtures in a jet stirred reactor

Methanol and liquid ammonia can form a mixture with better combustion quality. In order to investigate the ammonia (NH3)/methanol (CH3OH) mixture oxidation process, jet-stirred reactor (JSR) oxidation experiments were conducted at atmospheric pressure and temperature of 700–1200 K. The concentration of NH3 in the NH3/CH3OH mixture was 80%, 60%, and 40%, respectively, for equivalent ratios of 0.8, 1.0, and 1.2. By using synchronous vacuum ultraviolet photoionization mass spectrometry, important species (such as CH2O, CO, NO, NO2, N2O) involved in the oxidation reaction were identified and quantified. The original chemical kinetic model was validated and optimized based on experimental data, which improved the model's ability to predict NH3/CH3OH oxidation process (the overall improvement is approximately 81.3% compared to the original mechanism). The results demonstrated that methanol accelerated the rate of ammonia oxidation,and methanol was rapidly oxidized at high methanol content. The sensitivity analysis of reaction pathways with varying equivalent ratios revealed that HO2 generated a substantial amount of OH radicals and facilitated the oxidation of methanol and ammonia. During the oxidation of ammonia, nearly half of the NO produced NO2 through NO + HO2 = NO2 + OH, and about 60% of the NO came from the reduction reaction of NO2. More than 80% of the N2O was produced by NH2 + NO2 = N2O + H2O, and most of the N2O was converted to N2, while NH2 promoted the conversion of NOx to N2.

Commercialization of Ceres SteelCell® Technology for Power Generation and Electrolysis

Ceres’ unique metal supported SOC technology is increasingly establishing itself as the global standard for SOC, combining robustness, efficiency and low manufacturing cost. The technology is rapidly moving from demonstration to true volume production, with Robert Bosch GmbH in Germany and Doosan Fuel Cell in South Korea both having licenses to manufacture Ceres SteelCell® cells and stacks at the hundreds of MW per year scale with factories under construction. Ceres currently have manufacturing plants making MW of stacks per year. Ceres SteelCell® technology has a wide range of applications in the power generation sector, with applications ranging from small scale <10kWe combined heat and power (CHP) systems to systems in the 100s of kW to MW range. An increasing area of interest for the application of SteelCell® technology is in the difficult-to-decarbonize marine sector, where the ability to operate efficiently on a range of fuels with much lower carbon emissions than the heavy diesel normally used for shipping. These include liquefied natural gas (LNG), methanol and liquid ammonia, as well as hydrogen. This is also driving development of higher-power systems in the MW range.An exciting new development is the application of Ceres SteelCell® technology to steam electrolysis. The inherent advantages of Ceres SteelCell® in terms of mechanical robustness, REDOX stability, low production cost and low-cost balance of plant are also applicable to electrolysis applications. In addition, there are potential thermodynamic advantages for integration of high temperature electrolysis with other industrial processes to utilize waste heat stemming from the lower temperature of operation of Ceres SteelCell® technology relative to competing SOC technologies as lower-grade heat is required. To demonstrate the capability of Ceres SteelCell® for electrolysis Ceres is developing a 1MWe-class steam electrolyzer demonstrator using a modular architecture of multiple smaller electrolysis cell modules (ECMs) which can operate standalone. Testing and validation of ECMs is currently ongoing prior to full system integration. These ECMs are built into a standard 40ft shipping container to form the complete system.Ceres has recently signed an agreement with Shell to operate one of these 1MW-class systems at Shell’s R&D center in Bangalore, India running for 3 years from 2023. In addition to gaining valuable experience in plant operation the hydrogen generated will be used for industrial processes on the site.

Commercialization of Ceres SteelCell® Technology for Power Generation and Electrolysis

Ceres’ SteelCell® technology is establishing itself as the global standard for SOC. The technology is rapidly moving to volume production, with Robert Bosch GmbH in Germany and Doosan Fuel Cell in South Korea having licenses to manufacture Ceres SteelCell® cells and stacks at the hundreds of MW per year scale. Ceres SteelCell® technology has multiple power generation applications ranging from small scale <10kWe combined heat and power (CHP) systems to 100s of kW to MWs. An increasing area of interest for the application of Ceres SteelCell® technology is the marine sector operating efficiently on a range of low-carbon fuels including liquefied natural gas (LNG), methanol and liquid ammonia, as well as hydrogen. This is also driving development of systems in the MW range. An exciting new development is the application of Ceres SteelCell® technology to steam electrolysis. Ceres has recently signed an agreement with Shell to operate a 1MW-class electrolyzer in Bangalore, India, running for 3 years from 2023.

Simultaneous Determination of Ceftazidime in Three Different Pharmaceutical Preparations Combined with Either Tazobactam, Tobramycin or Sulbactam by HPTLC-Spectrodensitometric Method.

A new, simple hight performance thin layer chromatography (HPTLC)-Spectrodensitometric strategy was created and approved for the synchronous estimation of four antibacterial specialists: ceftazidime (CEF), tazobactam (TAZ), tobramycin (TOB) and sulbactam (SUL). The four compounds were separated on TLC aluminum plates covered with silica gel 60F254, using chloroform-acetonitrile-methanol-ammonia (4:1:0.5:0.15, v/v/v/v) as a mobile phase at 254nm. Linear correlation was obeyed over the concentration ranges of 12.0-72.0, 2.0-12.0, 3.0-18.0 and 10.0-50.0μgmL-1 for CEF, TAZ, TOB and SUL, respectively. The proposed approach is efficient, repeatable and convenient as a flexible method for the quality control of diverse combinations of these pharmaceuticals in various pharmaceutical preparations, with high percent recoveries that are highly consistent with labeled data. When the findings of the proposed technique were compared to those of the comparison methods, there were no critical contrasts in terms of precision and accuracy.

Separation and determination of triadimefon and its metabolites triadimenol enantiomers in fruit puree by supercritical fluid chromatography.

A method was established for the separation and determination of triadimefon and its metabolite triadimenol enantiomer residues in major complementary fruit puree for infants and young children (banana puree, pineapple puree and grape puree) by supercritical fluid chromatography. After the samples were extracted with acetonitrile and purified with solid phase extraction cartridge, Acquity Trefoil CEL2 chiral chromatographic column was adopted for separation, and gradient elution was conducted at the flow rate of 1.0 mL/min under the mobile phase of supercritical carbon dioxide - 0.5% ammonia methanol; the detection wavelength was 220 nm and quantification was conducted with the external standard method. The limits of quantitation of triadimefon and triadimenol enantiomers were both 0.05 mg/kg, the linear ranges were 0.5-50 mg/L, and the linear correlation coefficients were greater than 0.9993. The recoveries in the spiked samples at 0.05, 0.2 and 3.0 mg/kg were from 80.1 to 106%, and the relative standard deviation reached 3.3-7.6%. The method is efficient, rapid, reproducible, and environmentally friendly, enabling accurate analysis of pesticide enantiomers, which can detect the enantiomer residues of triadimefon and its metabolite triadimenol in major complementary fruit puree for infants and young children. This article is protected by copyright. All rights reserved.

Separation of pyrrolizidine alkaloids in different Senecio species using ultra-high performance supercritical fluid chromatography

Different Senecio species, especially S. inaequidens – a neophyte native to South Africa – have widely spread across Europe and now are found worldwide. The entire genus is known to contain toxic pyrrolizidine alkaloids (PAs), which renders them a possible health hazard to humans and livestock. As they can enter the food chain or occur as contaminants in herbal crops and phytopharmaceutical formulations (e.g. teas), efficient and straightforward assays for their qualitative and quantitative analysis are in high demand. Different techniques have been used for this purpose, most commonly HPLC or GC. As the analysis of PAs is a challenging task, alternative methodologies like ultra-high performance SFC (UHPSFC) may offer an additional benefit in terms of their separation efficiency and orthogonal selectivity. In this study an UHPSFC approach for the simultaneous determination of six PAs (free bases as well as N-oxides) is presented, which achieved the baseline separation of all standard compounds in seven min. Optimal separation was carried out in gradient mode on a Torus™ DEA column with 0.05% ammonia in methanol as modifier. The column temperature was 25 °C, ABPR 1900 psi and flow rate 1.1 mL/min, with a detection wavelength of 215 nm. The assay was validated and fulfilled all ICH criteria exhibiting good linearity (R2 ≥ 0.9994), precision (inter-day variance ≤ 3.67%, intra-day variance ≤ 3.92%) and recovery rates (96.3–104.1%), with detection limits typical for SFC-PDA (≤ 4.24 µg/mL). Furthermore, it could conveniently be coupled to MS-detection, which increased the sensitivity significantly. To confirm practical suitability of the method, different Senecio samples were analyzed, indicating a high qualitative as well as quantitative difference in their PA profile (e.g. total amounts of PA between 0.09 and 4.63 mg/g).

Improvement in Ammonia, Hydrogen, and Methyl Formate Synthesis Process by Employing Multiobjective Optimization of a Novel Multifunctional Membrane Reactor

This investigation analyzes the simultaneous production of hydrogen and ammonia as carbon-free energy carriers and methyl formate (MF) as a widely used chemical intermediate in a multifunctional membrane reactor (MFMR). The MFMR, based on Le Chatelier’s principle, has the advantage of changing the thermodynamic equilibrium by direct thermal coupling between ammonia synthesis and MF production and shifting the chemical equilibrium with the use of the Pd–Ag membrane. In the innovative configuration, the nitrogen conversion rate has been increased from 38.2 to 41.2% and the methanol conversion from 16.3 to 99.1%. Other benefits of the MFMR include providing the required energy for an endothermic reaction and eliminating a furnace and cooler in methanol dehydrogenation and ammonia synthesis reactors. Furthermore, it has been demonstrated that if the ammonia synthesis reaction is positioned at the center side of the MFMR, the nitrogen and methanol conversion are, respectively, 1.32 and 7.34% higher than when the reaction is located at the outer side of the MFMR. Likewise, the effect of operational process parameters such as inlet flow rates, inlet temperatures, and membrane thickness on the performance of each reaction has been studied. Utilizing multiobjective optimization (MOO), it has been observed that ammonia and MF production yields can reach 20.3 and 24.1%, respectively.

An Efficient Undergraduate Synthesis of the Exorbitantly Priced Lambert–Eaton Myasthenic Syndrome Drug Amifampridine

An efficient synthesis of the exorbitantly priced Lambert–Eaton myasthenic syndrome drug amifampridine was developed and applied in the second-semester undergraduate organic chemistry laboratory. The two-step synthesis entails a nucleophilic aromatic substitution reaction of commercial 4-chloro-3-nitropyridine with methanolic ammonia to afford 4-amino-3-nitropyridine. Subsequent palladium-catalyzed nitro reduction provides amifampridine in high yield and purity. Amifampridine can alternatively be prepared by advanced undergraduate students in four linear steps beginning with 4-hydroxypyridine. Nitration of 4-hydroxypyridine to 4-hydroxy-3-nitropyridine and subsequent treatment with phosphoryl chloride provides the intermediate 4-chloro-3-nitropyridine, which is then subjected to the SNAr and reduction reactions to cleanly afford amifampridine without the need for column chromatography.

From fossil to green chemicals: sustainable pathways and new carbon feedstocks for the global chemical industry

Green methanol and green ammonia produced by renewable electricity and electricity-based hydrogen become the backbone for a defossilised global chemical industry.

Life Cycle Greenhouse Gas Emission Assessment for Using Alternative Marine Fuels: A Very Large Crude Carrier (VLCC) Case Study

The International Maritime Organization (IMO) has set decarbonisation goals for the shipping industry. As a result, shipowners and operators are preparing to use low- or zero-carbon alternative fuels. The greenhouse gas (GHG) emission performances are fundamental for choosing suitable marine fuels. However, the current regulations adopt tank-to-wake (TTW) emission assessment methods that could misrepresent the total climate impacts of fuels. To better understand the well-to-wake (WTW) GHG emission performances, this work applied the life cycle assessment (LCA) method to a very large crude carrier (VLCC) sailing between the Middle East and China to investigate the emissions. The life cycle GHG emission impacts of using alternative fuels, including liquified natural gas (LNG), methanol, and ammonia, were evaluated and compared with using marine gas oil (MGO). The bunkering site of the VLCC was in Zhoushan port, China. The MGO and LNG were imported from overseas, while methanol and ammonia were produced in China. Four production pathways for methanol and three production pathways for ammonia were examined. The results showed that, compared with MGO, using fossil energy-based methanol and ammonia has no positive effect in terms of annual WTW GHG emissions. The emission reduction effects of fuels ranking from highest to lowest were full solar and battery-based methanol, full solar and battery-based ammonia, and LNG. Because marine ammonia-fuelled engines have not been commercialised, laboratory data were used to evaluate the nitrous oxide (N2O) emissions. The GHG emission reduction potential of ammonia can be exploited more effectively if the N2O emitted from engines is captured and disposed of through after-treatment technologies. This paper discussed three scenarios of N2O emission abatement ratios of 30%, 50%, and 90%. The resulting emission reduction effects showed that using full solar and battery-based ammonia with 90% N2O abatement performs better than using full solar and battery-based methanol. The main innovation of this work is realising the LCA GHG emission assessment for a deep-sea ship.

Rapid screening of 14 antibacterial drugs in anti-acne cosmetics using ion mobility spectrometry coupled with solid-phase extraction

The main methods currently used to detect illegally added chemicals in cosmetics include thin-layer chromatography, high performance liquid chromatography (HPLC), gas chromatography (GC), and liquid chromatography-mass spectrometry (LC-MS). Compared with other analytical techniques, these methods have the advantages of high sensitivity, specificity, and accuracy, all of which are required in practical detection work. However, they also present a number of limitations, such as long analysis times and requirements for skilled operators and strictly controlled laboratory environments. Supervision, a growing trend in market surveillance, requires rapid and effective methods to screen illegally added chemicals. The suspected samples are sealed for some time and then sent to the laboratory for further testing. Ion mobility spectrometry (IMS) is a new type of trace gas separation technology that was developed in recent years. The principle behind IMS is the separation and characterization of chemical species based on differences in the migration speed of their gas-phase ions under an electric field. As this technology has the advantages of miniaturization, easy operation, and quick responses, it is widely used in food and drug quality testing, as well as other related fields. However, it is rarely used in cosmetic detection, likely because the cosmetics matrix is highly complex, which can interfere with ion determination. Thus, optimizing the pretreatment process of cosmetics for IMS is important. In this work, solid-phase extraction (SPE) is combined with IMS to establish a method for the rapid screening of 14 antibacterial drugs in anti-acne cosmetics. The IMS detection parameters, sample extraction conditions, and SPE clean-up conditions (SPE column, type of leachate, type and volume of eluent) were studied and optimized in detail. The sample was extracted with 80%(v/v) acetonitrile aqueous solution (containing 0.2% (mass fraction) trichloroacetic acid), loaded onto an activated Oasis® MCX SPE column, leached with 3.0 mL of methanol, and eluted with 1.0 mL of 2% ammonia methanol solution. The eluate was then directly injected into the IMS instrument. The IMS parameters were as follows: positive ion source voltage=2200 V, transfer tube voltage=8000 V, inlet temperature=180 ℃, transfer tube temperature=180 ℃, ion gate voltage=50 V, gate voltage pulse width=85 μs, and migration gas flow rate=1.2 L/min. The migration times for the 14 antibacterial drugs ranged from 11 to 17 ms, and the detection limits for the target compounds ranged from 0.2 to 1.2 μg/g. Owing to the narrow linear range of IMS, a quantitative method employing HPLC was also established to optimize the SPE pretreatment step and verify the positive samples. Chromatographic separation was conducted on a Phenomenex Luna C18 column (250 mm×4.6 mm, 5 μm), with a column flow rate of 1.0 mL/min and gradient elution with mobile phases A (0.01 mol/L potassium dihydrogen phosphate adjusted to pH 4.0 with phosphoric acid) and B (acetonitrile). The column temperature was set to 35 ℃, and the injection volume was fixed at 5 μL. A total of 25 cosmetics samples were screened, and one positive sample was found to be consistent with the results of HPLC. The proposed method is fast, simple, and efficient, and it can be used for the rapid screening of the 14 antibacterial drugs in anti-acne cosmetics. Pretreatment can significantly reduce the influence of the cosmetic matrices on the determination results, improve instrument sensitivity, and effectively decrease the occurrence rate of false positives and negatives. The technique developed in this work can improve the efficiency of screening for illegally added chemicals and expand the applications of IMS for detecting various chemicals in complex matrices, such as cosmetics.

Cost assessment of alternative fuels for maritime transportation in Ireland

In this study, we investigated the cost-effectiveness of four alternatives: Liquified Natural Gas (LNG), methanol, green hydrogen, and green ammonia, for the case of top 20 most frequently calling ships to Irish ports in 2019, through the Net Present Value (NPV) methodology, incorporating the benefits incurred through saved external, carbon tax and conventional fuel costs. LNG had the highest NPV (€6,166 million), followed by methanol (€1,705 million) and green hydrogen (€319 million). Green ammonia utilisation (as a hydrogen carrier) looks inviable due to higher operational costs, resulting from its excessive consumption (i.e., losses) during the cracking and purifying processes and its lower net calorific value. Green hydrogen remains the best option to meet future decarbonisation targets, although, a further reduction in its current fuel price (by 60%) or a significant increment in the proposed carbon tax rate (by 275%) will be required to improve its cost-competitiveness over LNG and methanol.