The Role of Aqueous Aerosols in the “Glyoxylate Scenario”: An Experimental Approach

The origin of life is one of the fundamental questions in science. Eschenmoser proposed the “glyoxylate scenario”, in which plausible abiotic synthesis pathways were suggested to be compatible with the constraints of prebiotic chemistry. In this proposal, the stem compound is HCN. In this work, we explore the “glyoxylate scenario” through several syntheses of HCN polymers, paying particular attention to the role of the aqueous aerosols, together with statistical methods, as a step to elucidate the synthetic problem of the origin of life. The soluble and insoluble HCN polymers synthetized were analyzed by GC‐MS. We identified, for the first time, glyoxylic acid in these polymers, together with some constituents of the reductive tricarboxylic acid cycle, amino acids and several N‐heterocycles. The findings presented herein, as the first global approach to the “glyoxylate scenario”, give full effect to this hypothesis and prove that aqueous aerosols could play an important role in this plausible scene of the origin of life.     

High‐resolution stimulated Raman spectroscopy and analysis of line positions and assignments for the ν2 and ν3 bands of 13C2H4

High‐resolution stimulated Raman spectra of¹³C₂H₄ in the regions of the ν₂ and ν₃ Raman active modes have been recorded at two temperatures (145 and 296 K) based on the quasi continuous‐wave (cw) stimulated Raman spectrometer at Instituto de Estructura de la Materia IEM‐CSIC in Madrid. A tensorial formalism adapted to X₂Y₄ planar asymmetric tops with D_2h symmetry (developed in Dijon) and a program suite called D_2hTDS (now part of the XTDS/SPVIEW spectroscopic software) were proposed to analyze and calculate the high‐resolution spectra. A total of 103 and 51 lines corresponding to ν₂ and ν₃ Raman active modes have been assigned and fitted in wavenumber with a global root mean square deviation of 0.54 × 10⁻³ and 0.36 × 10⁻³ cm⁻¹, respectively. Due to the fact that the Raman scattering effect is weak, we did not perform in this contribution the line intensities analysis. Copyright © 2016 John Wiley & Sons, Ltd.     

Application of a group contribution equation of state for the thermodynamic modeling of binary systems (gas + ionic liquids) with bis[(trifluoromethyl)sulfonyl]imide anion

The properties of ionic liquids (ILs) can be modified by appropriate selection of cations and anions. Even if an infinite number of ionic liquids can be generated, only a limited number of families of anions and cations are used. The group contribution equation of state (GC-EoS) is a promising method for calculating the phase behavior of systems with ILs. If the parameters of the characteristic functional group of a IL family are fitted by using data of a reduced number of ILs of the family, then the phase behavior of all the ILs of the same family can be predicted using exclusively the data of the pure components. Previously, the parameters of the IL families with an imidazolium-based cation and the anions PF₆, BF₄NO₃, and Tf₂N were fitted to experimental data [19], and some ternary systems (CO₂ + organics + ionic liquid [bmim][BF₄]) were also modeled [22]. In this work, the GC-EoS was used to calculate phase behavior of gases {(CO₂, O₂, or SO₂) + ionic liquids} with Tf₂N anion and cations of the families 2,3-dimethyl-imidazolium, 1-alkyl-1-methyl-pyrrolidinium, and 1-alkyl-3-methyl-pyridinium. The GC-EoS was able to reproduce experimental data with deviations of the same order of experimental uncertainty. With the correlated parameters it will be possible to predict the phase behavior of systems with ILs of the families considered in this work.     

Endogenous arene hydroxylation promoted by copper(I) cluster helicates

A novel neutral triple-stranded hexanuclear copper(I) cluster helicate [Cu(I)(6)L(3)]·2CH(3)CN derived from a thiosemicarbazone ligand could be synthesized and crystallographically characterized. The MALDI mass spectrum of this complex suggests that the tetranuclear copper(I) cluster helicate [Cu(I)(4)L(2)] is also present in solution. These copper(I) cluster helicates are capable, in the presence of O(2), of hydroxylating the arene linker of their supporting ligand strands. The resulting dinuclear complex [Cu(II)(2)L'(OH)] is formed by two copper(II) centers, a new ligand arising from the hydroxylation reaction, and one hydroxide group. The magnetic investigation of this compound shows a strong antiferromagnetic coupling between the two Cu(II) centers. The kinetic studies for the hydroxylation process show values of ΔH(≠)=-70 kJ mol(-1), similar to those mediated by the tyrosinase enzymes.     

Determination of ketamine and amphetamines in hair by LC/MS/MS

A liquid chromatography-tandem mass spectrometry method was developed for the determination of ketamine (with its metabolite norketamine) and some amphetamines (amphetamine, methamphetamine, methylenedioxyamphetamine, and 3,4-methylenedioxymethamphetamine). This method was developed to determine these compounds in hair and is able to simultaneously quantify all of them in human hair. Hair samples (20 mg) were washed and pulverized, and an extraction with formic acid (0.01%) and ultrasonication for 4 h was used. Deuterated analogs of the analytes were used as internal standards for quantification. Linearity from 0.5 to 25 ng/mg was obtained for both ketamine (and norketamine) and amphetamines with correlation coefficients exceeding 0.99. The limit of detection and the limit of quantification obtained were 0.1 and 0.5 ng/mg, respectively, for ketamine and amphetamines. A total of 25 hair samples from known drug abusers (relating to designer drug consumption or consumption of amphetamines) were examined by this validated method. The results show that the proposed method is suitable for testing these drugs in a single sample of hair. In addition, it is simpler and faster than analysis by conventional methods such as gas chromatography-mass spectrometry, which usually require a more laborious extraction procedure and, in most of cases, an additional derivatization process.     

Analytical applications of a carbon nanotubes composite modified with copper microparticles as detector in flow systems

A simple microchip electrophoresis-laser-induced fluorescence device was constructed and used for separation and determination of catecholamines. On the fabricated glass chip, an extra optical fiber insertion channel, which was perpendicular and extremely close to the separation channel, was directly integrated by nothing operations more than design features on the photomask. The utilization of optical fiber to transmit the excitation light and the integration fiber channel make the fluorescence detection system simple and disposable. For electrophoresis, optimization of separation conditions was investigated for reaching high separation efficiency and sensitivity. A separation efficiency as high as 10⁶ theoretical plate numbers could be obtained for the analytes.