A robust sheath‐flow CE‐MS interface for hyphenation with Orbitrap MS

The hyphenation of capillary electrophoresis with high‐resolution mass spectrometry, such as Orbitrap MS, is of broad interest for the unambiguous and exceptionally sensitive identification of compounds. However, the coupling of these techniques requires a robust ionization interface that does not influence the stability of the separation voltage while coping with oxidation of the emitter tip at large ionization voltages. Herein, we present the design of a sheath‐flow CE‐ESI‐MS interface which combines a robust and easy to operate set‐up with high‐resolution Orbitrap MS detection. The sheath liquid interface is equipped with a gold coated electrospray emitter which increases the stability and overall lifetime of the system. For the characterization of the interface, the spray stability and durability were investigated in dependence of the sheath‐flow rate, electrospray voltage, and additional gold coating. The optimized conditions were applied to a separation of angiotensin II and neurotensin resulting in LODs of 2.4 and 3.5 ng/mL

Phosphorylation in liquid sulfur dioxide under prebiotically plausible conditions

In nature, organophosphates provide key functions such as information storage and transport, structural tasks, and energy transfer. Since condensations are unfavourable in water and nucleophilic attack at phosphate is kinetically inhibited, various abiogenesis hypotheses for the formation of organophosphate are discussed. Recently, the application of phosphites as phosphorylation agent showed promising results. However, elevated temperatures and additional reaction steps are required to obtain organophosphates. Here we show that in liquid sulfur dioxide, which acts as solvent and oxidant, efficient organophosphate formation is enabled. Phosphorous acid yields up to 32.6% 5′ nucleoside monophosphate, 3.6% 5′ nucleoside diphosphate, and the formation of nucleoside triphosphates and dinucleotides in a single reaction step at room temperature. In addition to the phosphorylation of organic compounds, we observed diserine formation. Thus, we suggest volcanic environments as reaction sites for biopolymer formation on Early Earth. Because of the simple recyclability of sulfur dioxide, the reaction is also interesting for synthesis chemistry

Iron-Mediated Peptide Formation in Water and Liquid Sulfur Dioxide under Prebiotically Plausible Conditions

Peptides have essential structural and catalytic functions in living organisms. The formation of peptides requires the overcoming of thermodynamic and kinetic barriers. In recent years, various formation scenarios that may have occurred during the origin of life have been investigated, including iron(III)-catalyzed condensations. However, iron(III)-catalysts require elevated temperatures and the catalytic activity in peptide bond forming reactions is often low. It is likely that in an anoxic environment such as that of the early Earth, reduced iron compounds were abundant, both on the Earth's surface itself and as a major component of iron meteorites. In this work, we show that reduced iron activated by acetic acid mediates efficiently peptide formation. We recently demonstrated that, compared to water, liquid sulfur dioxide (SO2) is a superior reaction medium for peptide formations. We thus investigated both and observed up to four amino acid/peptide coupling steps in each solvent. Reaction with diglycine (G(2)) formed 2.0 % triglycine (G(3)) and 7.6 % tetraglycine (G(4)) in 21 d. Addition of G(3) and dialanine (A(2)) yielded 8.7 % G(4). Therefore, this is an efficient and plausible route for the formation of the first peptides as simple catalysts for further transformations in such environments

From amino acid mixtures to peptides in liquid sulphur dioxide on early Earth

The formation of peptide bonds is one of the most important biochemical reaction steps. Without the development of structurally and catalytically active polymers, there would be no life on our planet. However, the formation of large, complex oligomer systems is prevented by the high thermodynamic barrier of peptide condensation in aqueous solution. Liquid sulphur dioxide proves to be a superior alternative for copper-catalyzed peptide condensations. Compared to water, amino acids are activated in sulphur dioxide, leading to the incorporation of all 20 proteinogenic amino acids into proteins. Strikingly, even extremely low initial reactant concentrations of only 50 mM are sufficient for extensive peptide formation, yielding up to 2.9% of dialanine in 7 days. The reactions carried out at room temperature and the successful use of the Hadean mineral covellite (CuS) as a catalyst, suggest a volcanic environment for the formation of the peptide world on early Earth

Iron-mediated peptide formation in water and liquid sulfur dioxide under prebiotically plausible conditions

Peptides have essential structural and catalytic functions in living organisms. The formation of peptides requires the overcoming of thermodynamic and kinetic barriers. In recent years, various formation scenarios that may have occurred during the origin of life have been investigated, including iron(III)-catalyzed condensations. However, iron(III) catalysts require harsh conditions and the catalytic activity in peptide bond forming reactions is low. It is likely that in an anoxic environment such as that of the early Earth, reduced iron compounds were abundant, both on the Earth\u27s surface itself and as a major component of iron meteorites. Here we show, that reduced iron activated by acetic acid mediates efficiently peptide formation. We observed, both in water and liquid sulfur dioxide, up to four amino acid/ peptide coupling steps and the formation of up to decamers. In 21 days 4.1% triglycine G3 and 11.3% tetraglycine G4 were formed. Addition of G3 and dialanine A2 yielded 26.0% G4. Therefore, this is a highly efficient and plausible route for the formation of the first peptides as simple catalysts for further transformations in such environments