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Microplastics (MPs) pollution has drawn increasing concern due to its widespread occurrence and potential risks in the environment. The reliable methods and instruments for fast analysis of microplastics (MPs) less than 5 mm are urgently needed. In this study, a new method based on custom-made portable pyrolysis-mass spectrometry (Pyr-MS) is developed, which enables rapid identification and mass related quantification of MPs. MPs are decomposed in the compact pyrolyzer and then directly analyzed in the portable MS by the chemical fingerprints of polymers including characteristic ions and their special ratio. It avoids the complex extraction and separation procedures of the pyrolysis/thermogravimetric–gas chromatography–mass spectrometry (Pyr/TGA-GC-MS), realizes the rapid analysis of MPs in 5 min, and thus can practically apply to a large number of MPs samples. In comparison to Fourier transform infrared spectroscopy (FT-IR) and Raman, this method is not limited by the shape, size, and color of MPs. Four common plastics including polyethylene (PE), polypropylene (PP), polystyrene (PS), and poly­(methyl methacrylate) (PMMA) were investigated to verify the feasibility of this method. The environmental MPs samples collected from a beach were successfully identified and quantified, demonstrating the simplicity and practicality of this approach. The influence of plastics aging on the chemical fingerprints and the potential of mixed plastics detection by Pyr-MS are also assessed. The portable Pyr-MS could provide a promising tool for in-field analysis of MPs such as ship-based marine MPs surveys.

One new triterpenoid saponin and two lupane-derived triterpenes were isolated from Acanthopanax sessiliflorus fruits. The structures of the two new compounds were elucidated as 3- O-[(alpha- L-arabinopyranosyl)-(1 --> 2)]-[ beta- D-glucuronopyranosyl-6- O-methyl ester]-olean-12-ene-28-olic acid (1) and (1 R,11 alpha,22 alpha)-1,4-epoxy-11,22-hydroxy-3,4-secolupane-20(30)-ene-3,28-dioic acid (3) on the basis of spectral analysis, including MS, (1)H-NMR, (13)C-NMR, DEPT, HMBC, HMQC and NOESY. The structure of the other new natural product was elucidated as (1 R,11 alpha)-1,4-epoxy-11-hydroxy-3,4-secolupane-20(30)-ene-3,28-dioic acid (2). All these compounds showed antiplatelet aggregation activity on ADP-induced platelet aggregation.

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Herein we report the study of electrochemiluminescence (ECL) generation by tris(2,2'bipyridyl)ruthenium (Ru(bpy) 3 2 + ) and five tertiary amine coreactants. The ECL distance and lifetime of coreactant radical cations were measured by ECL selfinterference spectroscopy. And the reactivity of coreactants was quantitatively evaluated in terms of integrated ECL intensity. By statistical analysis of ECL images of single Ru(bpy) 3 2 + -labeled microbeads, we propose that ECL distance and reactivity of coreactant codetermine the emission intensity and thus the sensitivity of immunoassay. 2,2-bis(hydroxymethyl)-2,2',2''-nitrilotriethanol (BIS-TRIS) can well balance ECL distancereactivity trade-off and enhance the sensitivity by 236 % compared with tri-n-propylamine (TPrA) in the beadbased immunoassay of carcinoembryonic antigen. The study brings an insightful understanding of ECL generation in bead-based immunoassay and a way of maximizing the analytical sensitivity from the aspect of coreactant.

The chemistry of abiotic synthesis of peptides in the context of their prebiotic origins is a continuing challenge that arises from thermodynamic and kinetic constraints in aqueous media. Here we reported a strategy of microdroplets’ mass spectrometry for peptide bonds formed from pure amino acids or a mixture in the presence of phosphoric acids in aqueous microdroplets. In contrast to bulk experiments, the condensation reactions proceed spontaneously under ambient conditions. The microdroplet gave a negative free-energy change (ΔG ∼ −1.1 kcal/mol), and product yields of ∼75% were obtained at the scale of a few milliseconds. Experiments in which nebulization gas pressure and external charge were varied established dependence of peptide production on the droplet size that has a high surface-to-volume ratio. It is concluded that the condensation reactions occurred at or near the air–water interfaces of microdroplets. This aqueous microdroplets approach also provides a route for chemistry synthesis in the prebiotic era.

A simple and effective approach to studying the mechanism of electrooxidation of aniline (ANI) is reported in this paper. It was accomplished by an innovative electrochemistry (EC)-mass spectrometry (MS) coupling, which can sample directly from a droplet-scale reacting electrolyte for mass spectrometric analysis. With this setup, the polymer chain growth of ANI could be monitored in situ and in real-time. The short-lived radical cations (ANI, m/ z 93.06) as well as the soluble dimer ( m/ z 183.09) and oligomers ( m/ z 274.13, 365.18, ...) were successfully captured. Using the EC-MS and tandem mass spectrometry, the dimers produced by head-to-tail (4-aminodiphenylamine), head-to-head (hydrazobenzene), and tail-to-tail (benzidine) coupling of radical cations were found in the same polymerization process. Moreover, the EC-MS method was also applicable for determining the propagation speed of ANI when applying different electrolyte salts and oxidizing potentials.