RESUMEN

Honey is well-known as a food product that is rich in active ingredients and is very popular among consumers. Free amino acids (FAAs) are one of the important nutritional components of honey, which can be used not only as a nutritional indicator of honey but also as an indicator of plant source identification. In this study, the contents of 20 FAAs in seven types of honey from 11 provinces in China were examined for the first time. The 20 FAAs were analyzed by ultra-performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS). By analyzing 93 honey samples from seven types of honey, the FAAs were found to range from 394.4 mg/kg (linden honey) to 1771.7 mg/kg (chaste honey). Proline ranged from 274.55 to 572.48 mg/kg, and methionine was only present in some of the linden honey, chaste honey, acacia honey, and rape honey. Evaluated by amino acid principal component analysis, multifloral grassland honey had the highest overall evaluation score, acacia and jujube honey were the most similar, while chaste honey was the least similar to the other types of honey. In addition, DNA was extracted from 174 Xinjiang grassland honey samples and different plant leaves for PCR and sequencing to identify the species of nectar plants. As a result, 12 families and 25 species of honey plants were identified. The results confirmed the diversity of FAAs in dissimilar types and sources of honey. This study provides a reference for expanding honey quality standards and verifying the authenticity of honey.

RESUMEN

BACKGROUND: Honey aroma is one of its most important properties and it depends on the qualitative and quantitative composition of the volatile compounds. The volatile profile of honey could reveal its botanical origin to avoid a false characterization. Thus, it is of great significance to honey authentication. This study developed and validated a headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) method for simultaneous qualitative and quantitative analyses of 34 volatile components in honey. The developed method was applied to 86 honey samples from six different botanical origins, including linden honey, rape honey, jujube honey, vitex honey, lavender honey and acacia honey. RESULTS: The volatile fingerprints and quantitative results were simultaneously obtained by using the full scan and selected ion monitoring (SCAN+SIM) MS scanning mode. The limits of quantification (LOQs) and limits of detection (LODs) of 34 volatile compounds were in the ranges of 1-10 ng/g and 0.3-3 ng/g, respectively. And the spiked recoveries ranged between 70.6% and 126.2%, with the relative standard deviations (RSDs) not higher than 45.4%. A total of 98 volatile compounds were found with relative contents determined, and the 34 volatile compounds were determined with absolute concentrations. Based on the volatile fingerprints and the contents of volatile compounds, honey samples from six botanical origins were well classified by principal component analysis and orthogonal partial least-squares discrimination analysis. CONCLUSIONS: The HS-SPME-GC-MS method was successfully applied to achieve the volatile fingerprints of six types of honey and to quantitatively analyze 34 volatile compounds with satisfying sensitivity and accuracy. Chemometrics analysis showed significant correlations between honey types and volatiles. These results reveal the characteristics of volatile compounds in six types of unifloral honey and provide some supports for honey authentication. © 2023 Society of Chemical Industry.

Asunto(s)

Miel , Compuestos Orgánicos Volátiles , Cromatografía de Gases y Espectrometría de Masas/métodos , Miel/análisis , Microextracción en Fase Sólida/métodos , Compuestos Orgánicos Volátiles/química

RESUMEN

Potassium-ion batteries (PIBs) are prospective for energy storage systems owing to their low price and high operating voltage. Antimony-based electrode materials have the advantage of high capacity for PIBs, while suffering from huge volume expansion and inferior stability because of the large radius of K+. Therefore, developing suitable antimony-based electrode materials with high performance is highly challenging. Herein, self-assembled Sb2S3 nanoflowers on the surfaces of MXene (Ti3C2) flakes are synthesized through a solvothermal reaction along with a calcination method. The highly conductive two-dimensional Ti3C2 soft substrate could not only boost the charge transfer kinetics but also buffer the volumetric expansion of Sb2S3 effectively. In addition, the structural stability is enhanced because the Sb2S3 nanoflowers are in situ grown on Ti3C2 flakes through the strong interfacial coupling. Consequently, the Ti3C2-Sb2S3 anode exhibits a high reversible capacity of 461 mAh g-1 at 100 mA g-1, long cycling life (capacity retention of 79% for 500 cycles), and superior rate performance (102 at 2000 mA g-1). This work may provide a pathway for designing advanced materials for PIBs.

RESUMEN

This paper demonstrates a hybrid transparent electrode composed of a solution-processed silver-nanowire (AgNW) film coated by zinc oxide nanoparticles (ZnO-NPs) acting as a modified buffer layer. The effect of the ZnO-NPs' coating ratio on the performances of indium tin oxide (ITO)-free organic solar cells (OSCs) has been systematically investigated. The optimized ITO-free OSCs achieved a power conversion efficiency (PCE) of 2.85%, while flexible OSCs using the AgNW/ZnO-NP composite transparent electrode grown on a polyethylene terephthalate (PET) substrate showed a PCE of 2.2%.