Zhi Zeng

The antibiotic type organic structure pefloxacin binds well with europium (III) ions as a useful scaffold for assembling optical probes and allows energy transfer from ligand to metal ions through coordination linkages. This water‐soluble chemosensor demonstrated significant ‘off–on (red)’ changes from an alkaline to a neutral environment (pH 14–8). The emission changed from red to blue under acidic conditions (pH 7–2). The whole process was completely reversible and effective within the pH range 2 to 14. Moreover, this probe system exhibited distinct luminescence quenching upon the addition of Cu²⁺ or Fe³⁺. This general modular route will permit easy detection and the concept can be extended to a variety of quinolones for sensing purposes.

A novel porous polymer material with red emissions composed of a europium silica hybrid and polyurethane foam has been assembled. Its sensing properties in water have been investigated and the fluorescence of the foam was selectively quenched in the presence of Cu²⁺ (detection limit 3.4 μM) compared with other cation ions (Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Ba²⁺, Cr²⁺, Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Al³⁺, Pb²⁺ and Ag⁺). The high selectivity and sensitivity were attributed to the strong chelation of Cu²⁺ with nitrogen atoms of the ligand (L) and the photo-induced electron transfer effect. The luminescent polyurethane foam showed a good reusability (more than 10 times). Interestingly, the red emission can be switched “off” and “on” via the addition of copper ions and EDTA, respectively. Additionally, the tensile failure tests proved that higher mechanical strength could be achieved in the silica material reinforced polyurethane foam.

The essential oil of Adenosma indianum (Lour.) Merr. plays an important role in its antibacterial and antiphlogistic activities. In this work, the volatile components were extracted by steam distillation (SD) and headspace solid‐phase microextraction (HS‐SPME) and analysed by gas chromatography‐mass spectrometry (GC‐MS). A total of 49 volatile components were identified by GC‐MS, and the major volatile components were α‐limonene (20.59–35.07%), fenchone (15.79–31.81%), α‐caryophyllene (6.98–10.32%), β‐caryophyllene (6.98–10.19%), and piperitenone oxide (1.96–11.63%). The comparison of the volatile components from A. indianum (Lour.) Merr. grown in two regions of China was reported. Also, the comparison of the volatile components by SD and HS‐SPME was discussed. The results showed that the major volatile components of A. indianum (Lour.) Merr. from two regions of China were similar but varied with different extraction methods. These results were indicative of the suitability of HS‐SPME method for simple, rapid, and solvent‐free analysis of the volatile components of the medicinal plants.

The chemical compositions of volatile components from Magnolia biondii Pamp were determined by steam distillation (SD) and headspace solid phase micro-extraction (HS-SPME) followed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis. Fifty-six compounds were identified and the major volatile components were d-camphor (0.18-43.26%), 1,8-cineol (13.23-38.02%), α-terpineol (6.57-12.29%) and α-cadinene (5.53-15.15%). The comparison of the volatile components from M. biondii Pamp harvested in three regions of China was investigated. Also, the comparison of volatile components by SD and HS-SPME methods in term of isolation time, plant-consuming and chemical compositions was discussed as well. The percentages of the volatile components by HS-SPME method were found to be large difference from the corresponding one by SD method. HS-SPME technique was much faster than SD (60 min (HS-SPME)/420 min (SD)). Although the aromatic profiles between HS-SPME and SD methods showed several quantitative differences, HS-SPME may be applied routinely to analyze aromatic and medicinal plants.

The determination of γ-nonalactone as one of the important odor-active compounds in freshly cooked non-scented rice is reported. It was evaluated by gas chromatography-olfactometry (GC-O) analysis and identified by gas chromatography-mass spectrometry (GC-MS) analysis in the headspace above the freshly cooked non-scented rice samples extracted by using a modified headspace solid-phase microextraction (SPME) method. This component had a mass spectrum with a characteristic ion peak at m/z 85 (100%) and a linear retention index (RI) of 2,023 on a DB Wax column, consistent with those of an authentic sample of γ-nonalactone. The odor characterization of a strong, sweet, coconut-like aroma of this compound was also validated by GC-O comparison with the authentic compound.