The traditional method of gas chromatography-mass spectrometry for monosaccharide component analysis with pretreatment of acetylation is described with slight modifications and verified in detail in this paper. It was then successfully applied to the quantitative analysis of component monosaccharides in polysaccharides extracted from the pine cones. The results demonstrated that the three pine cone polysaccharides all consisted of ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose in different molar ratios. According to the recovery experiment, the described method was proved accurate and practical for the analysis of pine cone polysaccharides, meeting the need in the field of chemical analysis of Pinus plants. Furthermore; the chemical characteristics, such as neutral sugar, uronic acids, amino acids, molecular weights, and antioxidant activities of the polysaccharides were investigated by chemical and instrumental methods. The results showed that the chemical compositions of the polysaccharides differed from each other, especially in the content of neutral sugar and uronic acid. In the antioxidant assays, the polysaccharide fractions exhibited effective scavenging activities on ABTS radical and hydroxyl radical, with their antioxidant capabilities decreasing in the order of PKP > PAP > PSP. Therefore, although the polysaccharide fractions had little effect on superoxide radical scavenging, they still have potential to be developed as natural antioxidant agents in functional foods or medicine.

Pinus koraiensis polysaccharides (PKP) were extracted by hot water from P. koraiensis pine cones. Five polysaccharide fractions named PKP-A, PKP-B, PKP-C, PKP-D and PKP-E were successfully separated at final ethanol concentrations of 30%, 50%, 60%, 70% and 80%, respectively. HPLC, FT-IR, GC-MS and automatic amino-acid analysis were applied to investigate their chemical characteristics. Monosaccharide component analysis indicated that the five fractions were all composed of d-ribose, l-rhamnose, l-arabinose, d-xylose, d-mannose, d-glucose and d-galactose, but their molar ratios were quite different. HPLC results revealed that the polysaccharides precipitated by higher concentrations of ethanol solution had lower molecular masses. Moreover, the antioxidant activities of the five fractions were studied on the basis of hydroxyl radical and ABTS radical scavenging tests. The five graded polysaccharide fractions exhibited good inhibitory power, and MTT tests in vitro showed the IC₅₀ of PKP-A and PKP-E were 1,072.5 and 2,070.0 μg·mL⁻¹, respectively. These results demonstrated that the PKP could be a potential source of natural antioxidants or dietary supplements.

In this study, we report a facile method for the preparation of molecularly imprinted polymer based graphene for the electrochemical detection of thiamethoxam residue. We choose p-vinylbenzoic acid as a functional monomer; it can be used to add recognition units and alkenyl units onto the surface of graphene via π–π interactions in just one step, effectively simplifying the reaction process. And an ultra-thin imprinting film (2 nm) is formed by reducing the addition step involving the alkenyl modifier. Due to the irreversible electrochemical reduction characteristics of thiamethoxam, the template can be removed easily using cyclic voltammetry scanning, without the need for organic solvents. The performance of the fabricated sensor was evaluated and the results indicated that the sensor exhibited excellent specific recognition abilities for thiamethoxam detection; the imprinting factor is 2.36. The peak current from thiamethoxam is linearly proportional to its concentration over the range from 0.5 to 20 μM, and the detection limit is 0.04 μM. The practical application of the sensor was also realized in the selective detection of thiamethoxam in real samples.

Allium chinense G. Don waste (ACGD) has an abundance of polysaccharides (ACGDP). Therefore, in this study, a method for extraction of ACGDP from ACGD by ultrasonic-assisted hot water extraction (UAE) based on ultrasonic cleaning equipment was developed. It was compared with hot water extraction (HWE) in terms of efficiency, energy consumption, and carbon emissions. Then, the mechanism of efficient extraction of ACGDP by UAE was further investigated. Finally, the physicochemical properties and in vitro activity of ACGDP were evaluated. The results suggested that the optimal conditions of UAE were temperature 53 ℃, time 34 min, power 280 W, liquid-solid ratio 22 mL/g, and the yield of ACGDP was 30.08 ± 0.21 %. Compared with HWE, UAE yield was increased by 30.10 %, time was shortened by 71.50 %, energy consumption was reduced by 77.33 %, and CO₂ emission was reduced by 82.56 %. UAE can efficiently extract ACGDP by changing the composition of the cell wall, destroying the microstructure, and reducing the particle size. In addition, ACGDP had better thermal stability and antioxidant activity, and exhibited positive hypoglycemic activity. Overall, this study provided a theoretical basis and new insights into the efficient extraction mechanism of UAE and the high-value utilization of ACGD waste.