Xiaoyu Gong,Tanglong Liu,Shanshan Yu,Yi Meng,Jie Lu,Yi Cheng,Haisong Wang
It is significant to develop low cost, environmental friendly and renewable bio-based adhesives without formaldehyde. In this paper, acetonitrile extracting lignin (AEL) was used as raw material, modified by phenol and mixed with aqueous of polyvinylpyrrolidone (K30), a biocompatible agent, to prepare a high-performance formaldehyde-free lignin-based adhesive. The results of the experiments showed the optimal condition as follows: the mole ratio of lignin to phenol 1:2, the reaction temperature 80 ℃, the reaction time 3 h, the concentration of K30 10%, mole ratio of PAEL to K30 1:0.4, the shear strength of the adhesive reach up to 1.70 MPa (Technical lignin-based adhesive only 0.11 MPa), and it was still as high as 1.02 MPa after soaking in water for 24 h. Compared with the adhesive (1.12 MPa) on the market, the as-prepared sample shows a much higher shear strength, meeting the National Primary Standard of plywood (≥1.0 MPa) and according with national standard.
Ethephon (ETH) is a widely used plant growth regulator in fruit production. Due to its harm to people’s health, its content is an important indicator for fruit quality control. However, due to the extremely high polarity and acidity, as well as the absence of chromophores, efficient and simple detection of ETH remains challenging. In this work, a convenient method for determining trace ETH in fruit was developed that involved a combination of catalytic methylation and gas chromatography-mass spectrometry (GC-MS) analysis. ETH in fruit was extracted with acetonitrile and derivatized with (trimethylsilyl) diazomethane (TMSD) by the catalysis of trimethylchlorosilane to generate methylated ETH (ETH-M) which was determined by GC-MS. The instrumental linear range of ETH was 10–1000 µg/L with a coefficient of determination (R2) > 0.999. The limit of detection (LOD) of the method was 1.0 µg/kg. The ETH content in 12 types of fruits was determined with a reasonable recovery rate ranging from 83.20 ± 0.05% to 118.21 ± 0.01%. The ETH content in the unwashed fruits was in the range of undetectable (ND) to 111 µg/g and below the LOD in their flesh. After washing, the content was significantly reduced and even undetectable. The established method showed good efficiency, selectivity, and reproducibility, and can be used for the determination of ETH in various fruits.
危险品化学品经营许可证（带存储）