Niu Jiajia, He Aimin, Gao Feng, Yu Zhenhua, Li Jiehui, Liu Yang, Hao Hongling, Chen Jingzheng, Zhang Fengmei, Chen Chen, Yue Liqing
Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, China.
China Tobacco Hebei Industrial Co., Ltd, Shijiazhuang, 050051, China.
BMC Chem. 2025 Jul 2;19(1):186. doi: 10.1186/s13065-025-01556-5.
It is important to accurately test the content of the main components (i.e., oxyacetyl, vinyl, and vinyl alcohol) of VAE-type adhesives/emulsions. In this study, we first investigated the solubility of dried VAE samples. Dimethyl sulfoxide (DMSO) was the best solvent tested, and at a sample concentration of 10,000 µg/mL, complete dissolution was achieved after 3 h of ultrasonication. Second, different chemical shifts of protons in the H NMR spectrum of VAE samples were assigned as follows: 2.01 ppm for CH of oxyacetyl groups, 1.5-1.8 ppm for the backbone CH connected to vinyl alcohol or oxyacetyl groups, and 1.2 ppm for the backbone CH. Based on these assignments, an H NMR normalization-based quantification method was established. Meanwhile, correction factors of each VAE functional group relative to the internal standard benzyl benzoate were calculated to establish an H NMR internal standard-based quantification method. For the vinyl acetate monomer that was tested as a proxy for the oxyacetyl group, the H NMR internal standard-based quantification method yielded a closer result (37.44%) to the classical method (37.30%) than the normalization-based method. The method exhibited good repeatability and reproducibility (repeatability RSD < 5%, reproducibility RSD: vinyl and oxyacetyl < 5%, vinyl alcohol < 11.24%). In contrast, a C NMR internal standard-based quantification method was deemed unsuitable for the quantitative analysis of VAE main components due to its high sample concentration requirements, lengthy test durations, and tendency to underestimate the actual contents. Finally, a H NMR internal standard-based quantification method was established for the determination of the main components of VAE-type adhesives/emulsions.
准确测试VAE型胶粘剂/乳液的主要成分（即乙酰氧基、乙烯基和乙烯醇）含量非常重要。在本研究中，我们首先研究了干燥VAE样品的溶解性。二甲基亚砜（DMSO）是测试的最佳溶剂，在样品浓度为10000 µg/mL时，超声处理3小时后可完全溶解。其次，VAE样品的氢核磁共振谱（H NMR）中质子的不同化学位移归属如下：乙酰氧基的CH为2.01 ppm，与乙烯醇或乙酰氧基相连的主链CH为1.5 - 1.8 ppm，主链CH为1.2 ppm。基于这些归属，建立了一种基于H NMR归一化的定量方法。同时，计算了每个VAE官能团相对于内标苯甲酸苄酯的校正因子，以建立基于H NMR内标的定量方法。对于作为乙酰氧基替代物测试的醋酸乙烯酯单体，基于H NMR内标的定量方法得到的结果（37.44%）比基于归一化的方法更接近经典方法（37.30%）。该方法具有良好的重复性和再现性（重复性相对标准偏差RSD＜5%，再现性RSD：乙烯基和乙酰氧基＜5%，乙烯醇＜11.24%）。相比之下，基于碳核磁共振（C NMR）内标的定量方法由于其对样品浓度要求高、测试时间长以及倾向于低估实际含量，被认为不适用于VAE主要成分的定量分析。最后，建立了一种基于H NMR内标的定量方法用于测定VAE型胶粘剂/乳液的主要成分。
