Ethyl acetate potentially contains formaldehyde and acetaldehyde as impurities. Ephedrines (ephedrine and pseudoephedrine) react with these aldehydes to give oxazolidines. The purpose of this study is to elucidate the effects of aldehydes in ethyl acetate on the analysis of ephedrines by gas chromatography/mass spectrometry (GC/MS). Ephedrines dissolved in a basic solution were extracted with five lots of ethyl acetate; then, injected into a GC/MS system. Acetaldehyde in ethyl acetate was determined by headspace GC/MS. Acetaldehyde-free ethyl acetate, prepared by washing with sodium bisulfite solution, was also subjected to ephedrine extraction and acetaldehyde determination. Four of the five ethyl acetate lots produced 3,4-dimethyl-5-phenyloxazolidines (formaldehyde adducts of ephedrines) and 2,3,4-trimethyl-5-phenyloxazolidines (acetaldehyde adducts of ephedrines). Acetaldehyde was detected in the range of 23–89 μL/L in four lots of ethyl acetate and not detected in one lot, and the detection of acetaldehyde was associated with oxazolidine formation. Washing with sodium bisulfite solution removed ~90% of acetaldehyde and prevented oxazolidine formation. The study indicated that ephedrines reacted with aldehydes in ethyl acetate to produce oxazolidines and washing with sodium bisulfite solution prevented it. It is necessary to exercise caution when using ethyl acetate to extract ephedrines.

中文翻译：

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与乙酸乙酯中的麻黄碱和醛类杂质反应生成恶唑烷衍生物

乙酸乙酯可能含有甲醛和乙醛作为杂质。麻黄碱（麻黄碱和伪麻黄碱）与这些醛反应生成恶唑烷。本研究的目的是阐明乙酸乙酯中的醛类对通过气相色谱/质谱 (GC/MS) 分析麻黄碱的影响。用五批乙酸乙酯萃取溶解在碱性溶液中的麻黄碱；然后，注入GC/MS 系统，用顶空GC/MS 测定乙酸乙酯中的乙醛。无乙醛乙酸乙酯，用亚硫酸氢钠溶液洗涤制得，经麻黄碱萃取和乙醛测定。五批乙酸乙酯中有四批生产了 3,4-二甲基-5-苯恶唑烷（麻黄碱的甲醛加合物）和 2,3，4-三甲基-5-苯恶唑烷（麻黄碱的乙醛加合物）。乙醛在 4 批乙酸乙酯中检出 23-89 μL/L，1 批未检出，乙醛的检出与恶唑烷形成有关。用亚硫酸氢钠溶液洗涤除去约 90% 的乙醛并防止恶唑烷形成。研究表明，麻黄碱在乙酸乙酯中与醛类反应生成恶唑烷，用亚硫酸氢钠溶液洗涤可防止它发生。使用乙酸乙酯提取麻黄碱时必须谨慎。用亚硫酸氢钠溶液洗涤除去约 90% 的乙醛并防止恶唑烷形成。研究表明，麻黄碱在乙酸乙酯中与醛类反应生成恶唑烷，用亚硫酸氢钠溶液洗涤可防止它发生。使用乙酸乙酯提取麻黄碱时必须谨慎。用亚硫酸氢钠溶液洗涤除去约 90% 的乙醛并防止恶唑烷形成。研究表明，麻黄碱在乙酸乙酯中与醛类反应生成恶唑烷，用亚硫酸氢钠溶液洗涤可防止它发生。使用乙酸乙酯提取麻黄碱时必须谨慎。