氢核磁共振法测定生物柴油中甲醇和乙醇残留量

IF 0.5 4区化学 Q4 CHEMISTRY, MULTIDISCIPLINARY

Quimica Nova Pub Date : 2023-10-09 DOI:10.21577/0100-4042.20230046

Samuel Santos, Cassiane Dutra, Luiz Fontoura

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引用次数: 0

摘要

生物柴油中的酒精残留物即使经过提纯步骤也可能存在。它降低了闪点、润滑性和十六烷值。定量生物柴油中残醇的标准技术是顶空取样FID-GC。核磁共振虽然在定量分析中使用不足，但不需要特殊的样品制备，并且消耗的溶剂量小。本研究建立并验证了在9.4 T (400 MHz)谱仪中标准添加1H-NMR测定大豆生物柴油中残留甲醇和乙醇含量的方法。定量限分别为0.07%和0.08%，比可接受的最大限量0.2%低2倍以上。准确度和精密度被认为适合于酒精含量在规范限度附近。

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DETERMINATION OF RESIDUAL METHANOL AND ETHANOL IN BIODIESEL BY 1H-NMR

Alcohol residues in biodiesel can be present even after the purification steps. It diminishes the flash point, lubricity and cetane number. The standard technique to quantify residual alcohol in biodiesel is the FID-GC with headspace sampling. NMR, although underused for quantitative analyses, requires no special sample preparation, and consumes low volume of solvent. In this work, methodologies for the residual methanol and ethanol contents in soy biodiesel by 1H-NMR in a 9.4 T (400 MHz) spectrometer by standard addition were developed and validated. Quantification limits were found equal to 0.07 and 0.08% respectively, so more than twice lower than the maximum level acceptable, which is 0.2%. Accuracy and precision were considered suitable for the alcohol content around the specification limit.

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来源期刊

Quimica Nova 化学-化学综合

CiteScore

1.60

自引率

12.50%

发文量

审稿时长

2-4 weeks

期刊介绍： Química Nova publishes in portuguese, spanish and english, original research articles, revisions, technical notes and articles about education in chemistry. All the manuscripts submitted to QN are evaluated by, at least, two reviewers (from Brazil and abroad) of recognized expertise in the field of chemistry involved in the manuscript. The Editorial Council can be eventually asked to review manuscripts. Editors are responsible for the final edition of QN.