Abstract Biodiesels produced from commercial and non-traditional feedstocks were analyzed by ASTM D6584-17 for monoglyceride (monoacylglycerol, or MG) content. It was found that D6584-17 as currently written may not accurately determine MGs from conventional feedstocks due to significant differences in retention time using modern instrumentation. For biodiesel from non-traditional feedstocks, D6584-17 did not sufficiently account for MGs containing fatty acids outside of C16 and C18 species. This led to under- and over-reporting of MGs, as critical components were not accurately measured. Improvements to the method were made through a three-step process. First, a standard mixture of MGs was run to determine the retention time of individual MGs that could be present in the samples from C10 to C24. An additional analysis for the fatty acid methyl ester (FAME) profile was used to determine the major MG species present in the biodiesel samples, using the assumption that the MG profile was proportional to the FAME profile. The biodiesel samples were analyzed by D6584-17, and the MGs were identified using retention time matching, based on the major species expected from measuring the FAME profile. By combining these two methods, the accuracy of MG determination by D6584-17 was improved for biodiesels prepared from all feedstocks.

中文翻译：

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通过 ASTM 方法 D6584-17 改进生物柴油单甘油酯的测定

摘要 通过 ASTM D6584-17 分析了由商业和非传统原料生产的生物柴油的单酸甘油酯（单酰基甘油，或 MG）含量。发现目前编写的 D6584-17 可能无法准确确定来自常规原料的 MG，因为使用现代仪器的保留时间存在显着差异。对于来自非传统原料的生物柴油，D6584-17 没有充分考虑包含 C16 和 C18 物种之外的脂肪酸的 MG。这导致 MG 报告不足和过度报告，因为关键组件没有得到准确测量。通过三步过程对该方法进行了改进。首先，运行 MG 的标准混合物以确定从 C10 到 C24 的样品中可能存在的单个 MG 的保留时间。对脂肪酸甲酯 (FAME) 曲线的附加分析用于确定生物柴油样品中存在的主要 MG 种类，假设 MG 曲线与 FAME 曲线成正比。生物柴油样品通过 D6584-17 进行分析，并基于通过测量 FAME 曲线预期的主要物种，使用保留时间匹配来识别 MG。通过将这两种方法结合起来，D6584-17 对所有原料制备的生物柴油的 MG 测定准确度有所提高。基于测量 FAME 谱所预期的主要物种。通过将这两种方法结合起来，D6584-17 对所有原料制备的生物柴油的 MG 测定准确度有所提高。基于测量 FAME 谱所预期的主要物种。通过将这两种方法结合起来，D6584-17 对所有原料制备的生物柴油的 MG 测定准确度有所提高。