ISO 16931:2009规定了一种使用高效排阻色谱法（HPSEC）测定油和脂肪中聚合三酰甘油（PTAG）质量分数的方法，其中至少含有3%（来自峰面积）这些聚合物。PTAG（严格地说是二聚和低聚三酰甘油）是在脂肪和油加热过程中形成的，因此，该方法用于评估使用后煎炸脂肪的热劣化。 该方法适用于油炸脂肪和经过热处理的脂肪和油，前提是PTAG的含量至少为3%。它也可用于测定动物饲料脂肪中的聚合物，尽管在这种情况下，使用的提取方法可能会影响结果。

ISO 16931:2009 specifies a method using high-performance size-exclusion chromatography (HPSEC) to determine the contents, as mass fractions, of polymerized triacylglycerols (PTAGs) in oils and fats which contain at least 3 % (from peak areas) of these polymers. PTAGs (strictly speaking dimeric and oligomeric triacylglycerols) are formed during the heating of fats and oils, and thus, the method serves to assess the thermal deterioration of frying fats after use. This method is applicable to frying fats and fats and oils that have been thermally treated, provided that the content of PTAGs is at least 3 %. It can also be applied to the determination of polymers in fats for animal feedstuffs, although in this case, the extraction method used can have an influence on the result.