ISO 13884:2003规定了一种准确测定反式异构体水平大于或等于5%的天然或加工长链脂肪酸、脂肪酸酯和甘油三酯中分离的反式键的方法。 该方法不适用于或仅在有特定预防措施的情况下适用于含有高水平(超过5%)共轭不饱和度的脂肪和油(例如桐油)；含有改变反式双键周围C-H变形强度的官能团的材料[例如含有蓖麻油酸或其几何异构体蓖麻油酸(12-羟基-9-十八碳烯酸)]；具有长链和短链部分的混合甘油三酯(如二乙酰硬脂)；或一般而言，含有具有官能团的组分的任何材料，所述官能团在或足够接近所述分离的反式双键的C-H变形的966cm-1带处产生特定吸收带，从而干扰所述分离的反式双键的C-H变形的966cm-1带。

ISO 13884:2003 specifies a method for the accurate determination of isolated trans bonds in natural or processed long-chain fatty acids, fatty acid esters and triglycerides with trans isomer levels greater than or equal to 5 %. The method is not applicable, or is applicable only with specific precautions, to fats and oils containing high levels (over 5 %) of conjugated unsaturation (e.g. tung oil); materials containing functional groups which modify the intensity of the C-H deformation about the trans double bond [e.g. castor oil containing ricinoleic acid or its geometrical isomer, ricinelaidic acid (12-hydroxy-9-octadecenoic acid)]; mixed triglycerides having long- and short-chain moieties (such as diacetostearin); or in general, any materials containing constituents which have functional groups which give rise to specific absorption bands at or sufficiently close to interfere with the 966 cm-¹ band of the C-H deformation of the isolated trans double bond.