精油 冻点的测定

[中文适用范围]： 该测定包括对精油进行缓慢且渐进的冷却，并观察精油从液态转变为固态时的温度变化。 用于测定冰点的装置由容量约500ml的广口容器组成，该容器配有钻孔软木塞或橡胶塞，其中插入粗壁试管。 另一个较小的试管通过另一个钻孔的软木塞或橡胶塞安装到粗壁试管中。 将温度计插入较小的试管中。 [外文原描述]： The determination consists in slow and progressive cooling of the essential oil and observation of the variations in temperature as the oil passes from the liquid to the solid state. The apparatur for determination of freezing point consists of a wide-mouthed container of about 500 ml capacity, provided with a bored cork or rubber stopper into which a stout-walled test tube is inserted. Another smaller test tube is fitted into the stout-walled test tube by means of another bored cork or rubber stopper. Into the smaller test tube a thermometer is inserted.