小中大液液萃取，怎样除掉二氯甲烷
各位老师，新手求助。我正要做苯丁酸钠杂质C气相方法，参考EP上的方法，方法如下：
Impurity C. Gas chromatography (2.2.28).
Silylation solution. To 2 mL of N,O-bis(trimethylsilyl)tri-
fluoroacetamide R add 0.04 mL of chlorotrimethylsilane R
and mix.
Test solution.Dissolve50.0mgofthesubstancetobeexamined
in 3 mL of water R and add 0.5 mL of hydrochloric acid R.
Extract with 2 quantities, each of 5 mL, of methylenechlorideR.
Evaporate the combined methylene chloride extracts to dryness
in a vial with a screw cap and add 0.5 mL of the silylation
solution.Sealthevialandheatat70±5°Cfor20min.
杂质C（4-cyclohexylbutanoic acid.）
我们买到一个提纯品（>98%），常温下是液体,我在网上查不到沸点。但EP药典上样品溶液是用5ml二氯甲烷萃取2次，于带螺丝帽玻璃容瓶中蒸干萃取物中残留的二氯甲烷。实验我还没做，我有很多疑问，用什么蒸干？会不会连带杂质C也一起蒸掉？温度多少合适？都是液态的，怎样确定萃取物中残留的二氯甲烷已完全蒸干？还请各位老师帮帮忙，小弟我是个新手。
