问题 单项选择题 B型题

加入絮凝剂使高分子杂质沉降()

A.水提醇沉法

B.离心分离法

C.大孔树脂法

D.膜分离法

E.吸附澄清法

答案

参考答案:E

解析:

本组题目考查了中药的常用分离方法和常用精制方法。常用的分离方法有:水提醇沉法、吸附澄清法、大孔吸附树脂吸附法和膜分离法。水提醇沉法是在水提浓缩液中加入乙醇使达不同含醇量,低分子有效成分仍溶于醇液中,而高分子杂质沉淀析出。膜分离法指以细微孔径的薄膜为滤过介质,使药液中成分得以分离而精制。故108题答案选D。吸附澄清法是指水提浓缩液加入絮凝剂使高分子杂质絮凝沉淀被去除。常用絮凝剂有名胶、琼脂、蛋青、硫酸铝。故109题答案选E。壳聚糖的沉淀原理是:壳聚糖带正电与药液中带负电的杂质交联而沉淀。故110题答案选E。大孔吸附树脂吸附法指将经过预处理的中药提取液通过大孔吸附树脂,使成分被吸附后,先以水或低浓度乙醇洗脱盐、小分子糖等杂质,再以适宜浓度乙醇洗脱有效成分。常用的分离方法有沉降分离法、离心分离法、滤过分离法。沉降分离法是指固体微粒依据本身重力在液体介质中自然下沉使之与液体分离的方法。离心分离是指通过离心分离位料液中固体与液体或两种不相混溶的液体产生大小不同的离心力而达到分离的方法。故111题答案选B。滤过分离法将混悬液通过多孔的介质,使固体微粒被截留,液体经介质孔道流出,达到固液分离的方法。

阅读理解

Mike found a job in a bookstore after he finished middle school. He wouldn’t do anything but wanted to get rich.

It was a cold morning. It snowed and there was thin ice on the streets. Few people went to buy books and the young man had nothing to do. He hated to read, so he watched the traffic. Suddenly he saw a bag fall off a truck and it landed by the other side of the street.

“It is full of expensive things.” Mike said to himself. “I have to get it right now, or others will take it away.”

He went out of the bookstore and ran across the street. A driver saw him and began to whistle (鸣笛), but he didn’t hear it and went on running. The man drove to the side, hit a big tree and hurt himself in the accident. Two weeks later, Mike was taken to the court (法庭). A judge asked if he heard the whistle when he was running across the street. He said that something was wrong with his ears and he could hear nothing.

“But you heard me this time,” said the judge.

“Oh, I’m sorry. Now I can hear with one ear.”

“Cover (盖住) the ear with your hand and listen to me with your deaf (聋的) one. Well, can you hear me?”

“No, I can’t , sir.”

“You told a lie. There is nothing wrong with either of your ears,” the judge said.

小题1:Mike found a job as a _____________ when he left school.

A.driver

B.judge

C.policeman

D.bookseller小题2:One day he saw __________ in the street.

A.an accident

B.a thief

C.a lost bag

D.a lot of money小题3:The traffic accident happened because _____________.

A.Mike was running to the street

B.the driver was deaf and couldn’t hear anything

C.the car hit the bag in the middle of the street

D.the driver wanted to pick up the bag小题4:Which of the following statements is NOT true?

A.Mike didn’t do well in his work.

B.The judge believed Mike’s words.

C.Mike told a lie.

D.The car hit a tree beside the street.

问答题 简答题