问题 单项选择题 B型题

正相分配色谱的固定相为()

A.缓冲溶液

B.丁醇

C.乙酸乙酯

D.甲醇

E.石蜡油

答案

参考答案:A

解析:

本组题目考查了正相、反相分配色谱法的固定相。分配柱色谱是将两相溶剂中的一相涂覆在硅胶、硅藻土、纤维素粉等多孔载体上,作为固定相,填充在色谱管中,然后加入与固定相不相混溶的另一相溶剂(流动相)冲洗柱色谱;这样,物质在两相溶剂中相对作逆流移动,在移动过程中不断进行动态分配而得分离。正相色谱采用强极性溶剂作为固定相,如水、缓冲溶液;而用弱极性溶剂作为流动相,如氯仿、乙酸乙酯、丁醇等。正相色谱法常用于分离水溶性或极性较大的成分,如苷类、糖类等化合物。故109题答案选A。反相色谱可用弱极性溶剂作为固定相,如石蜡油;而用强极性溶剂作为流动相。反相色谱法常用于分离脂溶性化合物,如高级脂肪酸、油脂、游离甾体等。故110题答案选E。

单项选择题
阅读理解

Along the seashore(海边),the tall coconut(椰子)trees waved in he wind. The sand was white in the bright sun, and the ocean was dark blue. The houses in the town near the shore, were painted white. The boats had been pulled up on the shore. Usually they would all be in the water with hard-working fishermen. But today was a holiday, and everyone was  preparing for the celebration that was going to take place that evening.

In the distance, men could be seen climbing the coconut trees. They were singing as they worked. There were monkeys in the trees, too. The monkeys were jumping up and down and screaming angrily.The climbers just laughed at the monkeys and continued to pick the fruits.

小题1:What is this passage about?

A.It tells us a story of the monkeys.

B.It describes the scene on the seashore.

C.It talks about the life of the fishermen.

D.It is about how the people celebrated a holiday.小题2:The boats had been pulled up on the shore because_________.

A.it was a holiday

B.the weather was too hot

C.there was going to be a storm

D.it was not the season for fishing小题3:The men climbed the coconut trees to_________.

A.pick the coconuts

B.catch the monkeys

C.look at the ocean far away

D.see who could climb high and fast小题4:The word "screaming" in Paragraph Two probably means _______.

A.singing and working

B.jumping up and down

C.running here and there

D.shouting in a high voice小题5:The monkeys were angry because________.

A.the men were trying to catch them

B.the men wanted to drive them away

C.the men got the coconuts , which were their food

D.the men climbed higher and faster than they did