问题
单项选择题 A1型题
用柱色谱分离有邻二酚羟基或3-OH或5-OH的黄酮类化合物时，不适合的填充剂是（）
A.聚酰胺
B.大孔吸附树脂
C.葡聚糖凝胶
D.硅胶
E.氧化铝
答案
参考答案：E
解析：有3-羟基或5-羟基、4-羰基及邻二酚羟基结构的黄酮类化合物与铝离子络合而被牢固地吸附在氧化铝柱上，难以洗脱，所以不适合应用。其他四种填充剂都可以选用。
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用柱色谱分离有邻二酚羟基或3-OH或5-OH的黄酮类化合物时，不适合的填充剂是（）
A.聚酰胺
B.大孔吸附树脂
C.葡聚糖凝胶
D.硅胶
E.氧化铝
参考答案：E
解析：有3-羟基或5-羟基、4-羰基及邻二酚羟基结构的黄酮类化合物与铝离子络合而被牢固地吸附在氧化铝柱上，难以洗脱，所以不适合应用。其他四种填充剂都可以选用。
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| It rained in the country those days. It was very 1 everywhere. Classes in the morning were over and the children of about 5 to 6 years old 2 around Mrs. Brown, the teacher, and waited. Five minutes later she finished putting the 36th boot on the 3 pair of little feet. All the children left except (除了)the smallest one. Now she had a look at her 4 , it was five past twelve. Her daughter was waiting for her at the school gate. She said she was going to take her to a 5 at noon, the little girl came to school without breakfast. 6 she was anxious (焦急的)to finish the last pair. They were for little Johnny Smith, a quiet boy. Mrs. Brown had a very 7 time getting his boots on as they were a bit too small for his growing feet, but she finally succeeded (成功). To her dismay (沮丧), little Johnny looked at her 8 and said, "Teacher, these boots aren't mine." In a hurry, but wanting to be 9 Mrs. Brown groaned (呻吟) and took them off. But at that moment Johnny continued,"They 're my little brother 's. Mine are broken and Mummy had no time to 10 them this morning, so she told me to wear them to school today." | ||||
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