Shake 1.0 g in No．180 powder,with 20 ml chloroform for 15 minutes,filter and reserve the extracted powder for the preparation of solution(2)．Which of the following is not correct in the procedures（）

The physico-chemieal characteristics of rutinis（）A．grad...

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The physico-chemieal characteristics of rutinis（）

To apply this eye medication,wash hands first．To avoid ...

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To apply this eye medication,wash hands first．To avoid contamination,be careful not to touch the dropper or let it touch the affected area．Place the dropper directly over the eye and administer the prescribed number of drops．Look downward and gently close your eyes for 1 to 2 minutes．According to the above,which of the following is not correct（）

The universal colour reagent of the thin-layer chromato...

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The universal colour reagent of the thin-layer chromatography includes（）