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[化学] 【求助】sub分析化学几道 [复制链接]

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发表于 2006-10-31 19:45:15 |显示全部楼层

【求助】sub分析化学几道

1. 关于三种方法的sensitivity比较：
spectrophtometry, photoluminescence,fluorometry,

2.the value for the distribution constant for an organic acid HA between chloroform and water is 102. The dissociation constant of the acid in water is 10-5, and it can be assumed that it does not dissocate or demerit in the chloroform phase. Increasing the PH of the aqueous phase from 4 to 9 has what effect on the fraction of HA extracted into the chloroform phase?

a. the fraction is more than doubled
b.the fraction is increased but is not doubled
c.the fraction is unaffected.
d. the fraction is decreased but is not halved.
e.the fraction is reduced to less than half.

3.cresol red indicator has two color chargers in the ph range 0-14,

ph range    acid color    base color
0.2-1.8       red          yellow
7.2-8.8       yellow       red

what colors are to be expected in solutions at ph of 1.0,6.0,9.0?
1.0       6.0    9.0
a.red       red    yellow
b.red       yellow yellow
c.orange yellow red
d.yellow    orange  red
e.red       red    orange

4. what's the meaning of differential detector in chromatogram?

thanks!

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海底捞月
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发表于 2006-10-31 23:09:44 |显示全部楼层

1 似乎是fluorometry> photoluminescence >spectrophtometry
按响应时间来看的
4 色谱检测器分differential detector（微分检测器）和integral detector(积分检测器两种)，微分检测器是检测瞬时量，如瞬时的浓度或质量，积分检测器是检测一个积累值

2，3题大家都来讨论下吧，不懂啊

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