1?0.1821?A?B?2C?2?1?由此可得?0.3384?A?B?4C
4?1?0.6536?A?B?8C?8?解得:A=0.0207cm,B=0.0068 cm2/s,C=0.079s
uopt?BC?0.00680.079?0.2934cm/sHmin?A?2B?C?0.0207?20.0068?0.079?0.06706cmHmin0.06706??0.0958时,u?0.1483cm/s,0.70.7H0.06706H?min??0.0745时,u?0.1270cm/s0.90.9H?R1?R2N1N2N12N112
72.在其他相同色谱条件下,若色谱柱的理论塔板数增加一倍,对两相邻色谱的分离度将增加多少倍? 解:
??,即分离度是之前的2倍。
73.在柱长为18cm的高效液相色谱柱上分离组分A和B,其保留时间分别为16.40min和17.63min;色谱峰底宽分别为1.11min和1.21min,死时间为1.30min,试计算:(1)色谱柱的平均理论塔板数N;(2)平均理论塔板高H;(3)两组份的分离度R和分离所需时间;(4)欲实现完全分离,即分离度R=1.5,需柱长和分离时间各多少? 解:(1)
?16.40?2N1?16()?16??.7??3492W11.11???17.63?N2?16()?16????3396.7
W2?1.21?1N平均?(N1?N2)?3444.72L18??5.2?10?3cm (2)H?N3444.72tR12tR22(3)R?2tR2?tR1??W1?W2??2?17.63?16.40???1.1,分离时间即t?1.21?1.11?4tR2?tR1?N?2tR2?tR1R2?17.63min
(4)R?2tR2?tR1???W1?W2??????N?17.63?16.40??0.018N
2?17.63?16.40?当R=1.5时,N=9645;
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k2?k1?t,R2tMt,R1tM??17.63?1.301.3016.40?1.301.30,k2tR217.63?1.30???,??1.08k1tR116.40?1.30R?1.5?N???1??k2???4?????1?k2????????
6945?1.08?1??k2???4?1.08???1?k20.97?0.97k2?k2k2?32.3k2?tR2tR2?1.301.30?43.3?32.374.采用100cm长的色谱柱分离某多组分混合物,流动相流速为90cm/min,色谱柱的理论塔板数为1600,混
,
合物组后洗出组分的k=5,最难分离物质对的α=1.10,试估算:(1)若要求最难分离物质的分离度R=1和1.5,其分离时间各为多少?(2)优化色谱条件,最难分离物质对的α上升为1.25,实现上述分离度的分离时间为多少?(3)其他条件不变,降低流动相流速至60cm/min,其柱效增加到3000理论塔板,实现上述分离度的分离时间为多少? 解:(1)由tR22????k?1?H?16R?可知 ?2uk???1?23当R?1时,tR2100?1.10??5?1??16?12????11.62min??21.10?11600?905??23当R?1.5时,tR2100?1.10??5?1??16?1.52????26.14min??21.10?11600?905??23(2)当??1.25时,R?1时,tR22100?1.25??5?1??16?1?????2.4min?21600?905?1.25?1?23223100?1.25??5?1?当R?1.5时,tR2?16?1.5????5.4min??21600?905?1.25?1?(3)当u?60cm/min,N?3000时,当R?1时,tR2100?1.10??5?1??16?12????1.92min??21.10?13000?605??23
当R?1.5时,tR2100?1.10??5?1??16?1.52????4.32min??21.10?13000?605??2375.从分布平衡研究中,测定溶质M和N在水和正己烷之间的分布平衡常数(K?[M]H2O/[N]hex)分别
34
为6.01和6.20。采用吸附水的硅胶填充柱,以正己烷为流动相分离两组分,已知填充柱的VS/VMwei 0.442,试计算:(1)各组分保留因子。(2)两组分间的选择因子。(3)实现两组分间分离度为1.5需多少理论塔板数?(4)若填充柱的板高H为2.2×10-3cm,需多长色谱柱?(5)如流动相流速为7.10cm/min,洗出两组分需多少时间?
(1)已知:k?KVSV,且S?0.442VMVM所以当K?6.01时,k?6.01?0.442?2.66当K?6.20时,k?6.20?0.442?2.74K6.20(2)??2??1.03K16.01解:
(3)R?N???1??k2???4?????1?k2????
当k?1.5时,1.5?N?1.03?1??2.74?????,所以N?790644?1.03??1?2.74?2(4)L?N?H?79064?2.2?10?3?174cm(5)tR2????16R2????1???k?1?3k2L174?1.03??2.74?1??16?1.52????91.66min??2N?u1.03?179064?7.102.74??2376.用归一化法测定石油C8芳烃馏分中各组分含量,进样分析洗出各组分色谱峰面积和已测定的定量校正因子如
下,试计算各组分含量。 组分 峰面积/mm2 f, 解:
乙苯 180 0.97 对二甲苯 92 1.00 间二甲苯 170 0.96 邻二甲苯 110 0.98 Aifi,wi??100%?Aifi,180?0.97?100%?32.480?0.97?92?1.00?170?0.96?110?0.9892?1.00w对二甲苯??100%?17.11%
180?0.97?92?1.00?170?0.96?110?0.98170?0.96w间二甲苯??100%?30.360?0.97?92?1.00?170?0.96?110?0.98110?0.98w邻二甲苯??100%?20.010?0.97?92?1.00?170?0.96?110?0.98w乙苯?77.已知某试样共含有四个组分,洗出峰面积积分值、已知其定量校正因子如下,计算各组分含量。 组分 峰面积/mm2 f, 1 17312 1.731 2 35731 4.188 3 28453 2.418 4 11174 1.186 35
Aifi,wi??100%?Aifi,17312?1.731?100%?11.45312?1.731?35731?4.188?28453?2.418?11174?1.18635731?4.188?100%?57.19% 解:w2?17312?1.731?35731?4.188?28453?2.418?11174?1.18628453?2.418w3??100%?26.29312?1.731?35731?4.188?28453?2.418?11174?1.18611174?1.186w4??100%?5.06312?1.731?35731?4.188?28453?2.418?11174?1.186w1?78.采用内标法测定天然产物中某两成分A、B的含量,选用化合物S为内标和测定相对定量校正因子标准
物。(1)称取S和纯A,B各180.4mg,188.6mg,234.8mg,用溶剂在25mL容量瓶中配制三元标样混合物,进
‘
样20μL,洗出S,A,B相应色谱峰面积积分值为48964,40784,42784,计算A,B对S的相对定量校正因子f。(2)称取测定试样622.6mg,内标物(S)34.00mg,与(1)相同溶剂、容量瓶、进样量,洗出S,A,B峰面积为32246,46196,65300,计算组分A,B的含量。 解:
‘(1)fi?mi/Aims/As188.6/40784?1.255180.4/48964234.8/42784‘f??1.490B180.4/48964m/Ais34.00/32246'(2)fis?is??0.286ms/As180.4/48964‘fA?
miAifi'mis由wi??100%???100%得'mmAisfis'misAAfA46196?1.25534.00wA???100%???100%?36.56%'m32246?0.286622.6Aisfis'misABfB65300?1.49034.00wB???100%???100%?57.61%'m32246?0.286622.6Aisfis 36