KINETIC OPTIMIZATION OF STRAIGHT OPEN-TUBULAR LIQUID-CHROMATOGRAPHY
KINETIC OPTIMIZATION OF STRAIGHT OPEN-TUBULAR LIQUID-CHROMATOGRAPHY
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DOI：
10.1016/s0021-9673(00)95263-4
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发表时间：
1979-01-01
期刊：
影响因子：
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通讯作者：
GILBERT, MT
中科院分区：
文献类型：
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作者：
KNOX, JH;GILBERT, MT
按照Knox和Saleem对填充柱的处理方法对开管柱的液相色谱进行理论分析表明，对于给定的压降、板数、溶质和洗脱液，开管柱的最佳直径约为最佳填充柱中颗粒直径的五分之一，分析时间约少100倍。然而，计算出的毛细血管孔对于小于或接近最小孔径的操作来说是不切实际的，因为所需的理论板数n超过了几百万。毛细管液相色谱的实际限制无疑是由检测器产生的分散引起的。在此基础上，导出了以未保留溶质的标准差、σ°v和压降为限制条件的毛细管液相色谱的最佳条件。结果表明，在这些约束条件下，最优柱孔与n无关，而分析时间随n的增加而直接增加。将这种方式限制的毛细管柱与填充型高效液相色谱柱在最小条件下的性能进行比较，结果表明，当σ°v0.1 mm3时，需要30 μm孔径的毛细管，且当n > 300,000时，毛细管柱的性能优于填充柱。然而，当σ°v0.001 mm3时，则需要10 μm孔径的毛细管，并且当> 30,000时比填充柱更快。例如，n106峰的时间tm在毛细管中为2小时，而在填充柱中为55小时。根据Golay方程对已发表的实验数据进行了检验，结果表明，对于未保留的溶质和保留的溶质，一致性都非常好。因此，如果检测器体积确实可以减少到0.001 mm3左右，那么毛细管高效液相色谱的应用前景很好。
A theoretical analysis of liquid chromatography in open-tubular columns along the lines of the treatment given by Knox and Saleem for packed columns indicates that for a given pressure drop, plate number, solute and eluent, the optimal diameter of the open tubular column is about one fifth of the diameter of the particles in the optimal packed column and the analysis time is about 100 times less. However, the calculated bores of capillaries are impracticably small for operation oat or near the minimum inhunlessN, the number of theoretical plates required, exceeds several million. The practical limitation to capillary liquid chromatography undoubtedly arises from the dispersion produced by the detector. Accordingly, optimal conditions are derived for capillary LC in which the standard deviation of the unretained solute, σ°v, and pressure drop are taken as limiting conditions. It is shown that with these constraints the optimal column bore is independent ofNwhile the analysis time increases directly withN.Comparison of the performance of capillary columns limited in this way, with packed high-performance liquid chromatographic (HPLC) columns operated under conditions of minimumh, shows that if σ°v 0.1 mm3then capillaries of 30 μm bore are required and will give better performance than packed columns only ifN> 300,000. However, if σ°v 0.001 mm3then capillaries of 10 μm bore are required and are faster than packed columns wheN> 30,000. For example, the time,tm, for a peak ofN 106is 2 h with the capillary compared with 55 h with the packed column.Published experimental data are examined in the light of the Golay equation and the agreement is shown to be excellent for both unretained and retained solutes. It is concluded that if detector volumes can indeed be reduced to around 0.001 mm3there are excellent prospects for capillary HPLC.