Thermal lens-circular dichroism detector for high-performance liquid chromatography.
Thermal lens-circular dichroism detector for high-performance liquid chromatography.
复制标题
用于高效液相色谱的热透镜圆二色性检测器。
DOI：
10.1021/ac00221a011
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发表时间：
1990
影响因子：
7.4
通讯作者：
Tran,CD
中科院分区：
文献类型：
--
作者：
Xu,MR;Tran,CD
研制了一种新型的高灵敏度高效液相色谱手性检测器。该探测器是基于利用热透镜效应测量手性流出物的圆二色性。在该仪器中，色谱流出物依次被左旋圆偏振激光（LCPL）和右旋圆偏振激光（RCPL）激发，这两种激发光都来自同一个氩离子激光器，其线偏振输出通过普克尔斯盒转换为圆偏振输出。用探测激光束与两束激发光近准直的方法测量了LCPL和RCPL样品吸收后产生的热。锁定放大器用于测量热透镜圆二色性（TL-CD）信号，该信号对应于由LCPL和RCPL激发光束产生的热透镜信号的差异。该TL-CD手性检测器除了具有高灵敏度外，还具有真实的实时提供手性样品的手性（即圆二色性）和光学纯度信息的能力。用反相离子对色谱法将（-）-三（乙二胺）钴（Ⅲ）（k ′ = 0.45）和（+）-三（乙二胺）钴（Ⅲ）（k ′ = 1.40）从相应的外消旋混合物中分离出来，检测限分别为7.2ng。该检测限是通过使用10-mL流动池和具有5-mm路径长度和6-mW激发激光束（λ = 514.5 nm）调制在2 Hz.手性药物的分析已日益成为科学和技术中的重要课题。流行或更确切地说需求是基于这样的事实，即在目前全世界销售的1327种完全合成的药物中，528种是手性的并且能够作为两种或多种光学异构体存在。通常，只有一种形式的对映异构体是手性的。另一种或多种可逆转或以其他方式限制所需对映体的作用。然而，在528种手性合成药物中，只有61种以单一对映体形式销售，而其他467种则以外消旋体形式销售。因此，制药工业需要有效的分析和制备分离方法来分离各种对映体化合物（1）也就不足为奇了。液相色谱法（LC）似乎是首选的仪器，因为它的效率，速度，广泛的适用性和再现性。在过去的几年中，已经提出了各种方法来使用LC将外消旋混合物光学拆分成对映异构体。也许最值得注意的是基于环糊精固体固定相的使用。
A novel and ultrasensitive chiral detector for high-performance liquid chromatography has been developed. This detector Is based on the measurement of circular dichroism of chiral effluents by the thermal lens effect. In this Instrument, the chromatographic effluent was sequentially excited by left circularly polarized laser light (LCPL) and right circularly po-larized laser light (RCPL); both of these excitation beams were derived from the same argon Ion laser whose linearly polarized output was transformed Into circularly polarized Bght by means of a Pockels cell. The heat generated as a con-sequence of the sample absorption of the LCPL and RCPL was measured by the probe laser beam colllnearly overlap-ping with the two excitation beams. A lock-in amplifier was used to measure the thermal lens-circular dichroism (TL-CD) signal which corresponds to the difference in the thermal lens signals produced by the LCPL and RCPL excitation beams. In addition to Its high sensitivity, the advantages of this TL-CD chiral detector IncludeIts ability to provide, directly and In real time, Information on the chirality (le, circular dichroism) and optical purity of chiral samples. A detection limit of 7.2 ng was achieved for (-)-trte (ethylenedlamlne) co-balt (III)(*'= 0.45) as well as for the (+)-trls (ethylenedl-amlne) cobalt (III)(k'= 1.40) when these two enantiomers were chromatographIcally separated from the corresponding racemic mixture through the use of bls (pd-tartrato) dl-antknonate (III) Ion pair reversed-phase chromatography. This limit of detection was found by using a 10-mL flow cell and having 5-mm path length and 6-mW excitation laser beam (X= 514.5 nm) modulated at 2 Hz.The analysis of chiral drugs has increasingly become an important subject in science as well as in technology. The popularity or rather demand is based on the fact that of 1327 totally synthetic drugs which are currently marketed worldwide, 528 are chiral and capable of existing as two or more optical isomers. Very often, only one form óf enantiomers is pharmacologically active. The other or others can reverse or otherwise limit the effect of the desired enantiomer. However, only 61 of the 528 chiral synthetic drugs are marketed as single enantiomers, while the other 467 are sold as racemates. It is thus hardly surprising that the pharmaceuticalindustry needs effective analytical and preparative separation methods for a variety of enantiomericcompounds (1). Liquid chromatography (LC) seems to be the instrument of choice because of its efficiency, speed, wide applicability, and reproducibility. Various approaches have been made in the last few years to use the LC for optical resolution of racemic mixtures into enantiomers. Perhaps the most notable one is based on the use of cyclodextrinsolid stationary phase.