Based on previously reported chiral separation of free amino-acids (AAs) using packed-column supercritical fluid chromatography (pSFC), it was desirable to investigate parameters influencing the response of evaporative light scattering detector (ELSD). The effect of several parameters, such as SFC conditions (outlet pressure, temperature and flow rate) and ELSD settings (drift tube temperature of nebulisation and nebulizer gas pressure) on the sensitivity (response) of ELSD have been studied. Based on optimization an outlet pressure of 170 bar, a temperature of 40 °C and a flow rate of 3 mL/min were chosen, and a drift tube temperature of 60 °C and a nebulizer gas pressure of 3.0 bar were found to be optimal. Limits of detection (LOD) and limits of quantification (LOQ) were determined for studied amino acids (AAs) and were found to be lower than values determined without optimization. The enantiomeric elution order was also determined for leucine, phenylalanine, isoleucine, valine, carnitine and histidine by the injection of the L-AAs in the above-mentioned optimized conditions. The L-enantiomers eluted first for four out of the six AAs studied. Conclusions on the influence of the screened variables on ELSD sensitivity and recommendations for AAs analytical studies in SFC are given.

中文翻译：

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手性超临界流体色谱中蒸发光散射检测器检测天然氨基酸的优化

基于先前报道的使用填充柱超临界流体色谱 (pSFC) 对游离氨基酸 (AA) 进行手性分离，需要研究影响蒸发光散射检测器 (ELSD) 响应的参数。已经研究了几个参数，例如 SFC 条件（出口压力、温度和流速）和 ELSD 设置（雾化的漂移管温度和雾化器气体压力）对 ELSD 的灵敏度（响应）的影响。在优化的基础上，选择出口压力 170 bar、温度 40 °C 和流速 3 mL/min，并发现漂移管温度 60 °C 和雾化器气压 3.0 bar 是最佳的. 确定了研究氨基酸 (AA) 的检测限 (LOD) 和定量限 (LOQ)，发现它们低于未经优化确定的值。通过在上述优化条件下注射 L-AA，还确定了亮氨酸、苯丙氨酸、异亮氨酸、缬氨酸、肉碱和组氨酸的对映体洗脱顺序。在所研究的六种 AA 中，L-对映异构体首先被洗脱出来。给出了筛选变量对 ELSD 灵敏度的影响的结论以及对 SFC 中 AA 分析研究的建议。在所研究的六种 AA 中，L-对映异构体首先被洗脱出来。给出了筛选变量对 ELSD 灵敏度的影响的结论以及对 SFC 中 AA 分析研究的建议。在所研究的六种 AA 中，L-对映异构体首先被洗脱出来。给出了筛选变量对 ELSD 灵敏度的影响的结论以及对 SFC 中 AA 分析研究的建议。