Ashraf-Khorassini Mehdi, Coleman William M, Umstead Weston J
Department of Chemistry, Virginia Tech, Blacksburg, Virginia, USA.
iiiconsulting, LLC, Conway, South Carolina, USA.
Chirality. 2025 Feb;37(2):e70020. doi: 10.1002/chir.70020.
The influence of additives and modifiers on the chiral HPLC separation of the nicotine enantiomers using UV/Vis detection is discussed. Selected alcohols as modifiers and selected amines as additives were found to have a significant effect on the resolution and retention times of nicotine enantiomers even to the point of eliminating component elution. Systematic variations in the concentration of ethanol, methanol, and isopropanol, as modifiers, along with variations in the concentration of diethylamine, triethylamine, tributylamine, ethylenediamine, isopropylamine, as additives, revealed that the average resolution (R) of the nicotine enantiomers ranged from 2.9 to 7.57, using a mobile phase flow rate of 0.80 mL/min. The average retention times of the nicotine enantiomer pairs ranged from 7.64 and 8.34 min to 13.47 and 14.97 min, with the S(-) enantiomer eluting first. As expected, faster flow rates of 1.0 mL/min reduced retention times by approximately 1-2 min, with a slight decrease in the R values. The %RSD values for both resolution and retention times consistently remained below 2%. The detection limits for the enantiomers were approximately 5 μg/mL. The optimized method successfully detected one part in 100 for the minor R(+) enantiomer in the presence of the dominate S(-) enantiomer and adhered to all established QuEChERS method protocols.
讨论了添加剂和改性剂对使用紫外/可见检测的尼古丁对映体手性高效液相色谱分离的影响。发现选定的醇类作为改性剂和选定的胺类作为添加剂对尼古丁对映体的分离度和保留时间有显著影响，甚至能消除组分洗脱。作为改性剂的乙醇、甲醇和异丙醇浓度的系统变化，以及作为添加剂的二乙胺、三乙胺、三丁胺、乙二胺、异丙胺浓度的变化表明，使用0.80 mL/min的流动相流速时，尼古丁对映体的平均分离度（R）在2.9至7.57之间。尼古丁对映体对的平均保留时间在7.64和8.34分钟至13.47和14.97分钟之间，S(-)对映体先洗脱。正如预期的那样，1.0 mL/min的更快流速使保留时间减少了约1-2分钟，R值略有下降。分离度和保留时间的%RSD值始终保持在2%以下。对映体的检测限约为5 μg/mL。该优化方法成功地在主要的S(-)对映体存在的情况下检测到了痕量R(+)对映体中的万分之一，并且符合所有既定的QuEChERS方法规程。
