Department of Pharmaceutical and Biomedical Science, College of Pharmacy, The University of Georgia, Athens, GA 30602-2352, USA.
J Am Soc Mass Spectrom. 2013 Feb;24(2):257-64. doi: 10.1007/s13361-012-0509-5. Epub 2013 Jan 17.
The chemical composition of the solution has a critical impact on the electrospray desorption efficiency of oligonucleotides. Several physiochemical properties of various organic modifiers were investigated with respect to their role in the desorption process of oligonucleotides. The Henry's Law Constant, which reflects the volatility of alkylamines, was found to have a prominent effect on both the electrospray charge state distribution and desorption efficiency of oligonucleotides. Alkylamines with higher k(H,cc)(aq/gas) values such as hexylamine, piperidine, and imidazole reduced the charge state distribution by forming complexes with the oligonucleotide and dissociating from it in the gas phase, while alkylamines with extremely low k(H,cc)(aq/gas) values reduced the electrospray charge state distribution by facilitating ion emission at an earlier stage of the electrospray desorption process. Ion-pairing agents with moderate k(H,cc)(aq/gas) values do not alter the electrospray charge state distribution of oligonucleotides and their ability to enhance oligonucleotide ionization followed the order of decreasing k(H,cc)(aq/gas) values. The Henry's Law Constant also correlated to the impact of the acidic modifiers on oligonucleotide ionization efficiency. Ionization enhancement effects were observed with hexafluoroisopropanol, and this effect was attributed to its low k(H,cc)(aq/gas) and moderate acidity. The comprehensive effects of both alkylamine and hexafluoroisoproapnol on the electrospray ionization desorption of oligonucleotides were also evaluated, and acid-base equilibrium was found to play a critical role in determining these effects.
溶液的化学成分对寡核苷酸的电喷雾解吸效率有至关重要的影响。研究了几种有机溶剂的各种物理化学性质，以探讨它们在寡核苷酸解吸过程中的作用。亨利定律常数（Henry's Law Constant）反映了烷基胺的挥发性，被发现对寡核苷酸的电喷雾荷质比分布和解吸效率都有显著影响。亨利定律常数（Henry's Law Constant）较高的烷基胺，如己胺、哌啶和咪唑，通过与寡核苷酸形成复合物并在气相中解离，从而降低寡核苷酸的荷质比分布；而亨利定律常数（Henry's Law Constant）极低的烷基胺则通过在电喷雾解吸过程的早期阶段促进离子发射来降低电喷雾荷质比分布。具有中等亨利定律常数（Henry's Law Constant）（k(H,cc)(aq/gas)）值的离子对试剂不会改变寡核苷酸的电喷雾荷质比分布，并且它们增强寡核苷酸离子化的能力遵循 k(H,cc)(aq/gas)值递减的顺序。亨利定律常数（Henry's Law Constant）还与酸性修饰剂对寡核苷酸电离效率的影响相关。己醇观察到了六氟异丙醇对寡核苷酸的电离增强效应，这归因于其低亨利定律常数（Henry's Law Constant）（k(H,cc)(aq/gas)）和中等酸度。还评估了烷基胺和六氟异丙醇对寡核苷酸电喷雾解吸的综合影响，发现酸碱平衡在确定这些影响方面起着关键作用。
