Investigation on liquid chromatographic separation of basic compounds using silica column with aqueous/organic mobile phase containing triethylamine and acetic acid.
A high-performance liquid chromatography (HPLC) method using silica column eluted with aqueous solvent mobile phase containing triethylamine (TEA) and acetic acid (ACH) at trace percentages was characterized for the analysis of basic compounds. The key mechanism of this system is ion-exchange accompanying interaction of silanol groups. The increase in the ACH concentration in the mobile phase minimizes the ionization of the silanol group, leading to reduced retention time. However, the greater extent of ionization of silanol caused by the increase of TEA concentration helps to retain basic compounds in the column. Further, the protonated TEA that is positively charged also competes for the ionized silanol group with basic compounds, resulting in the modification of retention time. On the other hand, the retention becomes longer with increasing proportion of either organic or aqueous solvent in mobile phase, and partial replacement of methanol with acetonitrile.
Wu
An-Bang
AB
Graduate Institute of Pharmaceutical Sciences, Taipei Medical University, Taipei, Taiwan, Republic of China.
Huang
Ming-Chun
MC
Ho
Hsiu-O
HO
Yeh
Geng-Cheng
GC
Sheu
Ming-Thau
MT
D019342:Acetic Acid / Q000737:chemistry*; D000468:Alkalies / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005021:Ethylamines / Q000737:chemistry*; D009930:Organic Chemicals; D012822:Silicon Dioxide; D013056:Spectrophotometry, Ultraviolet
D000468:Alkalies; D005021:Ethylamines; D009930:Organic Chemicals; D012822:Silicon Dioxide; D019342:Acetic Acid; C016162:triethylamine