CE-MS of antihistamines using nonvolatile phosphate buffer.
Antihistamines were analyzed by CE-ESI-MS using phosphate buffer. The separation was performed in an acidic environment so that phosphate ions had a net velocity flowing toward the inlet reservoir instead of the ESI source. To further reduce the effect of ion suppression, the sodium ion in sodium phosphate was replaced with an ammonium ion. Furthermore, with the combination of reducing the concentration of acid added to the sheath liquid and the use of a low-flow interface, phosphoric acid could be added to the sheath liquid. Because of the use of the same counterion (phosphate ion) in running buffer and in sheath liquid, the separation integrity (resolution, elution order, and peak shape) was preserved. In addition, ion suppression was also greatly alleviated because a minimal amount of phosphate flowed into the ESI source.
Chien
Chiu-Tang
CT
Department of Chemistry, National Taiwan University, Taipei, Taiwan.
Li
Fu-An
FA
Huang
Ju-Li
JL
Her
Guor-Rong
GR
D002021:Buffers; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D006634:Histamine H1 Antagonists / Q000032:analysis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D010710:Phosphates / Q000737:chemistry*; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods; D014835:Volatilization
D002021:Buffers; D006634:Histamine H1 Antagonists; D010710:Phosphates; C024788:ammonium phosphate