Development of a Liquid-Junction/Low-Flow Interface for Phosphate Buffer Capillary Electrophoresis Mass Spectrometry

• Published in: Analytical chemistry (Washington) Vol. 81; no. 7; pp. 2810 - 2814
• Main Authors: Li, Fu-An, Huang, Ju-Li, Shen, Shang-Yu, Wang, Che-Wei, Her, Guor-Rong
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-04-2009
• Subjects: Analytical chemistry; Buffers; Carboxylic Acids - analysis; Carboxylic Acids - chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Electrophoresis, Capillary - instrumentation; Equipment Design; Exact sciences and technology; Histamine Antagonists - analysis; Hydrogen-Ion Concentration; Ions; Mass spectrometry; Mass Spectrometry - instrumentation; Other chromatographic methods; Phosphates; Phosphates - chemistry; Spectrometric and optical methods; Phosphates; Capillary electrophoresis; Liquid junction; Buffer solution; Mass spectrometry; Electrospray; Chemical ionization
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac802491y

To alleviate ion suppression from phosphate buffer and to preserve separation integrity, a new capillary electrophoresis mass spectrometry (CE−MS) interface was developed. The interface consisted of a low-flow interface and a liquid junction. In this design, both the inlet reservoir and the liquid-junction reservoir were filled with phosphate running buffer. Because the phosphate anions in the column migrated toward the inlet reservoir (away from the electrospray ionization (ESI) source) the problem of ion suppression in ESI was avoided. The liquid junction was incorporated to eliminate issues of degraded separation observed when sheath liquid interfaces use different buffers for separation and MS analysis attributed to differences in anion velocity. The utility of the interface was demonstrated by the analysis of antihistamines at pH 3.5 and the analysis of perfluorocarboxylic acid at pH 9.5.