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High‐voltage contactless conductivity detection of underivatized amino acids in capillary electrophoresis
Author(s) -
Tanyanyiwa Jatisai,
Schweizer Karin,
Hauser Peter C.
Publication year - 2003
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200305422
Subject(s) - detection limit , amino acid , capillary electrophoresis , chromatography , histidine , conductivity , chemistry , electrolyte , lysine , electrophoresis , arginine , capillary action , analytical chemistry (journal) , biochemistry , materials science , electrode , composite material
High‐voltage contactless conductivity detection of underivatized amino acids in both acidic and basic media is demonstrated. The suitability of different acidic buffer solutions at pH values of about 2.5 was investigated with 12 amino acids. Lactic acid as background electrolyte gave the best results in terms of detection limits for arginine, lysine and histidine, which were approximately 2×10 ‐7 , 3×10 ‐7 and 4×10 ‐7 M , respectively. However, the sensitivity for other species was not quite as good and the detection limits in the order of 0.5–1×10 ‐5 M . The use of basic conditions at pH 10–11 generally led to more stable baselines and more consistent sensitivities. A range of 20 amino acids was investigated with alkaline buffers and detection limits were typically about 10 ‐6 M . Urine and beer samples were analyzed. Nine and eleven amino acids could be identified, respectively.