Quantification of 5-aminolevulinic acid by CE using dynamic pH junction technique

Bo Chuan Hsieh, Richie L.C. Chen, Tsuimin Tsai

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


An online dynamic pH junction preconcentration method was developed for quantification of 5-aminolevulinic acid (ALA) by CE with the separation time less than 6 min. The optimal dynamic pH junction of ALA was carried out between pH 9.3 borate buffer (BGE, 40 mM) and pH 2.5 phosphate buffer (sample matrix, 40 mM) when 4.1 cm of sample plug was hydrodynamically injected into an uncoated fused-silica capillary (48.5 cm in length, id of 50 μm). If a 24 kV separation voltage was applied, the calibration curve of ALA peak area (200 nm) showed good linearity (R2 = 0.9991) ranging from 0.01 to 6.5 mg/mL. The reproducibility of this system was excellent with RSDs (n = 10) of 2.5% for peak area response and 0.6% for migration time at ALA concentration of 0.5 mg/mL. The LOD was evaluated as 1.0 μg/mL (S/N > 3). Compared to conventional CE procedure, the sensitivity was successfully improved over 50-fold. The analytical results of pharmaceutical formulations show a good agreement with those by HPLC (r = 0.94).

Original languageEnglish
Pages (from-to)803-808
Number of pages6
JournalJournal of Separation Science
Issue number4
Publication statusPublished - Feb 2013


  • 5-Aminolevulinic acid
  • CE
  • Dynamic pH junction

ASJC Scopus subject areas

  • Analytical Chemistry
  • Filtration and Separation


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