title: Highly sensitive wavelength-dependent nonaqueous capillary electrophoresis for simultaneous screening of various synthetic organic dyes.
abstract: A novel multi-wavelength nonaqueous capillary electrophoresis (MW-NACE) technique based on wavelength-dependent laser-induced fluorescence (LIF) detection was investigated for the simultaneous screening of various synthetic organic dyes. Multi-wavelength excitation light sources were utilized to excite different organic dyes [e.g., 543 nm for crystal violet (CV), methyl violet B (MVB), methyl violet B base (MBB), rhodamine 6G (R6G), and rhodamine B base (RBB); 635 nm for nile blue A (NBA) and methylene blue (MB)] simultaneously. Using a nonaqueous buffer system composed of 15 mM sodium borate and 835 mM acetic acid in 100% ethanol (pH=5.4), all dyes were analyzed within 15 min with excellent resolution (R≥4.0) under an electric field of 500 V/cm. Calibration curves showed excellent linearity with square of correlation coefficients (r(2)) greater than 0.9908 over wide dynamic ranges of 0.4-50 μM for CV, 0.8-50 μM for MVB, 1.5-50 μM for MBB, 0.08-5 nM for R6G, 0.06-10 μM for MB, 0.02-10 μM for NBA, and 0.13-10 pM for RBB. The detection limits (S/N=3) of 40 fM to 0.5 μM were 10-200,000 times lower than those of previous detection methods. While adjacent peaks were not well distinguished with baseline separation in a single capillary, the devised technique was faster and more sensitive than conventional aqueous and nonaqueous CE approaches, thereby enabling the quantitative analysis of various dyes based on wavelength-dependent fluorescence detection with different excitation wavelengths.
authors.affiliation: Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea.
authors.forename: Moonhee
authors.initials: M
authors.lastname: Park
authors.affiliation: Criminal Investigation Command of MND, Seoul 04383, Republic of Korea.
authors.forename: Seung-Hoon
authors.initials: SH
authors.lastname: Bahng
authors.affiliation: Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea.
authors.forename: Nain
authors.initials: N
authors.lastname: Woo
authors.affiliation: Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea; Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea. Electronic address: shkang@khu.ac.kr.
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Kang
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D001881:Borates / Q000737:chemistry; D002021:Buffers; D002138:Calibration; D004396:Coloring Agents / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D000431:Ethanol / Q000737:chemistry; D044707:Forensic Sciences / Q000295:instrumentation / Q000379:methods*; D005840:Gentian Violet / Q000302:isolation & purification; D006801:Humans; D007281:Ink; D057230:Limit of Detection; D008751:Methylene Blue / Q000302:isolation & purification; D010078:Oxazines / Q000302:isolation & purification; D012235:Rhodamines / Q000302:isolation & purification
chemical_list: D001881:Borates; D002021:Buffers; D004396:Coloring Agents; D010078:Oxazines; D012235:Rhodamines; C026188:rhodamine 6G; C008619:Nile Blue; D000431:Ethanol; C010634:sodium borate; D005840:Gentian Violet; C029773:rhodamine B; D019342:Acetic Acid; D008751:Methylene Blue
keywords: Laser-induced fluorescence; Multi-wavelength detection; Nonaqueous capillary electrophoresis; Organic dyes