title: Exploring chip-capillary electrophoresis-laser-induced fluorescence field-deployable platform flexibility: separations of fluorescent dyes by chip-based non-aqueous capillary electrophoresis.
abstract: Microfluidic chip electrophoresis (chip-CE) is a separation method that is compatible with portable and on-site analysis, however, only few commercial chip-CE systems with laser-induced fluorescence (LIF) and light emitting diode (LED) fluorescence detection are available. They are established for several application tailored methods limited to specific biopolymers (DNA, RNA and proteins), and correspondingly the range of their applications has been limited. In this work we address the lack of commercially available research-type flexible chip-CE platforms by exploring the limits of using an application-tailored system equipped with chips and methods designed for DNA separations as a generic chip-CE platform - this is a very significant issue that has not been widely studied. In the investigated Agilent Bioanalyzer chip-CE system, the fixed components are the Agilent chips and the detection (LIF at 635 nm and LEDIF at 470 nm), while the chemistry (electrolyte) and the programming of all the high voltages are flexible. Using standard DNA chips, we show that a generic CE function of the system is easily possible and we demonstrate an extension of the applicability to non-aqueous CE (NACE). We studied the chip compatibility with organic solvents (i.e. MeOH, ACN, DMF and DMSO) and demonstrated the chip compatibility with DMSO as a non-volatile and non-hazardous solvent with satisfactory stability of migration times over 50h. The generic CE capability is illustrated with separations of fluorescent basic blue dyes methylene blue (MB), toluidine blue (TB), nile blue (NB) and brilliant cresyl blue (BC). Further, the effects of the composition of the background electrolyte (BGE) on the separation were studied, including the contents of water (0-30%) and buffer composition. In background electrolytes containing typically 80 mmol/L ammonium acetate and 870 mmol/L acetic acid in 100% DMSO baseline separation of the dyes were achieved in 40s. Linearity was documented in the range of 5-28 μmol/L, 10-100 μmol/L, 1.56-50 nmol/L and 5-75 nmol/L (r(2) values in the range 0.974-0.999), and limit of detection (LOD) values were 90 nmol/L, 1 μmol/L 1.4 nmol/L, and 2 nmol/L for MB, TB, NB and BC, respectively.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhaya Rd., Rajathevee, Bangkok 10400, Thailand.
authors.forename: Nantana
authors.initials: N
authors.lastname: Nuchtavorn
authors.forename: Petr
authors.initials: P
authors.lastname: Smejkal
authors.forename: Michael C
authors.initials: MC
authors.lastname: Breadmore
authors.forename: Rosanne M
authors.initials: RM
authors.lastname: Guijt
authors.forename: Philip
authors.initials: P
authors.lastname: Doble
authors.forename: Fritz
authors.initials: F
authors.lastname: Bek
authors.forename: Frantisek
authors.initials: F
authors.lastname: Foret
authors.forename: Leena
authors.initials: L
authors.lastname: Suntornsuk
authors.forename: Mirek
authors.initials: M
authors.lastname: Macka
mesh_terms: D000085:Acetates / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D046209:Electrophoresis, Microchip / Q000295:instrumentation* / Q000379:methods*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry / Q000302:isolation & purification*; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014867:Water / Q000737:chemistry
chemical_list: D000085:Acetates; D005456:Fluorescent Dyes; D014867:Water; C018824:ammonium acetate; D004121:Dimethyl Sulfoxide