The use of a multichannel capillary for electrophoretic separations of mixtures of clinically important substances with contactless conductivity and UV photometric detection
Abstract
A fused silica capillary with a common outer diameter, 360 μm, but containing seven internal channels, each 28 μm in diameter (a multi-channel capillary), has been tested on electrophoretic separations of mixtures of dopamine, adrenaline and noradrenaline, using a contactless conductivity and UV photometric detection. It has been demonstrated that the sensitivity of the detection of these neurotransmitters in multi-channel capillary, in comparison with those obtained for a standard single-channel capillary with similar cross-sectional area, is comparable to that for the contactless conductivity and of about 50% higher for the UV photometry.
The sensitivity is increased without loss of the separation efficiency, in contrast to UV detection with bubble cell. Further possibilities of using a multi-channel capillary are demonstrated on separations of mixtures of inorganic cations (K(+) , Ba(2+) , Na(+) , Mg(2+) , and Li(+) ) and mixtures of glucose and ribose.
The main advantage off multi-channel capillary in comparison with a single-channel capillary with the same cross-sectional area becomes apparent in separations in background electrolytes of high conductivity.