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A miniaturized evaporative light scattering detector (ELSD) compatible with packed microcolumn high‐performance liquid chromatography (HPLC) has been developed. In such a detector, it is particularly important that an efficient nebulization of the column effluent is achieved. Therefore, the geometry of the nebulizer has been optimized. Detector performance was demonstrated for acetonitrile–acetone at 5–100 μL min−1 as mobile phase, a packed microcolumn, 0.7 mm i.d. was used. Isocratic and gradient elutions were performed. Detection limit was lower than 8 ng. Linear range was 30–300 ng. Quantitative analysis of cohune oil components separated on a C‐18 column using gradient elution was examined. The relative standard deviation (RSD) in peak areas was 1.9–3.7% for large peaks. Minor peaks gave higher RSD. © 1998 John Wiley & Sons, Inc. J Micro Sep 10: 249–254, 1998

The distribution of ions in a capillary with both pressurized flow and an electric field has been studied. We have earlier reported that the overall concentration of ions increase in a capillary with high electric field and a pressurized flow. Now we describe how the ions are distributed in the capillary both along the capillary length and in the radial direction as a result of the parabolic flow profile. We have combined current measurements with finite element techniques in order to get better understanding of the system. We have found that the concentration of the ions that because of the electric mobility moves towards the flow primarily increases at the beginning of the electric field and close to the capillary wall. In view of the results we have proposed an alterative explanation of earlier published results concerning voltage-induced variation in capacity factors.

Ž. Abstract: A miniaturized evaporative light scattering detector ELSD compatible Ž . with packed microcolumn high-performance liquid chromatography HPLC has been developed. In such a detector, it is particularly important that an efficient nebulization of the column effluent is achieved. Therefore, the geometry of the nebulizer has been optimized. Detector performance was demonstrated for ace-tonitrile᎐acetone at 5᎐100 L min y1 as mobile phase, a packed microcolumn, 0.7 mm i.d. was used. Isocratic and gradient elutions were performed. Detection limit was lower than 8 ng. Linear range was 30᎐300 ng. Quantitative analysis of cohune oil components separated on a C-18 column using gradient elution was examined.Ž . The relative standard deviation RSD in peak areas was 1.9᎐3.7% for large peaks. Minor peaks gave higher RSD.