Abstract
The sensitivity of miniaturized chemical analysis systems depends most of the time on the obtainable detection limit. Concentrating the
analyte prior to the detection system can enhance the detection limit. In this writing an analyte concentrator is presented that makes use of
evaporation to increase the ion concentration of an electrolyte. The evaporation rate can be enhanced using forced convection. In order to
control the evaporation rate a nitrogen flow is fed over a liquid channel covered with a hydrophobic vapor permeable membrane.Water vapor
can pass through this membrane in contrast to water itself because of the hydrophobic nature of the membrane surface. An electrolyte
conductivity detector is used to measure directly the concentration effect as a function of the nitrogen flow velocity. The influence of the
convective nitrogen flow and the residence time of the analyte inside the concentrator are investigated in this paper. It is shown that the
evaporation rate is enlarged with an increase in convective flow. The concentration effect is also enhanced when the residence time of the
analyte inside the concentrator is increased. The higher concentration enhancement due to the longer residence time, however, results in an
increase in water vapor present in the nitrogen flow. This results in a lower normalized evaporation rate when the available evaporation time is
enlarged.
Original language | Undefined |
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Pages (from-to) | 342-347 |
Number of pages | 6 |
Journal | Sensors and Actuators B: Chemical |
Volume | 91 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2003 |
Keywords
- METIS-214008
- Electrolyte solution concentrator
- Micromachined membrane
- IR-46079
- Evaporator