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United States Department of Agriculture

Agricultural Research Service

Title: Equations for Nickel-Chromium Wire Heaters of Column Transfer Lines in Gas Chromatographic-Electroantennographic Detection (Gc-Ead)

Author
item Byers, John

Submitted to: Journal of Neuroscience Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 12, 2003
Publication Date: March 1, 2004
Citation: BYERS, J.A. EQUATIONS FOR NICKEL-CHROMIUM WIRE HEATERS OF COLUMN TRANSFER LINES IN GAS CHROMATOGRAPHIC-ELECTROANTENNOGRAPHIC DETECTION (GC-EAD). JOURNAL OF NEUROSCIENCE METHODS. 2004. 135:89-93.

Interpretive Summary: Heating of chromatographic columns, transfer lines, and other devices is often required in neuroscience research. For example, the capillary column of a gas chromatograph (GC) can exit the instrument and direct volatile odors to an insect antenna (called an electroantennographic detector, EAD). The capillary column is passed through a heated transfer line to prevent condensation of chemicals in the tube that would otherwise occur at room temperature. Construction of such a transfer line heater is described using (80/20%) nickel-chromium heating wire wrapped in a helix and powered by a 120/220 volt AC rheostat. Methods and equations were developed using a computer program to estimate the voltage at which a rheostat should be set to obtain the desired heater temperature for a specific coil. The coil attributes (number of loops, width, or length of each loop) are input by the user. Other input variables include AWG size of heating wire, radius of helix, and desired heater temperature. The program calculates total length of wire in the helix, resistance of the wire, amperage used, and the voltage to set the rheostat. A discussion of methods of isolation of behavioral chemicals (pheromones and semiochemicals) of insects using the GC-EAD and bioassays is presented.

Technical Abstract: Heating of chromatographic columns, transfer lines, and other devices is often required in neuroscience research. For example, the capillary column of a gas chromatograph (GC) can exit the instrument and direct volatiles to an insect electroantennographic detector (EAD) or olfactory sensillum. The capillary column is passed through a heated transfer line to prevent condensation of chemicals in the tube that would otherwise occur at room temperature. Construction of such a transfer line heater is described using (80/20%) nickel-chromium heating wire wrapped in a helix and powered by a 120/220 volt AC rheostat. Algorithms were developed using a computer program to estimate the voltage at which a rheostat should be set to obtain the desired heater temperature for a specific coil. The coil attributes (number of loops, width, or length of each loop) are input by the user. Other input variables include AWG size of heating wire, radius of helix, and desired heater temperature. The program calculates total length of wire in the helix, resistance of the wire, amperage used, and the voltage to set the rheostat. A discussion of semiochemical isolation methods using the GC-EAD is presented.

Last Modified: 10/24/2014
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