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microprofiling:laboratory_microsensor_setup

Laboratory microsensor setup

In our laboratory microsensor setups (see photographs) we use the following components:

  • microelectrodes (made by our technicians, but can also be purchased from Unisense),
  • a heavy stand,
  • motorized linear positioners (VT-80 stage from Micos, equipped with a Faulhaber or Pollux motor, or LOT-Oriel motor),
  • a manual 3-axis micromanipulator (from Maerzheuser),
  • sensitive pA/mV-meters (built by our electronic workshop, but can also be purchased from Unisense),
  • a data aquisiton (DAQ) device (National Instruments devices, such as DAQ-16XA-50, DAQ-Pad 6015, DAQ-Pad 6020E, USB-6009),
  • a laptop, which needs
    • an RS232 connector for communication with the motorized stage (use USB→RS232 adapter, e.g., from Keyspan, if your computer does not have the RS232 connector),
    • a USB connector or PCMCIA slot for the DAQ device,
    • Microsoft Windows operating system (e.g., Win2000, WinXP),
  • accessories, e.g., shielded cables, flow-cells/aquaria, tubing, pumps, light sources, bubbling stones, etc.

How to assemble the microsensor setup

For a basic microsensor setup, you need approx. 1-1.5 sq-meter space and a vibration-free table. Follow these basic steps to assemble it:

  • Prepare microelectrodes (make them either by yourself, or order them from our TA's, or purchase them from Unisense).
  • Gather hardware mentioned above.
  • Attach the manual micromanipulator to the motorized stage.
  • Attach the motorized stage to the heavy stand (when using Micos stages, make sure that the stage is oriented with the motor upwards).
  • Connect pA/mV-meters to the DAQ device.
  • Connect the motorized stage and the DAQ device with the laptop.
  • Arrange everything (i.e., the flow-cell, tubing, pump, light source, pA/mV-meters, DAQ device, laptop, etc.) neatly on the table. Minimize possible sources of vibrations.
  • Attach sensors to the manual micromanipulator, connect them to the pA/mV-meters.

Test the hardware

Before you start the actual measurement, ensure that all the hardware is functioning reliably. Specifically, test

  • the movement of the motorized micromanipulator (using LINPOS-server):
    • check the optimum speed,
    • ensure that the downward movement corresponds to an increasing motor position,
    • familiarize yourself with the hot-keys (F1=up, F3=down, F2=stop),
  • the quality of your sensor signal, and how it is read by the computer (using MAX),
  • proper and reliable functioning of the accessories (e.g., constant pumping, illumination, air-flow, etc.),
  • calibrate the microelectrodes.

Start the measurement

Once all the components function properly, you can start the measurements. Below is a list of measurements that we usually conduct, and the corresponding program(s) that we use.

Measurement type Program(s) used
Automated microprofiling of analyte concentrations m-Profiler + LINPOS-server
Recording of analyte concentrations in time DAQ-server
Automated microprofiling of gross photosynthesis using the light-dark shift method Photo-m-Profiler + DAQ-server + LINPOS-server
Automated microprofiling of light spectra Spectral-m-Profiler + LINPOS-server + OOIBase32
Automated microprofiling of radioactivity Radio-m-Profiler

Automate complex experiments

Since the programs listed above are TCP/IP servers, one can combine any of the measurements listed above in a complex experiment, which can be automated in a specific timing protocol using the scripting approach implemented in G-client.

microprofiling/laboratory_microsensor_setup.txt · Last modified: 2013/09/10 10:55 by lpolerec

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