YSI 2700 Select Biochemistry Analyzer

Simple Protocol for Everyday Use

The simple procedure for running your sample is

1. Turn on the instrument. The power supply is (as you face the instruments) on the lower left hand side of the back panel.
2. After you turn it on, turn the instrument to run mode using the LCD menu and keypad.
3. Wait for the machine to auto-calibrate.
4. Hit “Run Sample”. This will summon the manual injection needle from its housing and cause it to extend from the upper left front of the unit.
5. After the aspiration needle is still and fully extended, carefully hold your sample-containing test tube so that the needle tip is immersed in the sample. While holding the sample in this position, hit “Aspirate Sample”.
6. Hold your sample until the aspiration needle withdraws back into the unit’s housing.
7. Wait for the analysis of your sample to be completed and for the results to display on the LCD screen.
8. Repeat 4 -7 as desired.
9. When you are finished, change the instrument to “Standby” mode in the front control panel.
10. Turn off the YSI 2700 Select Biochemistry Analyzer.

Special Notes:

• Every 5 – 6 samples, the machine will automatically recalibrate itself to make sure that the current measured for reference standards is not drifting too far from the previously established calibration. The autocalibration takes some minutes to complete. Be patient.
• Periodically, buffer tanks run low and enzyme electrodes need to be replaced. See Jose for advice on how to do this.

Periodic Maintenance: Changing the Membrane Electrodes

1. Make sure you have purchased unexpired membrane electrodes from YSI, and have them ready at the instrument. Make sure the instrument in powered off.
   1. For reference, some commonly used membranes:
   2. Glucose #### blah blah
2. Open one of the four membrane compartments.
3. Use salt solution (part ###) to wet the surface of the membrane. Be careful not to touch the membrane during this process.
4. Open the YSI front casing by pulling on the left side of the instrument.
5. Unscrew the electrode (L=lactate, G=glucose) you intend to change.
6. Using tweezers, carefully remove the old membrane from the electrode.
7. Wash the electrode with salt solution, and blot dry with a kimwipe.
8. Repeat the previous step several times.
9. Carefully press the clean electrode tip onto the bead of salt solution which is wetting the new membrane. Capillarity will make the membrane stick to the electrode surface.
10. Turn the electrode over, making sure not to separate the membrane from the electrode in the process.
11. Carefully move the membrane into place by pressing with tweezers *only on the rubber septum which borders the membrane*. Do not touch the membrane directly.
12. Blot any excess droplets of salt solution away from the electrode casing.
13. Rescrew the electrode into the housing chamber.
14. Close the YSI and turn on its power.
15. Press Menu, Service, blah blah blah, and monitor the current.
16. Periodically press "flush" until the basal currents for each membrane are under 5 nA.
17. Exit from the "monitor" mode. The YSI is ready to put into run mode! After the machine autocalibrates itself, it will be ready to use.

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