Cuvette Holder Use
The FTA temperature stabilized cuvette holder holds standard 10 x 10 x 45mm polystyrene or quartz cuvettes. Special PTFE caps with needle holes seal the cuvette when the liquid is volatile or when the cuvette is turned upside down for bubble-up measurements. The holder completely encloses the cuvette and can be thermostated with a user-supplied circulating bath.
Special care must be taken to not dirty the outside of the cuvette while handling it, because the microscope must look through the sides to see the drop.
In general, make sure the cuvette holder is mounted so the needle falls in the center of the image. If necessary, adjust the camera orientation or slide the holder left-right to center the needle. The holder has about a 1/2mm of adjustment in its mounting screws. Do this adjustment before any liquid is introduced into the system; it is easier done while dry.
Lift the syringe and needle so there is a clear path for the cuvette into the holder.
The holder has a removable top, held in place by a thumbscrew. This is important when maximum temperature stability is required, as it completes the enclosure of the cuvette within the holder. It is also necessary when the cuvette is used upside down.
For Normal Pendant Drop Orientation...
Place the dry cuvette in the holder.
Fill the cuvette with liquid, but leave an expansion gap at the top.
Place the PTFE cap on the needle first so you can clean the end of the needle: it may pick up particles while being inserted into the seal cap.
With the needle, plus cap, on the syringe, lower the syringe so the cap comes into place on the cuvette.
Replace the cuvette holder cap, if desired. Fasten down with thumbscrew.
Dispense liquid into the cuvette to form the normal pendant drop.
For Upside-Down Bubble-Up Orientation...
A Luer fitting tubing assembly connects the syringe to the dispense needle in the upside-down mode.
Adjust the position of the cuvette holder first, as discussed above.
Fill the cuvette while it is standing on the bench, and insert the cap and needle, following the previous general instructions.
Insert the cuvette into the holder and place the holder cap on to ensure it stays in place.
To Remove a Cuvette...
There is a button on the bottom of the holder that will pop the cuvette up for easy removal from the holder.