I'm using a hamilton syringe to inject mineral oil through PVC tubing attached to the needle tip of the syringe. To make sure the tubing stays free of bubbles, I have to get all the air out of the syringe, which I try to do by filling and expelling the syringe in a container of mineral oil until I stop seeing bubbles. However, no matter how many cycles of drawing and expelling, I keep getting tiny bubbles coming out of the tip, and they therefore show up in the oil-filled tubing when I eventually attach the tube.
I've tried every combination of drawing up the oil and expelling the oil at different speeds, including drawing up extremely slowly and expelling quickly, doing both slowly, etc. I've also tried inverting the syringe to let the air rise to the top and then expelling the oil to get the air out, but it doesn't work. Are there any other tricks to getting all the air out of a hamilton syringe filled with mineral oil?
Dear Jack,
Hamilton syringes are known for their quality standard when it comes to precision fluid measuring tools.
However, the presence of trapped air in syringes is a major threat to the this accuracy.
There are several ways that can help to check and eliminate this threat of trapped air to achieve a high precision of sample measurements. They include;
1. Make sure you immerse needle point 2-3mm into the solution until bubbles are no longer visible in the the syringe.
2. Draw and dispense sample info the solution until bubbles are no longer seen in the barrel.
3. This can also be achieved by turning the barrel in an upright position, allowing the trapped air to move towards the needle exit. Then dispense both the air and some of the sample solution until air bubbles are no longer observed in the syringe barrel.
Another way this can be achieved is by utilizing a smaller syringe (
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