Everytime I'm mixing 2ml water (4 x 0,5ml BD syringes), I only ended up with 18 preloaded syringes (filled to the 10 marks = 500mcg).
So (20 marks) 1mg, disappears. Maybe the scale on BD syringes is wrong, or ?
Generally the syringes are near on perfect, especially with BD.
Have you ensured all of the liquid is gone? Turn the vial upside down and insert the needle only just past the rubber stopper then draw back. Some may be stuck in the neck of the bottle.
Another option is you're pulling out slightly more than 10 marks, this would only need to be 11.1 marks each to make up for the missing 20 marks overall; and that's quite easy to do if you're quickly prepping 20 syringes for storage.
Or it could be that you're putting slightly less water into the bottle to begin with, depending on your syringe size you could be doing as many as 4 transfers and could miss a small amount on each one.
>Turn the vial upside down and insert the needle only just past the
>rubber stopper then draw back. Some may be stuck in the neck of
>the bottle.
Exactly
>Or it could be that you're putting slightly less water into the bottle
>to begin with, depending on your syringe size you could be doing
>as many as 4 transfers and could miss a small amount on each one.
Yeah, I think there was some air in the syringes.
Thank you Tom