Hannah Checker, do you use the tip?

[rocko918]

So someone asked me lastnight while visiting my house, when i do the hannah alk test, do i use the tip. I said i always use the tip to get the 1 ml. he said why? 1 ml is 1ml. i really didn't have an answer for him. I said because that is what it says to do.

so anyone have a better answer on why i should or should not use the tip on the plunger?

thanks

 

[CalmSeasQuest]

I've read arguments on both sides of increased accuracy. I use it so I don't have to rinse the syringe after each test. With the tip, the syringe never comes in contact with the reagent.

 

[feh]

I don't use the tip. The syringe that came in my kit works better without it. Its also easier to tap the air out to get a more accurate measure without it, but if it works for you I see no need to change things. I do wish the Ca reagent refills came with new syringes like the Alk refills.

 

[-Logzor]

I don't use the tip, if I do the reagent just drains out...

 

[swissgaurd]

i use a salifert tip works well simple ,dont have to worry about air

vic

 

[rocko918]

I don't use the tip, if I do the reagent just drains out...

When i bought a refill the new tip did this. so i just used the old one.

 

[Dowtish]

I dont use the tip to draw up the reagent. It seems to draw up better without it. Less air and bubbles. and I feel like I get exactly 1ml without having to guess with those gaps or bubbles.

 

[CalmSeasQuest]

When i bought a refill the new tip did this. so i just used the old one.

+1 I think I'm still using the original tip as the 10 or since received with refills fit too loosely to be effective. I found it to be very accurate - I initially fill the syringe with more than 1mL, then push the plunger back to the 1mL mark.

 

[ritter6788]

I don't use the tip. Never thought much about it. Not sure if it effects the final number or not so maybe I'll find out. I'm more concerned with a stable alk than a 100% accurate one.

 

[mcarroll]

I don't use the tip. The syringe that came in my kit works better without it. Its also easier to tap the air out to get a more accurate measure without it, but if it works for you I see no need to change things. I do wish the Ca reagent refills came with new syringes like the Alk refills.

Two things here.

1) The initial Hanna kits had the various parts literally crammed into the case, so the tips were a bit misshapen from being compressed during storage/shipment. If you leave them out, they will generally regain the proper shape and thus be able to seal properly around the syringe without letting air creep in. (Newer cases have a different plastic molding inside the case which has room for the tip, preventing this issue.) I will say that once I figured out what the problem was, I was even able to get a good seal on my original "mushed" tip 99% of the time just by seating it very firmly on the syringe. Also, on another question, yes I would recommend using the tip vs not. As another person wrote, the tips are "non-wetting" and don't keep drips of fluid stuck inside of them as easily as the syringe material does. It also will give you smaller drop sizes than the naked syringe tip. This can all add up to a little higher test resolution (as intended by the kit maker) vs the large drops from the naked syringe.

2) Tapping out air from your syringe is not necessary and can even throw off your measurements. As long as your syringe (and tip) has no air gaps, your plunger begins at the "zero" position and your tip stays submerged while drawing in sample/reagent, then the air that's in the syringe between the plunger and liquid is the correct amount of air, and when you draw the plunger up to (e.g.) 1 mL, you have 1 mL of stuff in the syringe. Tapping air out and getting more liquid liquid in will obviously alter the measurement of sample/reagent by an unknown amount and have a corresponding impact on your test result. (The effect of this mis-measurement can be greater or lesser depending on the stuff you are mis-measuring and the test you are running.)

-Matt