Issue with Hanna low range PO4 Colorimeter

[HarryPotter]

So im not sure if I have terrible hand eye coordination or if it is simply impossible to get the entire contents (powder) of one reagent packet into the tiny test tube.

 

Like what the heck. The powder sticks in the packet, and when you flick it half the powder gets into the vial and half onto the table.

 

Whats up with this? Am I doing something wrong? It just seems impossible to pour the powder into the tiny vial from a paper packet.

 

Im concerned because the results vary greatly depending on how much is (Or isn't) spilled. Like from .19 to .07

[xmas_one]

Pro tip: empty the power out onto a square of aluminum foil before you start the test, when it comes time for the powder, gently bend the foil into a "U" shape and dump it in the tube.

 

Remember to wipe off any fingerprints before inserting tube into tester.

 

Also, rolling the tube on a flat surface will help get rid of the microbubbles that have a tendency to stick to the side of the tube and possibly throw off your reading.

[HarryPotter]

Pro tip: empty the power out onto a square of aluminum foil before you start the test, when it comes time for the powder, gently bend the foil into a "U" shape and dump it in the tube.

 

Remember to wipe off any fingerprints before inserting tube into tester.

 

Also, rolling the tube on a flat surface will help get rid of the microbubbles that have a tendency to stick to the side of the tube and possibly throw off your reading.

 

GENIUS! Love the foil idea, ill use that tomorrow. I wipe off fingerprints & roll for bubbles already.

 

Question:

Would missing powder cause an abnormally high or low reading?

[Jorgieee]

Create a funnel with paper or aluminum foil that should work.

[ManGups]

Or you can cut the packet from 2 sides and then try pour. I use the above method and never has any powder fall anywhere except the vial.

[seabass]

 

However, I use a small funnel. I assume that spilling some lowers the result, but that's just a guess.

[HarryPotter]

 

However, I use a small funnel. I assume that spilling some lowers the result, but that's just a guess.

 

Thanks for the video! Im going to try the double rip and the funnel method tomorrow.

[Admonition]

Or you can cut the packet from 2 sides and then try pour. I use the above method and never has any powder fall anywhere except the vial.

That's what I do- no issues.

[spinycheek]

 

 

 

Question:

Would missing powder cause an abnormally high or low reading?

 

Yes, yes it would. It would cause a low reading. Essentially what's happening is phosphate is invisible, the reagent is invisible, but when they combine, the colorimeter can now see them. So if there isn't enough reagent to react with all the phosphate in your vial, then the colorimeter won't see the unreacted phosphate. Too much reagent however will not affect the result, the important thing is that there is enough powder to react with all phosphate.

 

Now, floating reagent chunks, bubbles, fingerprints, scratches, etc can interfere and give high readings, so always check to make sure the vial is crystal clear and all contents have settled to the bottom (if not dissolved) before taking reading.