PART 2 -GETTING IT RIGHT--MAKE TESTING COUNT BY USING A QUALITY SYSTEM APPROACH---COLORIMETRIC...

[Rick Mathew]

If one graduates to using a Micro Pipette for one's testing (where appropriate), what is the procedure for cleaning it before moving on to the next test with different reagents?

Actually that is the beauty of these Single Channel Pipettes...When you are done with a test you "eject" the tip...put on a new one and your off to your next test...The replacement tips are inexpensive...the 1 mL ar 2 cents each or so...No cleaning necessary!

You do need to calibrate them...I do mine once a month or if I suspect a problem and they need some maintenance about once a year or so ....

 

[Bills beginning]

Very good information and read. This will definitely help me out with my testing procedures and to improve process to eliminate errors. Looking forward for next installment.

 

[Rick Mathew]

Very good information and read. This will definitely help me out with my testing procedures and to improve process to eliminate errors. Looking forward for next installment.

Thank you very much...very glad it was helpful..

 

[radiata]

Your Figure 7 appears to be the 'Four E's Scientific Lab Single-Channel Pipettor Adjustable Micro Pipette 1-10mL' on the referenced Amazon page. Is this correct, and is it the one you use?

 

[Rick Mathew]

Your Figure 7 appears to be the 'Four E's Scientific Lab Single-Channel Pipettor Adjustable Micro Pipette 1-10mL' on the referenced Amazon page. Is this correct, and is it the one you use?

That is correct...I also use the Four E 0 to 1 mL and the 0 to .1 mL (This is the one I use for the Hanna Calcium Test

 

[Rick Mathew]

Another great article! Thanks @Rick Mathew!

Daniel: I hope to post Part 3 of the Article some time today on the Reef Chemistry Forum...Just thought I would give you a heads up

ricl

 

[Rick Mathew]

Another great article! Thanks @Rick Mathew!

Daniel: I just posted Part 3

 

[Sisterlimonpot]

Some tests require us to add a prescribed number of measuring spoon of a dry reagent to the reaction vessel. If you read the instructions it will often say “Add One Leveled measuring spoon to the vial” The word that is often missed or ignored is “Leveled”. Many tests provide pictorial instructions that show the steps of the chemistry to be preformed. If a measuring spoon is required they just show the reagent being added with the spoon…They don’t show the “Leveling” part. You have to read the instructions to find that part. Not leveling the spoon will result in the addition of too much or too little reagent and introduce variability in the process resulting in reduced accuracy and precision.

Man! I was soooo hoping to finally read a solid answer to a concern I've had for years about using spoons.

Every time I test nitrates with the salifert kit (If you're not familiar with it, it uses a fine powder), I always wonder what the best practice for scooping it. I get the leveling aspect, but it always baffled me whether i'm supposed to pack the powder into the spoon or simply scoop it? I would imagine that you would have more control and consistency if you pack it, but I also could see the argument for doing the opposite...

Any insight on that?

 

[Rick Mathew]

Man! I was soooo hoping to finally read a solid answer to a concern I've had for years about using spoons.

Every time I test nitrates with the salifert kit (If you're not familiar with it, it uses a fine powder), I always wonder what the best practice for scooping it. I get the leveling aspect, but it always baffled me whether i'm supposed to pack the powder into the spoon or simply scoop it? I would imagine that you would have more control and consistency if you pack it, but I also could see the argument for doing the opposite...

Any insight on that?

I have pondered the very same question...I contacted a supplier and asked them. Here is the incite they gave me.

Some reactions are sensitive to the ± amounts of reagents while others only need a minimum amount of reagent for the reaction to proceed. Most suppliers have developed their tests so that the measured amount ( spoon) with some ± amount so as to give relatively consistent results...meaning if it is a little over filled or under filled it does not drastically impact the results...My goal has been consistency...Do it the same way every time...This improves my chances of good precision...So I level out the measuring spoon with a straight edge spatula...I do not "pack" at all....I am not aware of any kit instructions that indicate I would need to do so although there are kits that say "level" spoon full....so I scoop it out...level it off and add it to the test vial.

Hope this helps

rick

 

[Rick Mathew]

Man! I was soooo hoping to finally read a solid answer to a concern I've had for years about using spoons.

Every time I test nitrates with the salifert kit (If you're not familiar with it, it uses a fine powder), I always wonder what the best practice for scooping it. I get the leveling aspect, but it always baffled me whether i'm supposed to pack the powder into the spoon or simply scoop it? I would imagine that you would have more control and consistency if you pack it, but I also could see the argument for doing the opposite...

Any insight on that?

Also...If you are interested this is how I test for Nitrates

https://www.reef2reef.com/ams/test-meter-for-testing-nitrates.599/

 

[Tim Olson]

Great article and very helpful! It looks like I need some more accurate syringes and at least one of those Single Channel Micro Pipettes. I've also struggled with getting the powder to be level in the tiny spoons in my Salifert test kits. There must be a better way to measure the powders, but I haven't seen one. Thanks for taking the time to share you knowledge.

 

[Rick Mathew]

Great article and very helpful! It looks like I need some more accurate syringes and at least one of those Single Channel Micro Pipettes. I've also struggled with getting the powder to be level in the tiny spoons in my Salifert test kits. There must be a better way to measure the powders, but I haven't seen one. Thanks for taking the time to share you knowledge.

Tim...Thank you for the nice complement....The question of the use of the spoon is a good one...Here is some information I posted in response to the same question...I have actually done the measurement on the leveling of the spoons and it does help the measurement precision...as I indicated in the article

Some reactions are sensitive to the ± amounts of reagents while others only need a minimum amount of reagent for the reaction to proceed. Most suppliers have developed their tests so that the measured amount ( spoon) with some ± amount so as to give relatively consistent results...meaning if it is a little over filled or under filled it does not drastically impact the results...My goal has been consistency...Do it the same way every time...This improves my chances of good precision...So I level out the measuring spoon with a straight edge spatula...I do not "pack" at all....I am not aware of any kit instructions that indicate I would need to do so although there are kits that say "level" spoon full....so I scoop it out...level it off and add it to the test vial.

Hope this helps

 

[romassomar]

Thats some really nice article! Translation and localization

 

[Rick Mathew]

Thats some really nice article! Translation and localization

Thank you.

 

[Silent]

So many reefers will benefit from the syringe reading portion of this article. There are numerous threads with many people confused about this. Thank you

 

[Rick Mathew]

So many reefers will benefit from the syringe reading portion of this article. There are numerous threads with many people confused about this. Thank you

Most welcome....

 

[itgoeson]

Why do you measure including the bubble? I thought for titration you had to remove as much air as possible and then fill to the top the liquid rather than the bubble! Is it something to do with the removable tip? I can’t seem to ever get 0.1ml worth of bubble out of those! (Am referring to Red Sea ca/alk/mg tests, for context.). Thank you!

 

[Rick Mathew]

Why do you measure including the bubble? I thought for titration you had to remove as much air as possible and then fill to the top the liquid rather than the bubble! Is it something to do with the removable tip? I can’t seem to ever get 0.1ml worth of bubble out of those! (Am referring to Red Sea ca/alk/mg tests, for context.). Thank you!

If I understand your question correctly it is a function of the removable tip (fig 5)....Many of the kits with syringes with removable tips tell you to ignore the "air" at the top of the syringe...I know what you mean about getting .1mL out of the tip...I actually took several of them and by measuring the weight in grams of water from a fully discharges syringe picked the one that was closest to 1.00 grams of RODI water to be sure I was getting a good measurement...most of them were pretty close but getting all of that last .1 in the tip was the difference...I think it had more to do with the syringe plunger and maybe the cylinder construction...not sure

 

[itgoeson]

getting all of that last .1 in the tip was the difference

The only way I’ve found to get that last bubble out is to point the tip up, tap the syringe, and squirt some reagent up and out (and then add more from the bottle) - which I don’t love doing because it gets reagent on me and I’m not sure that’s particularly safe. Is there a better way?

If I just leave that 0.1mL bubble in there, do I pull the stopper past 1.0mL so that the top of the liquid/bottom of the bubble is at 1.0 (rather than 0.9 as it would be with the stopper at 1.0) and read the result at the top of the liquid?

My question is based on this photo, as I’ve been reading from the “not here” line!

I guess it probably doesn’t matter as long as I pull it so the liquid is at 1 to start - then read at the top of the liquid, should be the same as pulling the stopper to 1 and reading at the stopper if I’m measuring the amount used. Think I’m over complicating!

These articles are incredibly helpful, by the way - thank you!!

 

[Rick Mathew]

The only way I’ve found to get that last bubble out is to point the tip up, tap the syringe, and squirt some reagent up and out (and then add more from the bottle) - which I don’t love doing because it gets reagent on me and I’m not sure that’s particularly safe. Is there a better way?

If I just leave that 0.1mL bubble in there, do I pull the stopper past 1.0mL so that the top of the liquid/bottom of the bubble is at 1.0 (rather than 0.9 as it would be with the stopper at 1.0) and read the result at the top of the liquid?

My question is based on this photo, as I’ve been reading from the “not here” line!

I guess it probably doesn’t matter as long as I pull it so the liquid is at 1 to start - then read at the top of the liquid, should be the same as pulling the stopper to 1 and reading at the stopper if I’m measuring the amount used. Think I’m over complicating!

These articles are incredibly helpful, by the way - thank you!!

You are correct...You read from the plunger and not the liquid line...the air space in between the plunger and the liquid is due to the tip...So when I fill I place the tip in the solution draw the plunger all the way to the top...passed the 1.0 mark...I then press the plunger all the way down to empty the syringe...Keeping the tip submerged in the liquid...I repeat this 2-3 times to be sure all the air is out. Then I draw the plunger all the way to the top of the chamber and move it down to the 1.0 mark...like is shown in the picture above...Hope this helps