We all know that surface tension affects our daily lives thru everyday applications like the ink you use in a pen, detergents for washing clothes, soap to clean your hands, paint for the house, just to name a few.  But Surface tension is more involved in your life than you may think.
Tap water is usually around 72 to 73 dynes/cm.  This can vary by temperature and other variables but for the sake of this blog post we will assume 73 dynes/cm.  Now this is where it gets interesting.  At 73 dynes/cm water will hydrate you.  Or does it?  You see, It is known that on a cellular level your body has to convert fluids to 45 dynes/cm to allow the water to penetrate the human cells.  Once water penetrates the cells it can hydrate and remove toxins from the cells.   If water cannot effectively penetrate human cells an accumulation can build up and over time cause the cells to die.  Amazingly, I have seen places around the world where people claim to have special water.  They claim their water has a lower surface tension and less colloidal minerals.  You knew this was coming..Yes, these same people have demonstrated good health as they easily live to be 100 years old!  And yes, they attribute this to their water.

Not surprisingly, I see web sites now that sell supplements to lower the surface tension of  water to improve your health.

Fact or Fiction you ask?
I think I am going to order some of these supplements and check it myself with a digital tensiometer!  As they say the proof is in the pudding. Or in this case the surface tension!

Stay tuned.  I will update my findings and how I did.

Thank You,
Gus

Novice: “Hi, I need to test for moisture and I need a Karl Fisher Titrator.  Can you tell me how much it costs?”

Expert: “O.K., do you need a Coulometric or Volumetric Karl Fisher Titrator?”

Novice: “uh what?”

Expert: “Well you see there are two kinds of Karl Fisher Titrators.  Depending on your sample size and the amount of moisture you expect to find -it may not only be advantageous but necessary to use a Coulometric vs. a Volumetric..and or vice versa.”

Novice: “I see.”  So how do I know what kind of Karl Fisher I need?

Expert: “Generally speaking, if you are working with small samples (0 to a few grams) AND the expected moisture is low (around 1% or less) you probably want to use a Coulometric Karl Fisher.  On the other hand, if your sample size is larger AND you expect to find a lot of moisture in the 2%+ range then you probably should consider a Volumetric Karl Fisher Titrator.”

Novice: “Do they both report moisture results the same way? You know, accuracy, resolution, repeatability?”

Expert: “Yes they do.  Both Volumetric and Coulometric Karl Fisher Titrators report moisture results in either Parts Per Million (PPM) or %.

Novice: “So then what makes them different?”

Expert: “Coulomeric Karl Fisher Titrators use a reagent called an Anolyte.  This Anolyte is 100% self contained and requires only an electrical current to cause a reaction where the Anolyte releases iodine.  It is this “iodine” that “neutralizes” the moisture inside the vessel.  A typical Coulometric Karl Fisher Titration Vessel can hold about 75mL of Anolyte.  The amount of Anolyte inside the vessel can only “release” so much iodine and therefore can only neutralize and measure a finite amount of moisture.  In this case using the 75mL as the example the reagent can only neutralize and measure 750,000 micro grams of moisture (water/H2O).  Now compare this to a Volumetric Karl Fisher and the game changes.  The Volumetric Karl Fisher method does not use a single self-contained Anolyte reagent that reacts to an electrical current.  Instead, the Volumetric titration is performed by “dripping” in IODINE at an precise amount into the titration vessel where there is a SOLVENT solution present in the vessel.

Novice: “How does the Volumetric Titrator “Drip in” IODINE into the vessel where the SOLVENT is located?”

Expert:”Good question.  It uses a buret that has a piston that moves up and down pulling The IODINE solution from a source bottle into and filling the buret and then pushing it out through tubing and into the vessel. ”

Novice: “Is there another name for this “IODINE solution”?  How do I get it?

Expert: “Another good question.  “This IODINE solution” is what makes the volumetric method so versatile when measuring larger amounts of moisture via Karl Fisher Titration.  The Iodine solution can come in two forms and with differing strengths.”

Novice:” Two forms?  Different strengths? Huh?

Expert: ” Yes, the two forms are referred to as “One-Component” and “Two-Component”.”

Expert: “The “One-Component” Iodine solution is referred to as Composite or Titer.  The Composite can come in 3 strengths; 1 (1mL of composition can consume 1mg or 1,000micro grams of water), 2 (1mL of composition can consume 2mg or 2,000micro grams of water) and 5 (1mL of composition can consume 5mg or 5,000micro grams of water).  We refer to these compositions as Composition-1 (aka Comp1), Composition-2 (aka Comp2), and Composition-5 (aka Comp5).

Novice: Differing Strengths.  Hmmm.  So for every 1mL you “drip in” it will consume, neutralize and measure the corresponding amount of moisture depending on the Composition strength.

Expert: “That’s right.  So for example if you use a Volumetric Karl Fisher Titrator with a 20mL buret you could conceivably introduce in one push of the piston that’s inside the buret, 20mLs of Composition.  If your using Comp5 you would be able to consume, neutralize and measure 20mL x 5,000 micro grams =100,000 micro grams of water.   Most Composition are sold in 500mL bottles.  So each bottle has the capacity to consume, neutralize and measure 2,500,000 micro grams of water.

Novice: “That’s a lot of water measuring capability!”

Expert: “Yes it is.”

This is a simple example and there are other factors to be considered for sure.  We thought this brief example would help those just getting started and trying to understand the basic comparison between Coulometic Karl Fisher and Volumetric Karl Fisher.

I suppose the refractometer market is kind of like the cell phone industry but with fewer manufacturers. I guess I’m glad then to see that Atago has not taken it’s foot off the accelerator when it comes to improving their products. Take the newest RX-5000i digital benchtop refractometer. It does not cost any more than the previous models, the RX5000alpha and the RX5000plus. Huh? Why? I think Atago wants to stay ahead of the competition by delivering a better product. So the new RX-5000i (and 5000iPlus) Digital Benchtop refractometers now have an improved user interface that incorporates a touch screen with seemingly easier navigation and operation. We will have to see how customers respond to this and let everyone know once the units have been out for awhile. Still, I do think the improved temperature range and the delay as well as the USB interface will be well received by customers.

You might be thinking, so what. I would probably agree with you but have you seen the news recently about oil spills? How about the one that just happened in the Gulf of Mexico? Since oil is less dense than water it floats. Look out Florida, Alabama, Mississippi, Louisiana, and Texas!

Liquids have different densities and will not mix if the difference in densities is great enough. Temperature is an important factor that can affect a liquids density too. In general, as liquid temperature increases, density decreases.

As you might expect knowing the density of a liquid serves numerous purposes and can provide valuable information for making decisions. Density can tell you how much sugar is in a can of soda, or how much gasoline and kerosene is in a petroleum product, or even aid someone in predicting how two or more liquids will interact. Understanding what density is, what affects density, and how density affects other physical properties is also important in using and translating this information into an everyday useful tool.

We live in a physical world and so it would make sense that we would want to be able to define these physical properties around us. Having a way to define these physical properties is helpful to those who need to use the information.
• How much space does it take up?
• How heavy is it?
• How much of this can we put into that?
• What is it?
• Many everyday products are packaged by volume but sold by weight
• Fluid properties; predictive correlations can be made if you know the density
• If we change some of the ingredients that make up the fluid property will it change the weight?

The neat thing about understanding liquid density is that it can answer not only the three basic questions; What is the mass (weight) of the liquid?, what is the volume of the liquid? What is the density of the liquid? But also, what is the liquid? Yes, we can actually compare liquids to grade and categorize them using a term known as specific gravity.
If you found this interesting stop back again as we explore further…

We have found that a number of Aquapal III users have been operating the Karl Fisher titrator without the seals that go with the caps on the vessel. If the seals are not used excessive ambient moisture can seep into the top of the vessel (headspace). If this is happening you may be seeing longer pre-conditioning times, higher drift values and higher reagent use.
We just want to remind the operators of the Aquapal III about the importance of this issue and that using the seals should be included in your every day use.  You may want to double check.
If you have any questions on this subject or have other technical concerns please contact us via email or give us a call.
I hope you find this information helpful.

After all of the sample has been injected immediately pull the needle from the vessel septa port and go directly back to the analytical balance to re-weigh the empty syringe.  Weigh the empty syringe and write that number down- this will be weight#2.

When the karl fisher titrator finishes and indicates that the test is complete the titrator should prompt you to enter weight#1 and weight#2.  After inputing both weights the karl fisher titrator will calculate the results for you.

Hope this is helpful.

H

If you would like to see this process you can watch it here:

Hello everyone!

We are currently in the middle of Pittcon 2009 and this seems to be a banner year for analytical chemistry and applied spectroscopy. I have heard there are a record number manufacturers and organizations that are unveiling breakthrough techniques and hardware systems. You can just feel the buzz of excitement giving you the impression that this year is going to be full of amazing discoveries.

Even with all to see and do here we still wanted to take a moment and let you know that when we are finished here, we are going to come back to the lab with a fresh new persepective and we will be ready to assist you in the months to come.