Although the CSC Scientific Interfacial Tensiometer is fundamentally very straight forward, it is helpful to have a basic understanding of the operational features and components of the tensiometer.  There are dials, clamps, Du Nouy Rings, and Verniers to consider. 

In this video we show you how to check your calibration using a given weight. 

To conduct this calibration check we assume the tensiometer's tension wire is secure and the unit has the ability to provide a stable reading for your given samples.  Take a look at this short video and let us know if you have questions about the process.

Most everyone working with Karl Fischer Titration at some point ends up wanting to check their instrument for accuracy and overall operational readiness.  Karl Fischer Water Standards were made to assist operators with making these operational checks.  Sometimes however we find there is some confusion about the choice of water standards available and what the numbers mean.

Karl Fischer Titration Water Standard Video from Scientificgear on Vimeo.

Hydranal water standards provide a few popular choices for both coulometric and volumetric Karl Fischer Titrators:

• Hydranal 0.1 (100PPM ±10% error acceptance)
• Hydranal 1.0 (1,000PPM ±3% error acceptance)
• Hydranal 10.0 (10,000PPM)

So what do the numbers mean?  0.1, 1.0, 10.0?

Simply put, these numbers tell us the amount of moisture (H2O) that is present in 1 gram of the water standard.  The amount of moisture (H2O) is expressed as milligrams on the packaging.  Using the Hydranal 1.0 for example we say there is 1.0 milligram of moisture (H2O) in 1 gram of the water standard.  Did you know there are 1,000 micrograms per 1.0 milligram?  Yes there is.  So instead of thinking in terms of 1 milligram per 1 gram of water standard, think in terms of 1,000 micrograms per 1 gram of water standard.  Why?

Karl Fischer Titrators count moisture in micrograms!

Since Karl Fischer Titrators count moisture in micrograms it's easier to think about the water standards in terms of micrograms.  Why?

We evaluate our water standard test in PPM

For the Hydyanal 1.0 we are looking for results within ±3% of 1,000PPM (970PPM to 1030PPM).  For the Hydranal 0.1 we are looking for results within ±10% of 100PPM (90PPM to 110PPM).

Don't forget this formula!:

PPM = WATER DETECTED IN MICROGRAMS/SAMPLE SIZE IN GRAMS

(For those who don't know PPM stands for Parts Per Million)

We hope this information has been helpful.

Titration

So you need to measure the amount of sodium chloride in your food products. While we have written about this topic previously in other posts and addressed some of the approaches used to test for % sodium chloride (including the use of hand-held salt meters) we have found that it is a more common practice to use an automatic titrator to accomplish this task.  In fact we think it is the preferred instrument and method of choice.  To be sure there are pros and cons to using different methods but we still find that titration is accepted as the primary method for getting the most accurate results.

How it's used

Although salt meters using the conductive method are faster (3 seconds vs. 2 to 3 mintues) and can be employed quickly in a production line process, titrators can also be implemented in the same testing environment with modest effort.  Additionally and regardless of how the tests were performed on the production line, titrators are generally put to work in the Quality Control/Quality Assurance Lab as a final check against periodic production line testing.

Supporting the use of titration as an accepted method includes some well known documented techniques including Mohr's and Volhard's methods making titration a recognized and trusted approach.

What's next...

Once you have made the decsion to use titration as the testing method it's just a matter of knowing:

• What items you need

• How to prep your sample

• How to setup the titrator

Luckily we have already thought about this and put together a list of 8 items your going to need.  We also created an application-note providing step-by-step instructions for you to follow to conduct a titration.

Many companies produce the foods we eat.  Do you ever wonder why or how they test for salt during the production process?

Salt which is made up of 40% sodium and 60% Chloride is an important ingredient found in food.  While salt can make food taste better, control color, and maintain food texture, it is also considered a health-risk factor (mostly due to the sodium).  Measuring and controlling the levels of salt between the extremes is a constant battle.  Producers of processed foods generally have the biggest need for identifying and controlling salt levels to address not only the taste, color, and texture of foods but also to address some of the healthier eating lifestyles more and more consumers are demanding.

For these reasons it is paramount that salt is measured accurately.  So how do we do that?

Food comes in a variety of forms.  Solid, Liquids, pastes, creams, pieces, chunks, wafers, crackers, gooey, sauces, liquids with chunks in them...let's see what else..Anyway, you get the idea.  There are a lot of ways food can be produced and consumed!

So what device or devices can we use to measure the salt found in these numerous forms of processed foods?

Well, there are a number of "salt meters" out there that can measure salt.  However, not all salt meters can measure the particular salt you are looking for in the same way.  In fact some "salt meters" can only measure salt under certain conditions and or in certain substances like water or sea water.  For this reason it is important to first consider what your going to be testing.  For example, If your food sample includes "food stuff particles" that you can grind into a paste form, then you can probably use a salt meter that utilizes the conductivity method.  On the other hand if you have a brine that you immerse food into and your only concerned with the liquid then perhaps a different salt meter will work.  

The point is this.  The form of the food at the instant you are going to perform the test is key.  Many types of foods can be formed into pastes and diluted with water.  If the food you need to test is like this then a simple salt meter utilizing the conductivity method may be able to perform the test to your satisfaction.  I say may because % salt levels and other accuracy factors may require that you use an entirely different method of titration known as silver nitrate titration instead.

Salt Meter vs. Titration?

A brief explanation and description of the two measurement approaches:

The Mohr method, also known as a silver nitrate titration method, utilizes the characteristics of silver nitrate that reacts with chloride ions to measure the salinity %. 

Conversley, some of the more popular salt meters emloy the electric conductivity method.  Both methods measure the salinity but operate on different measurement principles.  However, by creating a conversion table between the two testing methods, correlation between the set of results can be seen.

Aside from the measurement capabilities of each approach there are pros and cons to each.

While each method has benefits we have recently found through some informal surveying that some food processors are choosing to use both methods.  These companies are finding that it is easier to use the hand held devices and perform quick spot checks on the production line.  If any problems are identified on the production line then further verification and testing can be performed using the titration approach.  Some think using this collaborative approach is ideal.

ALSO READ OUR MOST RECENT UPDATES TO THIS BLOG POST : Salt related posts

Tensiometers are instruments used for conducting surface analysis on liquid substances.  Typical applications Tensiometers perform include measuring surface tension, interfacial tension as well as liquid density and Lamella Length on some Tensiometer models.  Some models can also perform other tasks including powder wettability and dynamic contact angle of a solid substrate.  Depending on the types of information the operator is seeking to find one model may be more appropriate than the other.

To help prospective users evaluate and compare the different types of models available in the market we have prepared a reference document we call the:

"Tensiometer Selection Matrix"

This matrix is not necessarily brand specific as it was designed to help those seeking to compare capabilities and prices among popular manual Tensiometer models vs. popular Automatic or "digital" Tensiometer models.

We hope you find the Tensiometer Selection Matrix helpful in your search and evaluation of Tensiometers.

YES IT CAN!

You can measure moisture in solid samples including plastics, powders, ores, gooey substances that are thick and viscous, greases, and many more.  The key is sample preparation to ensure that a uniform material will be tested.  Once those details are worked out the pattern for testing is the same every time. 

You hear a lot about people running traditional Karl Fischer titration using direct injection with a syringe and needle. That’s pretty easy. 

So how do you test for moisture in solids?

For more awkward samples like a solid or solid-like substance we can evaluate the moisture using a Karl Fischer Titrator with an Evaporator Oven.

Believe it or not that’s pretty easy too. I guess that’s why we wrote this post. We wanted to let readers know that the process for running a Karl Fischer moisture test using an evaporator oven is not that difficult.  As mentioned already the most difficult part is probably working with your sample. To help show how the process works we created this short 7 minute video detailing the steps along the way. Please make note that the instruments used for this demonstration are the Karl Fischer Titrator (MKC-610DT) and the Evaporator Oven (ADP-611).

Hope you enjoy.

In the video below we show the 600 series Karl Fischer Titrator.  Today we have additional models like the MKC-710 series that work with the ADP-611 solids evaporator.

We work with numerous titrator models and encounter many of the day-to-day problems associated with broken electrodes.  In many instances some of the electrodes are destroyed beyond repair but in other circumstances we find that some are in fact capable of being repaired. 

Most of our success with repairing or refurbishing electrodes is with Karl Fischer Generator Electrodes (also known as Inner Burettes). 

However, we do try to evaluate and determine whether other types of electrodes can be repaired also.  Generally we will ask for a photo or other description of the damaged electrode to determine if a repair is possible.  An example of how we examine a typical Karl Fischer Generator Electrode can be viewed in the following short video.  Take a look and let us know if we can help you.

On July 5th, 2008, a workplace rule designed to protect workers from outdoor heat exposure took effect in Washington State. This rule was passed on June 4 after six public hearings were conducted on heat stress and its causes. The hearings confirmed what officials already knew: working outside in hot weather is a health hazard.  The three requirements for employers with employees who work outside are to:

·  Train employees and supervisors to recognize heat-related illness and what to do if someone has symptoms.

·  On days when temperatures require preventive measures, increase the volume of water available to employees.

·  Have the ability to appropriately respond to any employee with symptoms of illness.

It's now 3 years later...would a handheld WBGT Meter be a helpful tool?...

The Wet Bulb Globe Temperature (WBGT Handheld meter) is a tool perfectly suited to helping Washington State employers comply with this new law. This hand-held tool is used to estimate the effect of temperature, humidity, and solar radiation on humans and determine appropriate exposure levels to high temperatures. A WBGT index is commonly used as a guide for environmental heat stress to prevent heat stroke during physical exercise or while at work. Based on the index shown, employers can estimate the probability that a heat-related illness with occur and provide the appropriate amount of water available for the current weather conditions. See a video demonstrating the use of the WBGT103 below.

For more information on the new Washington State law, go to: http://www.lni.wa.gov/safety/topics/atoz/heatstress/default.asp

Most operators who measure moisture using a Volumetric Karl Fischer Titrator tend to have difficulty in 3 areas.   Unlike Coulometric Karl Fischer Titrators where the equipment setup and reagents are fairly straight forward, Volumetric Karl Fischer Titrators differ greatly.  Understanding how a Volumetric Karl Fischer Titrator differs and how the equipment functions is not only paramount in terms of knowing how to operate the instrument it is critical if you want to obtain accurate and repeatable results.

8 out of 10 questions we receive usually fall into one of these 3 problem areas:

1. What REAGENTS should I use for testing my samples?  Titrants, Composites, Solvents?

2. "TITER VALUE" ..Who, What, Where, Why and How?

3. "SAMPLE SIZE" ..How much do I need or should I use? 

Although these 3 areas at first may seem problematic and unrelated they are not.  In this 9-minute presentation we will explain why the burette size matters, how to calculate a correct sample size and explain how the volumetric titrator reagent strengths work.  Tying all three areas together will hopefully not only clear up some of the mysteries surrounding Volumetric Karl Fischer Titration but also empower operators with choices for conducting tests under varied conditions.  And, oh yes, obtain accurate and repeatable results every time.    Important note:1 ppm = 0.001 mg/g; 1 mg/g = 1000 ppm.

In this presentation we discuss the basic Karl Fischer Water Standards and talk about some of their uses for both Coulometric and Volumetric Karl Fischer Titration.  We also describe some of the related problems that can be identified and overcome by using Karl Fischer Water Standards.

• Karl Fischer Water Standards
• Why we use them
• Coulometric Karl Fischer
• Volumetric Karl Fischer