As we discussed in our previous blog post, analytical testing verifies product quality and formulation safety. It also ensures the formulation prepared at benchtop scales as needed to pilot plant volumes and to commercial production. Our team excels at creating the formula at benchtop, as well as working with existing lab-scale formulations, and deploying critical analytical testing through scale-up to commercial production so the formulation performs at large scale with expected results. In our third post about analytical testing, we’ll review the types of tests to consider when developing and scaling up chemical or biological products. (Also check out our first blog post in this series, “What is analytical testing?”)
When deciding which analytical tests to run, there are a few questions to consider.
- What type of formulation is it?
- What are your goals or objectives for running analytical testing? In other words, what do you hope to better understand or validate about the product?
- How are you going to use the results?
When you initiate an analytical testing project with us, our analytical chemists will discuss these and other more specific questions with you to ensure our workplan aligns with your needed outcomes. It is also common for our customers to provide us with a list of tests to run.
While there are different ways to classify the types of analytical tests, we like to divide them between wet chemistry and dry chemistry, which is why the answer to the first question above is important. Several specific tests do overlap wet and dry, but there are several that have different parameters. We’ll take a look at the various tests below, as well as touch on stability testing, a specialty of ours.
Wet Chemistry
Products evaluated under our wet chemistry category are liquid formulation types and include:
- Suspension Concentrates (SC)
- Oil Dispersion
- Soluble Liquids
- Emulsifiable Concentrates (EC)
- Stabilized Emulsions
- Suspo-emulsions
Some of the tests we perform can be more specific to the formulation type, while others are standard practice across liquid formulations.
Appearance test: Customers will provide us with the appearance specifications for the product, which we use as comparison to our visual assessment. The appearance test is often the first test run and provides an initial check for any issues with the product. It typically examines properties like:
- Color: Does the color we see match the description the customer provided?
- Clarity: Is the solution clear or cloudy?
- Opalescence: Is light able to pass through it?
- Particulate matter: Are there any foreign particles or clumps present?
Assay test: The assay test is important in verifying the active ingredient content and that it is within the set range. We have a variety of equipment to prep and run the test, including centrifuge, high pressure liquid chromatography (HPLC), gas chromatography (GC) and titration.
Density test: We use a densitometer to provide the specific gravity metric, then we use a formula to convert it to the density. If the product has a lot of air bubbles in it, we’ll use a centrifuge to force the air to the top so we can get an accurate gravity reading on the densitometer.
pH test: We use a pH meter to measure the pH level of a product. The pH level can impact how quickly the active ingredient degrades. It can also cause the product to fall out of solution.
Viscosity test: When the viscosity of a product is too low, the product will separate out; if it’s too thick, it becomes difficult to dilute or mix in the spray tank, can clog application equipment and can lead to uneven deposition on the spray target.
Suspensibility test: This test analyzes how well the active ingredient is suspended within the product. Suspensibility can be connected to viscosity, too, because if the product is less viscous, it could separate and lead to packing.
Particle size test: Particle size is closely tied to wet sieve testing. The particle size must be within specification to avoid issues during mixing and applying the product.
Wet sieve test: The wet sieve test simulates how the product would flow through a spray nozzle and is closely tied to particle size testing. If the particle size is too large for the recommended application nozzle, it will not flow as desired, causing clogged nozzles and reducing coverage during application.
Spontaneity of dispersion test: This test is typically specific to SC formulations and assesses how quickly they disperse within water when diluted.
Flashpoint test: This test is necessary to determine a product’s flammability. The flashpoint, or lowest temperature at which a product’s vapors can ignite when exposed to a flame or spark, impacts manufacturing, transportation, storage and disposal parameters.
Water content test: This test uses a Karl Fischer test to determine water content within the formulation. When testing EC formulations, we do not want water present.
Pour test: This tests how much of the product comes out of the container.
Packing test: This is a less common test but will assess if there are issues with the product settling.
Dry Chemistry
Dry chemistry evaluates dry or solid formulation types, which include:
- Dry Flowables or Water-Dispersible Granules
- Wettable Powders
- Extruded Granules
- Impregnated Granules
- Baits
Dry chemistry testing involves similar tests as wet chemistry with some variations to what the test is assessing, which we’ll explain below.
Appearance test: When evaluating the appearance of dry or solid products, we’re looking at the physical dimensions, form and uniformity of the particles, as well as the color and whether there are foreign particles or clumps present.
Assay test: To run the assay test in dry chemistry, we crush down the product using equipment most appropriate for the product type. It may be a mortar and pestle, a riffle or a blender.
Wetting time test: This tests how long it takes the product to become fully wet when added to water. We place the product on top of water in a beaker and time how long it takes to fully fall down into the beaker.
Bulk density test: To determine the bulk density metric, we first calculate the loose density by weighing the product in a graduated cylinder. We then pack it down and calculate the tamped density.
Water content test: Testing for water content may involve a moisture balance test, or we can use the Karl Fischer test.
Dispersibility test: This test assesses how uniformly a dry product is dispersed and how well it remains suspended in water.
Dry sieve: This is similar to the wet sieve in wet chemistry but without water, and it is one way to test the dustiness of the product. Dry sieve measures how much dust goes through the screen. We can also conduct wet sieve on dry products.
These tests are run the same way whether it’s wet or dry chemistry:
- pH test
- Suspensibility test
- Particle size test
Stability Testing
The above analytical tests are key indicators of the current state of a product, but what happens when that product is in storage for an extended period of time? How long can it be stored and still remain effective? That’s where stability testing comes into play. It evaluates all the same variables as the tests above, but under specific conditions that simulate the passing of up to two years. How? We’ll dig into that in our next blog post!
Connect with CJB Applied Technologies for your analytical testing needs
For companies with a deep R&D pipeline or limited staffing expertise, completing the necessary analytical testing can be a challenge. Our team is backed by decades of analytical and formulation experience to help companies fill their testing capacity gaps. In addition, our pilot plant team supports your scale-up needs through commercialization, and if you are experiencing production capacity constraints, they can seamlessly transition your product to our sister company CJB Industries for commercial production.
Are you creating synthetic or biological products and need analytical testing support, such as stability testing, clean out validation, retain evaluation and more? Contact us today. You can tap into any of our services independently of the others – product development, analytical testing, method development, scale up and commercialization needs.
Also, be sure to check back soon or follow us on LinkedIn as we dig into stability testing and how to develop analytical methods.
