Moisture Analysis: What is a Moisture Analyzer?

What is a Moisture Analyzer?

Let’s start out by explaining why you may need a moisture analyzer. 

Title 21 of the Code of Federal Regulations section n explains “Safe-moisture level is a level of moisture low enough to prevent the growth of undesirable microorganisms in the finished product under the intended conditions of manufacturing, storage, and distribution.

“The maximum safe moisture level for a food is based on its water activity (aw). An aw will be considered safe for a food if adequate data are available that demonstrate that the food at or below the given aw will not support the growth of undesirable microorganisms.”

The Role of the Moisture Analyzer

Moisture analyzers are widely used in meeting these standards.  They go far beyond the food industry – affecting such diverse products as pharmaceuticals, plastics, paint, wood, birdseed, soybeans, fertilizer, cement, detergent, shampoo…etc.

A Moisture Analyzer Measures More than Water Activity

While Title 21 … Read the rest

Moisture Balance Ideal for QC in Molding Plastics

Moisture Balance Ideal for QC in Molding Plastics

Operators of extrusion molding, injection molding, thermoforming and related equipment must pay particular attention to resin moisture content because too much or too little moisture will impact the quality of molded products.  Correct moisture content depends on the resins being used and is specified by plastic resin manufacturers.    

Resin manufacturers may ship product at the correct moisture content but equipment operators should take steps to ensure ambient conditions at the plant do not raise or lower the content prior to processing.  Two important steps in quality control are proper resin storage and using commercial drying ovens.  Periodic checks with a benchtop moisture analyzer programmed for plastic resins provide assurances that moisture content is on target, or otherwise call for pre-processing adjustments.

The Benchtop DSC 71P Lab Moisture Analyzer for Quality Control

Operating on the LOD (loss of weight on drying) process it handles samples to 71 grams and delivers … Read the rest

How to Select a Moisture Analyzer for Low-Moisture Plastic Resins

DSC 71P Moisture Analyzer
DSC 71P Moisture Analyzer

When you select a moisture analyzer for low-moisture plastic resins you will need a model that that not only can quickly but also accurately gauge the moisture content of these resins.   And as with many quality control requirements that involve moisture content, you’ll want a moisture balance that can meet standards set by trade associations and professional organizations.

In this post you’ll get a briefing on the following:

  • why low moisture content is important in plastic resins
  • a technical standard that applies to determining moisture in plastics
  • how benchtop moisture analyzers work
  • a standards-compliant moisture analyzer
    for plastic resins

Why Low Moisture Content is  Important

Owners of injection molding companies and operators of injection molding machines are aware that incorrect moisture content in plastic resins can result in an inferior finished product.

Product shipped from resin suppliers may have the specified moisture content but ambient conditions … Read the rest

Moisture Analysis – A Close-up Look

Moisture Analysis - What You Need to Know

Moisture content is an important quality control criterion across the board and relates to establishing or conforming to specified levels of moisture in a product.  Correct moisture levels are established by government, trade and professional organizations and relate to the percentage of water and other liquids in a product.  Therefore, moisture analysis, can be viewed as first establishing recommended moisture content then checking to confirm that products meet the criterion during and after processing prior to packaging.

All of us experience the impact of incorrect moisture content.  Salt and sugar, for example, absorb moisture from the air and cake up.  Crispy potato chips quickly get gummy on humid picnic days.  Portland cement will turn into a block if left unsealed in the garage.

On the other side, when you buy a product by weight you don’t want to pay for excess water.  If water is intentionally added to a product … Read the rest

Stability Testing for Temperature and Humidity

Stability Testing for Temperature and Humidity

Stability testing is a critical part of drug and medicinal product development to determine the shelf life of such products under a variety of environmental conditions such as temperature and humidity.  Family prescriptions likely have on their label a recommended “use by” date and notification if special storage conditions should be observed. The regulatory mandate for stability testing in the United States is contained in 21 CFR Part 211 Section 166.

Tests to determine storage requirements and shelf life for drugs and other medicinal products are taken under a variety of imposed and tightly controlled environmental conditions.  Because testing time can be extensive accelerated studies are permitted to support tentative expiration dates provided full shelf life studies are being conducted.


Temperature and Humidity Test Chamber Specs

Stability testing is performed in specially designed test chambers capable of duplicating a broad range of temperature … Read the rest

Environmental Test Chamber Series with Ultrasonic Humidifiers

A new series of environmental test chambers now available from Tovatech in 4 storage capacities from 24 to 80 cubic feet feature ultrasonic humidifiers producing far smaller water particles than centrifugal humidifiers.  The ultrasonic humidifiers are placed above rather than inside storage cabinets thereby freeing space for additional test specimens.   Dehumidification is handled by a separate latent coil.  Both systems are operated by a programmable logic microprocessor controller.

The ultrasonic humidifiers require water with low mineral content delivered at 10 to 60 psi.  As a means of conserving this water an optional purification system for tap water is available.  Connected to the temperature humidity stability test chamber it continuously recycles used water drawn from the unit’s pluggable interior drain.

The system delivers a humidity variation of ±3% in the humidity controlled temperature range between 10⁰ and 70⁰C.

Precise temperature control at ± 0.5⁰C from 4⁰ to 70⁰C is also supported … Read the rest

A Moisture Analyzer for Shampoo Quality Control

Most everyone has their favorite shampoo and probably pays little attention to what’s inside the tube or bottle – only that it does a good job cleaning hair.  Chances are the thickness of the shampoo is important as well – cheaper brands that are thin and watery usually don’t pass muster.  Yet water, specifically deionized water – comprises about 70 to 80% of the shampoo formulation with the actual target specified by the manufacturer.  Keeping formulations on target is eased with a moisture analyzer for shampoo quality control.

While formulations vary, the approximately 25% non-water contents of shampoo include detergents and surfactants, foam boosters, thickeners and conditioners.  Preservatives and modifiers, fragrances and dyes are typically added to the batch then mixed.  After the mixing period samples are sent to the quality control lab.  Among other tests QC personnel can use a moisture analyzer to determine that the water content is … Read the rest

Avoid Moisture Analyzer Weighing Errors

Procedures to avoid moisture analyzer weighing errors start from the time you unpack your equipment.  Of course you will read the instructions in the operating manual, right?  But here’s a brief rundown of points to keep in mind from the beginning.

Proper Moisture Analyzer Setup

These are sensitive instruments, of that there is no doubt.  And it does not take much to throw them off.  Like the real estate business, the key is location.

A correctly assembled moisture balance should be in a location free of drafts, temperature and humidity fluctuations, vapors, dust, and vibration caused by moving equipment in the area or by jarring the table on which the unit is placed.   Proximity to magnetic fields or equipment that generates them must be avoided.

Allow enough elbow room so that operators can work comfortably when performing moisture analysis.

Confirm that the moisture analyzer is level using the foot screws … Read the rest

Selecting a Moisture Analyzer Drying Process

Infrared moisture analyzers such as the new Kern MLS-C now available from Tovatech use the thermogravimetric drying process to calculate the moisture content of a sample.  Also called the loss of weight on drying (LOD) method, the drying process compares the weight of a sample after drying to the weight before drying.  The difference is displayed the percent of moisture in the sample.  This is a critical quality control step to confirm that commercial bulk drying ovens are performing to specification and that the product meets regulatory or industry standards for moisture content.

Selecting the Moisture Balance Drying Mode

Because products react differently to heat employed during the drying process, laboratory moisture balances can be programmed for different drying modes or drying profiles.  These can be classified as standard, rapid, step and gentle. The mode is graphically displayed on the control panel. Here is a general description of each:

  • Standard
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Filter Cake Moisture Analysis

This document looks at large scale moisture analysis and control for filter cake and green ball moisture. The same principle as your typical laboratory moisture analyzer is followed but on a scale that supports large automated operations.  The initial part of the project focused on developing a fully automated filter cake drying system. Samples of up to 2 kilograms could be analyzed to a ‘2 sigma accuracy of 0.02% moisture’. Subsequently the operators desired ‘a more automated on-line filter cake moisture analysis system. As of the document’s writing it is in the design stage.  In the new design filter cake samples will be diverted off production conveyor belts and tested for moisture in a dynamic weighing, drying, reweighing rig.

For further information visit… Read the rest