# Different types of Moisture measurement Instruments

**URL:** <https://forumautomation.com/t/different-types-of-moisture-measurement-instruments/1658>\
**Category:** Analytical Instruments\
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**Created:** [January 14, 2017, 7:27am UTC](https://forumautomation.com/t/different-types-of-moisture-measurement-instruments/1658 "2017-01-14T07:27:27Z")\
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**Author:** ![denizen](https://forumautomation.com/letter_avatar_proxy/v4/letter/d/848f3c/32.png) [@denizen](https://forumautomation.com/u/denizen)\
**Post date:** [January 14, 2017, 7:27am UTC](https://forumautomation.com/t/different-types-of-moisture-measurement-instruments/1658/1 "2017-01-14T07:27:27Z")

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**Conductivity - Moisture measurement**

Measurement of how a specific material conducts electricity.

Can measure the capacitance,conductance or resistance of a material.

Water is a poor conductor.

The change of how a material reacts to electricity can be used to quantify the amount of water.

**Benefits of conductivity moisture measurement** Inexpensive Low power easy to use Portable

**Limitations of Conductivity moisture measurement**

Blind to changes in the chemical makeup of a solution. High maintenance:frequent replacement Detection limit of 30-40% of water content. Inaccurate measurement for samples with 4-6% of moisture Difference in sample density and temperature affect measurement

**Microwave - Moisture measurement**

Measurement of microwave energy.

Water is an excellent absorber in the microwave region.

Water absorption can be used to directly quantify water concentration.

**Benefits of Microwave moisture measurement**

Able to detect moisture at the surface and core of the product

Precise measurement within a small area.

sensors can be installed directly on the production line.

**Limitations of Microwave moisture measurement**

Needs dryer to operate

Mostly for conveyor belt,not during the process

Not applicable for liquids

Dependent on electrical permitivity of analyte

Can be limited by temperature

Analyzing time is greater than milliseconds

**Optical methods - Moisture measurement**

Optical analysis methods measure the emitted,absorbed/transmitted or reflected light from a sample.

Photometry - Measures the overall magnitude of the light intensity.

Spectroscopy - Spatially disperses the different wavelengths of light and and measures the intensity of the light at the discrete wavelength.

**Benefits of Photometry**

Smaller number of calibration Non destructive to the sample Tuned for a specific application can be used for solids,liquids and powders Low power easy to use Portable Cost can be lower than a spectrometer

**Limitations of Photometry**

They will not work for other applications that require different wavelengths unless modified. For applications only where chemistry does not change over time. Only 2-3 parameters can be measured. Need to be initially calibrated for analyte of interest.

**Benefits of Spectroscopy**

Monitor reaction process in real-time. Acquisition cost has come down to photometer levels with new technology offering. Extremely low cost of ownership. Can be used for solids,liquids and powders. Can be used for more complex chemistries. More measurement parameters can be added with software. Non-destructive to the sample. Measures in millisecond. Enhanced spectral processing. Built in chemometric modelling on latest technologies Low power Easy to use Portable

**Limitations of Spectroscopy** Instrument choice dependent on chemistry. Needs to be initially calibrated for analyte of interest.