A&D Weighing, an ISO 9001 certified company, designs and manufactures a complete line of electronic balances, scales, viscometers, moisture analyzers, weighing indicators and controllers.

MX FAQ

Frequently Asked Questions

Moisture Analyzers MX50/MF50

Question

General

  • What is the difference between MX/MF and Karl Fischer type analyzer?


Accuracy

  • What does 0.02% of accuracy mean?

Samples

  • What is the reagent, Sodium Tartrate Dihydrate like and when is it needed?
  • Why isn’t the result of 15.66 obtained?
  • Is Sodium Tartrate Dihydrate safe?
  • Is there any special process to handle?
  • Can Sodium Tartrate Dihydrate be recycled?
  • Can anything be tested with the analyzer?
  • What is minimum weight moisture content rate measured at?
  • What is maximum weight moisture content measured at?
  • Is it true that the more sample the more accurate the measurement will be?
  • Does how to place sample such as powder on a pan affect measurement result?

Calibration

  • Can calibration of the moisture analyzer, MX/MF with Sodium Tartrate Dihydrate be possible?
  • Can a user do weight and temperature calibration?
  • Are traceability system diagram and certificate of measurement available?

Others

  • Should I consider moisture in a glass fiber sheet when it is used?
  • Is absolute measurement of moisture content rate possible? (Can only water content be measured?)

Heating Method

  • What is the benefit of halogen lamp incorporated in MX/MF?
  • What is difference between halogen and infrared lamp?
  • How do they relate to each other?
  • How fast can moisture analyzer with halogen lamp heat up?
  • What is SRA filter like?

Measurement

  • What is the benefit of being able to see inside of the analyzer while heating?
  • What is the minimum measurement time?
  • Are temperatures of sample and displayed one the same?
  • Why moisture content rate MX/MF measured is less than what FD-620 measured and does the former take shorter time to measure?
  • What is highly accurate SHS like?
  • Why do the pans need two handles?

Data Analysis

  • Can soybeans or coffee beans be tested as they are?
  • Can materials like milk or colloids be tested?
  • How should I measure vegetables, seaweeds and mushrooms?

Answer

General

  • What is the difference between MX/MF and Karl Fischer type analyzer?
    1. MX/MF is a heating and drying method analyzer that compares weight before and after heating and drying while Karl Fischer type analyzer titrates KF reagent that contains iodine to sample electric-chemically.
    2. Karl Fischer method enables a measurement from some ppm to 100% (water) but operation is complicated and the unit is expensive. MX/MF is very easy to handle, needs short time to measure and is reasonably priced.
    3. Where required resolution is under 0.01% MX/MF is more suitable in handling, accuracy and running cost. There is no difference between data obtained with Karl Fischer method and Heating and drying method however rather MX/MF is likely to have better repeatability than Karl Fischer type.

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Accuracy

  • What does 0.02% of accuracy mean?
    • It’s the variation and repeatability of moisture content rate data where same sample is tested with the same conditions repeatedly. In statistics it is called standard deviation.

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Samples

  • What is the reagent, Sodium Tartrate Dihydrate like and when is it needed?
    • It is suitable for testing a moisture analyzer itself since its moisture content rate is deemed theoretically. Sodium Tartrate Dihydrate is what Sodium Tartrate is when chemically bonded to two water molecules or crystal water and becomes Sodium Tartrate again by releasing the water molecules when heated. Its moisture content rate is the ratio of the two water molecules, that is 36.031/230.082=15.66%. This sample is a standard accessory of MX and optional accessory of MF (30g x 12pcs).

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  • Why isn’t the result of 15.66 obtained?
    1. Moisture bonded inside of the material as crystal water is theoretically 15.66% however ambience has 10%RH ~ 90%RH moisture, which can adhere the sample in a mechanical fashion. Moisture that is 0.09% at the most of sample can adhere. Also, moisture and/or impurities left on a pan, measurement accidental errors, and combined of both can be the reason and the result may vary between 15.0 and 16.0% in actual measurement.
    2. If the difference between the actual result and 15.66 is big it is concluded that heating temperature may be too low. When Sodium Tartrate Dihydrate is tested accuracy of measurement of MX/MF-50 should be set MID, heating temperature, 160C and after pre-heating for 8 minutes 5g of the sample be placed on a pan evenly.

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  • Is Sodium Tartrate Dihydrate safe? Is there any special process to handle?
    • It is perfectly harmless. Sodium Tartrate Dihydrate is used as a flavoring to foods and thus, if eaten, unless it is more than 218g which is a fatal dose, it is a safe material.
    • However if it gets on mucosa (In eyes and nose) it should be washed immediately.
      There should be no special treatment to the material even when disposed. It can be disposed of as a burnable waste.

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  • Can Sodium Tartrate Dihydrate be recycled?
    • No. Moisture once decomposed from crystal of the sample by heat cannot be reconstituted.

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  • Can anything be tested with the analyzer?
    1. Material that is explosive and/or flammable or fumes when heated are not suitable to be tested by heating and dryingmethod. Those materials must not be tested with the analyzer.
    2. Materials whose surface gets dried first and makes a membrane which makes pressure inside high must not tested because they may be dangerous.
    3. Materials whose characteristics are unknown can be 1 or 2 as above and thus, should not be tested.

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  • What is minimum weight moisture content rate measured at?
    • In the case of using MX/MF-50, sample more than 0.1g is measurable. Sample mark on LCD display will light when sample amount is enough.

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  • What is maximum weight moisture content measured at?
    • In the case of using MX/MF-50, sample less than 50g is measurable. “E” will be displayed if sample is over 50g.

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  • Is it true that the more sample the more accurate the measurement will be?
    • No, that’s not true. Excess of a sample may not get heated inside evenly or heating time may be long. In such cases measurement may be not with high repeatability.

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  • Does how to place sample such as powder on a pan affect measurement result?
    • Yes. How to put a sample on a pan determines heat distribution. To measure moisture content rate accurately even heating and vaporization are needed so sample should be flat on a pan.

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Calibration

  • Can calibration of the moisture analyzer, MX/MF with Sodium Tartrate Dihydrate be possible?
    • No. However accuracy check can be done with the sample since moisture content rate of the sample is theoretically fixed. Heating and drying method moisture analyzer weighs sample before and after heating and weight and temperature calibration is possible.

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  • Can a user do weight and temperature calibration?
    • Yes (only MX can do temperature calibration). Also, results of these calibrations can be printed out in accordance with GLP, GMP or ISO.
      1. For weight calibration optional accessory calibration mass, 20g, AX-MX-41 is recommended.
      2. Use optional accessory temperature calibrator, AX-MX-43, with certificate for temperature calibration.

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  • Are traceability system diagram and certificate of measurement available?
    • Yes both are available upon request.
      1. If it is of analyzer itself, certificate both covers weight and temperature.
      2. If it is of calibrator, certificate is only about temperature calibration however the calibrator is sold with tracability certificate and certificate of measurement for free of charge, so no additional charge is not needed.

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Others

  • Should I consider moisture in a glass fiber sheet when it is used?
    • You don’t usually have to. However if you want to be very strict and remove moisture in a sheet dry and the sheet and store it in a desiccator prior to use.

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  • Is absolute measurement of moisture content rate possible? (Can only water content be measured?)
    • No. Minerals such as metal, glass or sand have only water as moisture content however most samples that is organic matter, depending on temperature, have other materials than water that can vaporize. Also, measurement results depend on heating temperature.


Heating Method

  • What is the benefit of halogen lamp incorporated in MX/MF?
    • Heating value per unit of time is higher than other heating method and its useful lifetime is longer for which reasons halogen lamp was chosen. And thus, moisture analyzers with halogen lamp can shorten measurement time taken. Halogen lamp emits much more light than other lamps, which is also beneficial when observing the sample while heating.

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  • What is difference between halogen and infrared lamp? How do they relate to each other?
    • A halogen lamp emits 95 % of light that is within infrared wavelength field and its energy characteristic is basically the same as with infrared lampsr.

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  • How fast can moisture analyzer with halogen lamp heat up?
    • It can heat up the pan up to 200C from the ambient temperature within 2 minutes, much faster than by infrared or sheathed heater method.

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  • What is SRA filter like?
    • SRA stands for Secondary Radiation Assist and is an innovative heating method A&D developed for the MX/MF moisture analyzer. The old method where halogen lamp directly heats sample on a pan, cannot heat the sample evenly because of the difference of the varying distance between the lamp and the sample. SRA improve on this and can heat the sample up evenly with the secondary radiated heat by the glass placed under the lamp, which is placed there in order to emit even heat down to the sample. (Patent pending).

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Measurement

  • What is the benefit of being able to see inside of the analyzer while heating?
    • Being able to see inside of the analyzer gives users a sense of safety. Not only water in a sample that can be overheated or is burnable may be vaporized but also other material can be carbonized or decomposed. It is very important for users to check by looking at the sample through Progress Window to evaluate the data.

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  • What is the minimum measurement time?
    • It depends on material and moisture content but because MX/MF incorporates 400W halogen lamp as heating source the pan can be heated from ambient temperature to 200C in only 2 minutes. Also, since a SHSTM sensor designed for analytical balances is installed sensing weight of sample before and after heating is precise and thus, requires less sample volume than before. With appropriate heating temperature and sample mass, measurement can generally be done within a few minutes to 20 minutes. Therefore, for the following reasons MX/MF’s heating time and thus, measurement time are shortened.
      1. Heating to a set temperature is fast
      2. Only very little quantity of sample is needed to measure.

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  • Are temperatures of sample and displayed one the same?
    • Displayed temperature is the one of right on the pan, that is, of sample especially when spread on the pan evenly. However when placed unevenly or it has hard skin membrane the temperature is of the surface of the sample. MX/MF does not have the sensor right on the pan but calculates the place whose temperature is assumed to be the one of on the pan and puts the sensor there. Temperature calibration is possible by users.

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  • Why moisture content rate MX/MF measured is less than what FD-620 measured and does the former take shorter time to measure?
    1. With FD-620, temperature displayed is lower than the actual and thus, it heats shorter and value can be lower.
    2. MX/MF is an improvement over FD-620 in the sense of sensing temperature of the pan. That is, displayed temperature is assumed to be the one of on the pan. To get the same result from a sample lessen by 1g and set complete condition at HI.

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  • What is highly accurate SHS like?
    • SHS stands for Super Hybrid Sensor and is weight sensor that A&D innovated to enable high speed weighing within 1 second and suitable for analytical balances requiring high resolution and accuracy. SHS incorporated in the MX/MF moisture analyzer enables the analyzer to capture the dynamic weight and thus, to measure moisture content in shorter length of time. (Patent pending).

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  • Why do the pans need two handles?
    • When measurement is required repeatedly hot a sample pan should not be used since once the new sample is put on the hot pan moisture would vaporize, which makes measurement data inaccurate. To avoid this 2 pans and handles should utilized in turns, which not only enhances measurement repeatability and credibility but also prevent mishaps like burns.

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Data Analysis

  • Can soybeans or coffee beans be tested as they are?
    • NO. Usually samples like peas should first be crushed in blender or mill because temperature of surface and inside can be very much different, plus when crushed can be heated evenly. Note that when crushing sample start measurement soon because by crushing the sample’s superficial area gets bigger and can absorb moisture in the ambient air.

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  • Can materials like milk or colloids be tested?
    • Colloids such as solid particles floating on water in milk or colloids that has surface tension and often becomes dotted. In this cases let an optional accessory *glass fiber sheet absorb the sample. This improves repeatability rate and shortens time taken from one third to a half. Note that tare the weight of the glass fiber sheet. AX-MX-32.

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  • How should I measure vegetables, seaweeds and mushrooms?
    • Sample should be typical part of it. Part tested should be considered when samples have many parts such as vegetables and so forth.

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