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Frequently Asked Questions

Moisture Analyzers MS/MX/MF/ML

Question

Answer

General

What is the difference between MS/MX/MF/ML and Karl Fischer type analyzer? Top

1. MS/MX/MF/ML is a heating and drying method analyzer that compares weight before and after heating and drying, while a 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. MS/MX/MF/ML is very easy to handle, needs short time to measure and is reasonably priced.
3. Where required resolution is under 0.01% MS/MX is more suitable in terms of handling, accuracy and running cost. There is no difference between data obtained with the Karl Fischer method and heating and drying method; however MS/MX is more likely to have better repeatability than a Karl Fischer type..

Accuracy

What does 0.01%, 0.02%, 0.05% and 0.1% of accuracy mean? Top

These are the variation and repeatability of moisture content rate data where more than 5g of the same sample is tested repeatedly under the same conditions. In statistics it is called standard deviation.

Samples

What is the reagent, Sodium Tartrate Dihydrate like and when is it needed? Top

Sodium Tartrate Dihydrate is suitable for testing a moisture analyzer itself since its moisture content rate is deemed theoretically. Sodium Tartrate Dihydrate is Sodium Tartrate 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 MS/MX and optional accessory of MF/ML (30g x 12pcs).

Why isn’t the result of 15.66 obtained? Top

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 to the sample in a mechanical fashion. Ambient moisture that is 0.09% can adhere to most samples. Also, moisture and/or impurities left on a pan, accidental errors during measurement, or a combination of both can cause the result to vary between 15.0 and 16.0% in actual measurement.
2. If the difference between the actual result and 15.66 is large it is concluded that heating temperature may be too low. When Sodium Tartrate Dihydrate is tested, the accuracy of measurement of MS/MX/MF/ML should be set to MID of Standard Mode, with heating temperature of 160C; after pre-heating for 8 minutes, 5g of the sample should be placed on evenly on the pan.

Is Sodium Tartrate Dihydrate safe? Are there any special procedures for handling it? Top

1. It is perfectly harmless. Sodium Tartrate Dihydrate is used as a flavoring for foods and thus, if eaten it is a safe material, unless more than 218g is ingested (a fatal dose for someone with a body weight of 50 kg). However if it gets on mucosa (i.e. in eyes or up the nose) it should be washed out immediately.
2. The material does not require special treatment for disposal. It can be disposed of as ordinary burnable waste.

Can Sodium Tartrate Dihydrate be recycled? Top

No. Moisture once decomposed from crystal of the sample by heat cannot be reconstituted.

Can any material be tested with the analyzer? Top

1. Materials that are explosive and/or flammable and/or emit fumes when heated are not suitable to be tested by heating and drying method. Those materials must not be tested with the analyzer.
2. Materials whose surface gets dried first and forms a membrane that makes pressure inside high must not be 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.

What is the minimum weight at which moisture content rate can be measured? Top

In the case of using MS/MX/MF/ML, a sample of more than 0.1g is measurable. The sample mark on the display will light up when sample amount is enough.

What is maximum weight at which moisture content can be measured? Top

In the case of using MX/MF/ML, samples of less than 51g are measurable. “E” will be displayed if the sample is over 51g. MS-70 can measure samples of up to 71g.

Is it true that the more sample used, the more accurate the measurement will be? Top

No, that is not true. An excess amount of a sample may not get heated inside evenly, or heating time may take too long. In such cases measurement may not have a high repeatability.

Does the way in which a sample such as powder is placed on a pan affect the measurement result? Top

Yes. The way a sample is placed on the pan determines heat distribution. To measure moisture content rate accurately, even heating and vaporization are needed so the sample should be flat on the pan.

How do you measure samples with low moisture content? Top

Due to the heating measurement method, a larger sample size gives better measurement repeatability, and it is better to crush it into small pieces.

How much sample weight is required to measure the PET? Top

More than 10g of sample size may give a similar measurement result to the Karl Fischer method when measured by MS/MX.

Calibration

Is calibration of the moisture analyzer, MS/MX/MF/ML, with Sodium Tartrate Dihydrate possible? Top

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.

Can a user perform weight and temperature calibration? Top

Yes (only MS/MX can carry out temperature calibration at 100 and 160 deg. Celsius). Also, the results of these calibrations can be printed out in accordance with GLP, GMP or ISO. 1. For weight calibration the optional accessory calibration mass, 20g, AX-MX-41 is recommended. 2. Use optional accessory temperature calibrator, AX-MX-43, with certification for temperature calibration.

Are traceability system diagram and certificate of measurement available? Top

Yes both are available upon request.
1. If it is of the analyzer itself, the certificate covers weight and temperature.
2. If it is of the calibrator, the certificate only covers temperature calibration; however, the calibrator is sold with a tracability certificate and certificate of measurement provided free of charge.

Miscellaneous

Should I consider moisture in a glass fiber sheet when it is used? Top

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.

Is absolute measurement of moisture content rate possible? (Can only water content be measured?) Top

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 MS/MX/MF/ML? Top

Heating value per unit of time is higher than with other heating methods, and its useful lifetime is longer. For these reasons a halogen lamp was chosen. And thus, moisture analyzers with halogen lamp can shorten measurement time taken. A halogen lamp emits much more light than other lamps, which is also beneficial when observing the sample while heating.

What is difference between halogen and infrared lamp? How do they relate to each other? Top

A halogen lamp emits 95 % of light that is within infrared wavelength field and its energy characteristic is basically the same as with infrared lamps.

How fast can moisture analyzer with halogen lamp heat up? Top

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.

What is SRA filter like? Top

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

How long is the halogen lamp life? Top

The halogen lamp will last for more than 5000 hours and is replaceable with AX-MX-34-120V/-240V.

What is the heating pattern? Top

The heating pattern is selectable from Standard Heating, Quick Heating, Step Heating and Ramp Heating for MS/MX/MF and Standard Heating and Quick Heating for ML.

Measurement

What is the benefit of being able to see inside of the analyzer while heating? Top

Being able to see inside the analyzer gives users a sense of safety. It is not only water in a sample that can be overheated or is burnable and may be vaporized, but also other materials 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.

What is the minimum measurement time? Top

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

Are temperatures of sample and displayed one the same? Top

The displayed temperature is the temperature of right on the pan; that is, of the sample especially when spread on the pan evenly. However, when the sample is placed unevenly or has a hard skin membrane the temperature is of the surface of the sample.
MS/MX/MF/ML does not have a sensor right on the pan but calculates the place where the temperature is assumed to be the one of that on the pan, and puts the sensor there. Temperature calibration is possible by users.

Why is the moisture content rate MS/MX/MF/ML measured less than that which FD-620 measured, and does the former take shorter time to measure? Top

1. With FD-620, the temperature displayed is lower than the actual temperature, and therefore it heats in a shorter time and the value can be lower.
2. MS/MX/MF/ML is an improvement over FD-620 in the sense of sensing the temperature of the pan. That is, the displayed temperature is assumed to be that of the one on the pan. To get the same result from a sample lessen the sample by 1g and set complete condition to HI.

What is highly accurate SHS like? Top

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

Why do the pans need two handles? Top

When measurement is required repeatedly hot, the same sample pan should not be used, since as soon as the new sample is put on the hot pan the moisture would start vaporizing, which would in turn make the measurement data inaccurate. To avoid this 2 pans and handles should utilized in turns, which not only enhances measurement repeatability and credibility but also prevents mishaps like burns.

What is the measurement mode? Top

Measurement mode is selectable from Standard Mode, Automatic Mode, Quick Mode, Timer Mode and Manual Mode to meet your application needs.

Is there a good way to decide what to set as the heating temperature for the sample? Top

WinCT-Moisture software is the solution to this problem. WinCT-Moisture utilizes the Optimum Temperature Search program RS-Temp that has 6 different heating temperatures for same heating time to offer the “Judgment” of A, B, C, D, E and F criteria, so the user may find out the optimum heating temperature for the sample quickly with just one test measurement.

Data Analysis

Can soybeans or coffee beans be tested as they are? Top

NO. Usually samples like peas should first be crushed in blender or mill because the temperature of the surface and inside can be very different. When crushed the sample can be heated evenly. Note that when crushing a sample, start the measurement soon because with crushing the sample’s superficial area increases and can absorb moisture from the ambient air.

Can materials like milk or colloids be tested? Top

Colloids are materials such as solid particles floating on water in milk or colloids that have surface tension and often become dotted. In such cases, let an optional accessory *glass fiber sheet absorb the sample. This improves the repeatability rate and shortens the time taken by one third to a half. Note that the weight of the glass fiber sheet should be tared. AX-MX-32-1/-2.

How should I measure vegetables, seaweeds and mushrooms? Top

The sample should be typical part of it. The part tested should be taken into consideration when samples have many parts such as vegetables and so forth.

How do you monitor the change of moisture contents? Top

The WinCT-Moisture software has RS-Fig software to collect the measurement data and show it graphically on a display, to show in an easy to understand format the change in moisture contents against the time lapse.

How do you compare measurements? Top

The RS-Fig software of WinCT-Moisture can show the measurements on 10 different color lines and the Statistics function gives Maximum, Minimum, Average, SD and CV.

How do you save the measurement data? Top

When you transmit the measurement data to a PC with the WinCT-Moisture software, it is easy to save the data as a “CSV” file. This “CSV” data file can be easily sent by e-mail and opened with the WinCT-Moisture software again.

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