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Frequently Asked Questions
Moisture Analyzers MS/MX/MF/ML
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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?
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?
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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