Moisture analyzer 6/22 LECTURE NOTES

Moisture AnalyzerLABORATORY POST-LAB

KERN MLB

• Moisture analyzer that provides direct reading of weight of sample and percent moisture.

Features of KERN MLB

• Controlled drying process with 1 halogen quartz heaters

• Heating from 50-160°C in steps up to 1°C• Terminates drying when weight is constant

or after fixed time period• Displays last measured value till replaced

by new measurement• Data can be printed or saved to PC via

RS-232 interface

Features of KERN MLB

• Quick calibration with external weights• Optional temperature calibration set: sensor and

display device• 3 LED displays: temperature, drying status, drying

time• Ambient conditions: 15°C - 35°C, max. 80% air

humidity; not condensing• Balance contains memory for automatic sequence of

20 complete drying processes• 4 programmable heating profiles: standard, fast,

staged (freely selectable time / temperature stages), and soft

Technical Specifications of KERN MLBRead Out -0.001g or 0.01%Max Sample Weight -50 gReproducibility with 2g sample

-0.5%Reproducibility with 10g sample

-0.02%Heater Type halogen Heaters -1 x 400WTemp. Range ºC -50C-160C

Parts of the KERN MLB

1. LCD DISPLAY

2. KEYPAD

3. VENTILATION DOME

4. HOOD HANDLE

5. HEATER HOOD

Uses of the Moisture analyzer

• Plastic moisture analyzer

• Trace moisture analyzer

• Food moisture analyzer

• Wood moisture analyze

How to Operate the Moisture analyzer• See Procedural Manual

Answers to Questions

1. Discuss Moisture content determination.

The moisture contained in a material comprises ALL the substances which vaporizes on heating leads to weight loss of the sample.

Other substances

• Organic solvents

• Alcohol

• Greases

• Oils

• Aromatic components (decomposition and combustion products)


2. Advantages of this method compared with other.

Much faster reading and determination of the moisture content.

Accuracy of the Percent moisture data gathered.

Easy and hassle free to operate.

Analyzes broad variety of materials


3. Importance to know moisture content of acacia and starch in tablet production:

Standard Properties of Acacia/ starch:

3a. Stability and agglomeration in powders

3b. Microbiological stability

3c. Flow properties


• To cont.

3d. Dry substance content and conc/ purity

3e. Commercial grade

3f. Nutritional value of the product

3g. Legal conformity


• Calculations

Formula to determine percent moisture:

% moisture = weight loss X 100

Start up weight

What if: Initial weight- 10 grams

After heating- 8.9625 grams

SOLUTION:


Start up weight

=_____-_____ X 100

=

=


5. Principle involved to determine moisture content using moisture analyzer

Moisture content data is provided as a percentage of initial mass of the residual dry mass.

Principle in Moisture analyzer

QUARTZ GLASS HEATER

SAMPLE

Constant even drying on the sample at selected temperature

The analysis automatically terminates when drying is complete, dry weight is stable at a fixed time

Other METHODS of Moisture content determination

1. Thermo-gravimetric method

-Are weighing- drying method in which samples are dried until their mass is constant.

-These are suitable for all thermally stable substances with a moisture content of >0.1%


• Examples of Thermogravimetic methods

1. Infrared drying

2. Halogen drying

3. Drying oven with balance

4. Microwave drying


2. Chemical analysis ex. KARL FISCHER method

-Used for many substances as reference method.

-A chemical analysis procedure which is based on oxidation of sulfate by iodine in a methanolic hydroxide soln.


• KARL FISCHER METHOD

- Drugs that contain no constituents volatile at 105C

- Samples with high moisture content

- Water contents in PPM

• CALCIUM CARBIDE


3. Spectroscopic method

-Indirect measurement method that requires calibration to determine the relation between the display of spectrometer and the value determined by a reference method.


• Examples of Spectroscopy methods

1. Infrared spectroscopy

2. Microwave spectroscopy

3. NMR


4. OTHERS

Density determination

Refractometry

Conductivity

Gas Chromatography

Azeotropic (Toluene Distillation)

Deo point and electrolyte hygrometer

DATA RESULT and sample calculation

ACACIA STARCH

Weight of the sample before

14. 987 grams 15.366 grams

Weigh of the sample after

14.958 grams 15. 297 grams

Percent moisture CALC

? ?

Percent moisture MA

0.1935% 0.4490

SOLUTION: ACACIA


Start up weight

=_____-_____ X 100

=

=

SOLUTION: STARCH


Start up weight

=_____-_____ X 100

=

=

Health & Medicine

Moisture analyzer 6/22 LECTURE NOTES