ALTANA LCM III - Manual (Page 30)

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Standard Operations
5.4 Sampling and sample preparation
Take a representative sample from the product you want to
measure in accordance with DIN EN ISO 15528 (or ASTM
D3925-02).
If the material shows any visual haziness, remove the haze by
either filtration, centrifugation, heating, ultrasonic treatment or
suitable means.
Heat partly solid samples before measuring in order to dissolve the
solid material in the liquid. The preparation must not cause any
chemical changes in the sample.
Make sure that during the measurement are no bubbles in the
sample.
There are three cuvette/sample cell types available for color
measurement with the LCM III, differing by material (glass, PS and
PMMA) and path length (10 mm,11 mm and 50 mm). Fill the
cuvette/sample cell to approximately 2 cm. The light beam passes
through the cuvette/sample cell around 0.5 cm to 1.5 cm above the
base of the cuvette/sample cell.
The program calculates and displays Iodine, Hazen, Gardner,
Saybolt, Klett and ASTM D 1500 color values automatically, taking
into account the cuvette/sample cell type.
A dry thermostat is available for the 11 mm disposable round glass
cuvettes/sample cells. The dry thermostat heats the
cuvettes/sample cells to any temperature between ambiant and
150 °C.
Important Note: The samples must be clear and free of turbidities.
If products in paste or solid form cannot be measured directly, the
product must be melted before being transferred to the
cuvettes/sample cells. Make sure the cuvettes/sample cells do not
contain any air bubbles.
• Always hold the cuvette/sample cell close to the top, to make
sure that there are no fingerprints in the measurement zone of
the cuvette/sample cell. Use suitable transfer pipettes to
introduce samples into the cuvettes/sample cells.
• Slowly add samples to the cuvettes/sample cells cells to make
sure air bubbles do not form on the cuvette/sample cell wall
and in the sample. Air bubbles will cause false readings.
• If air bubbles are entrapped, remove them by heat, vacuum,
ultrasonic treatment or other suitable means.
• Clean the outside of the cuvettes/sample cells thoroughly
before inserting them in the cell compartment.
Important Note: Before using disposable cuvettes/sample cells
made by PS (Polystyrene) or PMMA (Polymethyl methacrylate) be
sure that the cuvettes/sample cells will not be destroyed by
samples, otherwise the cell compartment can be damaged.