Hach-Lange LICO 690 Basic User Manual - Manual (Page 53)

English 53
Take and prepare samples
Take a representative sample from the product you wish to measure in
accordance with DIN EN ISO 15528 (or ASTM D3925-02).
If the material shows any signs of turbidity, remove this turbidity by
filtration, centrifuging, heating, ultrasound treatment or other 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 there are no bubbles in the
sample.
For the color difference measurement, three cuvette types are available
that differ in terms of material (glass, PS and PMMA) and path length
(10 mm, 11 mm and 50 mm). Add approx. 2 cm of the sample to the
cuvette. The light beam passes through the cuvette approx. 0,5 cm to
1,5 cm above the bottom of the cuvette.
The program calculates the iodine, Hazen, Gardner, Saybolt, Klett and
ASTM D 1500 color values automatically and displays the color values.
The cuvette type being used is taken into consideration.
Photometry
(only
LICO 690)
Single Wavelength
Single wavelength readings are:
Absorbance readings: The light absorbed
by the sample is measured in absorbance
units.
Transmittance reading (%): Measures the
percent of the original light that passes
through the sample and reaches the
detector.
Concentration readings: A concentration
factor can be entered to enable the
measured absorbance values to be
converted into concentration values.
Multi Wavelength
In the Multi Wavelength mode, absorbance
(Abs) or percentage transmittance (%T) is
measured at up to four wavelengths and
absorbance differences and absorbance
relationships are calculated. Simple
conversions into concentrations can also be
carried out.
Time course
The time scan records the absorbance or %
transmittance at a wavelength over a defined
time.
Wavelength Scan
A wavelength scan shows how the light from
a sample is absorbed over a defined
wavelength spectrum. This function can be
used to determine the wavelength at which
the maximum absorbance value can be
measured. The absorbance behavior is
displayed graphically during the scan.
System Checks
The "System Check" menu contains a
number of options, such as instrument
information, optical checks, instrument
backup, service times, instrument update,
settings for analytical quality assurance and
lamp history.
Recall measurement data
Saved data can be retrieved, filtered, sent to
a printer, memory stick or PC and deleted.
Table 3 Main Menu options
Option Function
Instrument Setup
This menu is used to configure user-specific
and/or process-specific settings: operator ID,
date and time, security settings, saved data,
sound, PC and printer and energy
management.
Table 3 Main Menu options
Option Function