Procedures for colored or turbid samples
22
NANOCOLOR
®
UV
/
VIS
II and
NANOCOLOR
®
VIS
II V 1.1 / 10.2017
solution, the sample solution needs to be inserted. Pressing
starts the measurement
process. After the measurement has been completed, the measurement result will be
displayed in the result window. Via
and the icons below the result window, different
sample information can be added. Removal of the cuvette or leaving the menu via the task
bar icons quits the measurement process and stores the measurement
result in the
measurement memory of the device.
5.2.3
Bio tests
NANOCOLOR
®
bio tests can be retrieved in the device in different ways. The
cuvettes are equipped with a bar code. If the instrument is set to the home screen
or to a measurement menu, then the cuvette can be inserted and the barcode will
be read automatically. The corresponding cuvette test will be activated in the device and the
measurement will be started automatically (automatic measurements are not performed for
bio tests that have to be measured against a zero solution). The desired test can also be
retrieved by entering the test number (see section 5.7). After completion of the
measurement, the result will be displayed in the measurement window. Via
and the icons
below the result window, various types of sample information can be added (see section
5.2.1). Removing the cuvette or exiting the measuring menu via the other icons in the taskbar
quits the measurement, and the result will be stored in the measured value memory of the
instrument.
5.3
Procedures for colored or turbid samples
These instructions are to be applied only in conjunction with the original instructions of the
NANOCOLOR
®
cuvette tests.
The photometric analysis of water samples with inherent color
or turbidity always requires determination of a correction value. Color and turbidity both
cause increased light absorption (increased absorbance), which leads to wrong results.
Determination of correction values requires
individual procedures for every test.
For example, it is not possible simply to measure the color of the sample without reagents
and then substract this value from the test result. In many cases, the reagents alter the color
or turbidity of the sample. All changes of the sample during analysis, such as dilution or
addition of chemicals which alter pH or redox state have to be taken into account. Only the
main reagent, which forms the measured color complex, is not added.
For the spectrophotometers
NANOCOLOR
®
UV
/
VIS
II and
VIS
II, after the normal analysis
(value A) is completed, activate the correction value program (see Figure 20) by selecting the
“Correction value” entry via the
icon in the result window.
The instrument asks for the cuvette with the correction value (value B) and measures the
correction. The corrected measurement result is displayed and stored. For some tests it is
neccessary to measure an additional blank value.
Basic procedure:
Determine measuring result as per original instruction = A
Determine correction value as per special instruction = B
Analytical result = A
– B
Exceptions: Methods, where decreasing absorbancess are measured against a reagent
blank value. In these cases, analytical result = A + B. The corresponding analytical
instructions point out this fact.
It is very important to substract only values with equal dimensions (e.g. mg/L N; mg/L NH
4
;
mmol/m
3
; E).
If, in the same matrix, the correction factor for several samples is so low that it can be
neglected, it may be possible to work without correction. However, this conclusion can only
be drawn from practical experience and cannot be predicted!
For measurement of the correction value use a clean, empty test tube filled with distilled
water as a blank value (exceptions: test 0-59 / 0-64 / 0-65 / 0-66).
Summary of Contents for NANOCOLOR UV/VIS II
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