YSI pHotoFlex STD Colorimeter - Manual (Page 33)

pHotoFlex
®
STD Operation
33 ba76122e01 02/2013
4.5 Photometry
4.5.1 General information
Photometric measurements serve to determine chemical substances in
liquid samples. For this determination, the substance to be determined
has to be present in a form that is suitable for photometric measure-
ment. At the same time, possible disturbing factors have to be exclud-
ed.
Before measurement, the sample has to be pretreated in order to bring
the substance to be determined into the form that is suitable for mea-
surement and at the same time exclude disturbing factors.
Pretreatment of the sample is described in the analysis specification.
In a simple case, pretreatment can be to dissolve a solid substance in
water; it can, however, also include chemical conversions, e. g. a di-
gestion.
The chemicals required in the analysis specification are available as
test sets.
Suitable analysis specifications for test sets can be found in the pho-
tometry analysis manual (on CD-ROM).
There you will also find further instructions on handling chemicals and
on how to proceed when applying the analysis specifications.
Methods and the corresponding method data for many test sets are
stored as programs in the pHotoFlex
®
STD. A program number is as-
signed to each program.
The stored method data are loaded when the program number is en-
tered or read in with the aid of a bar code reader.
You can look up an overview of the available methods in the photome-
try analysis manual and display it on the screen of the pHotoFlex
®
STD
(see section 4.5.8).
You can measure the following parameters with the pHotoFlex
®
STD:
 Concentration[mg/l]
 % Transmission []
 Absorbance []