Hanna Instruments HI 4003 - Manual (Page 12)

12
Procedure
1) Follow sections VIII and IX to prepare sensors for
measurement.
2) Follow section VI to prepare standards / solution.
Standards should bracket and fall within the range of
interest.
Two mL HI 4000-00 ISA is added to 100 mL of both
samples and standards. Add stir bar and mix before
taking measurements.
3) Follow section VII; General Guidelines to optimize test
set-up.
4) During calibration it is best to start with lower concen-
tration samples first. Wait for a stable measurement
before recording values. Slightly longer equilibra-
tions are required at lower concentrations .
5) To prevent carry over and contamination of samples,
rinse sensors with deionized and dab dry with
absorbant laboratory tissue between samples.
XII. XII. XII. XII. XII. Other Measurement T Other Measurement T Other Measurement T Other Measurement T Other Measurement Techniques echniques echniques echniques echniques
Known Addition (for Cd 2+ )
An unknown concentration can be determined by adding a
known amount (volume and concentration) of measured
ion to a known volume of the sample. A mV value is taken
before and after the addition of standard, and using the
equation provided, the unknown concentration is found.
Typical Linearity of HI 4003 and HI 4103 Cadmium Sensors
-280
-260
-240
-220
-200
-180
-160
-140
-120
-100
1.0 2.0 3.0 4.0 5.0 6.0 7.0
-LOG [M]
mV