Справочник Пользователя для Hanna Instruments c 214
12
The instructions listed below should be carefully followed during testing
to ensure most accurate results.
to ensure most accurate results.
COLLECTING AND MEASURING SAMPLES
• For adding the exact amount of sample or liquid reagent to the
reagent vials it is strongly recommended to use the available
Hanna automatic fixed-volume pipettes or class A laboratory pipettes
(symbolized like a generic pipette tip in the following parameter
related chapters):
Hanna automatic fixed-volume pipettes or class A laboratory pipettes
(symbolized like a generic pipette tip in the following parameter
related chapters):
pipette code
volume
HI 731340
200 µL
HI 731341
1000 µL
HI 731342
2000 µL
For correct use of the automatic pipette, please follow the related
Instruction Sheet.
Alternatively, it is possible to use the optional
Instruction Sheet.
Alternatively, it is possible to use the optional
HI 740142 1 mL
graduated syringe or
C115-00300 5 mL graduated syringe. For
the correct use of the syringes, see instructions below.
1. In order to measure exactly e.g. 5 mL of reagent with the 5 mL
syringe:
(a) push the plunger completely into the syringe and insert the
(a) push the plunger completely into the syringe and insert the
tip into the solution.
(b) pull the plunger up until the lower edge of the seal is exactly
on the 5 mL mark.
(c) take out the syringe and clean the outside of the syringe tip.
Be sure that no drops are hanging on the tip of the syringe, if
so eliminate them. Then, keeping the syringe in vertical
position above the vial, push the plunger completely down
into the syringe. Now the exact amount of 5 mL has been
added to the vial.
so eliminate them. Then, keeping the syringe in vertical
position above the vial, push the plunger completely down
into the syringe. Now the exact amount of 5 mL has been
added to the vial.
TIPS FOR AN ACCURATE MEASUREMENT
(
c
)
(
a
)
(
b
)
69
• Place the sample vial into the holder
and push it completely down.
• Press READ DIRECT and "SIP" will blink on the display.
• The instrument directly displays concentration in
mg/L of phosphate
(PO
4
3-
) on the Liquid Crystal Display.
• To convert the reading to mg/L of P
2
O
5
, multiply by a factor of
0.748.
• To convert the reading to mg/L of phosphorus (P) concentration,
multiply by a factor of 0.326.
Note: for accurate measurements
1) wash glassware only with phosphate-free detergents
2) clean all glassware with 1 : 1 hydrochloric acid solution and rinse with
deionized water.
1) wash glassware only with phosphate-free detergents
2) clean all glassware with 1 : 1 hydrochloric acid solution and rinse with
deionized water.
INTERFERENCES
Interference may be caused by:
Bismuth:
Bismuth:
negative error
Fluoride:
negative error
pH:
the sample should have a neutral pH
Sulfide:
negative error .
To eliminate sulfide: add Bromine Water drop-wise
until a pale yellow color develops; remove Bromine
Water excess by adding Phenol solution drop-wise.
To eliminate sulfide: add Bromine Water drop-wise
until a pale yellow color develops; remove Bromine
Water excess by adding Phenol solution drop-wise.
Temperature: the method is temperature sensitive.
It is recommended to run measurements at T = 20 to 25 °C:
T < 20 °C causes a negative error
T > 25 °C causes a positive error
T < 20 °C causes a negative error
T > 25 °C causes a positive error
Turbidity:
turbidity and suspended matter in large amounts may
cause interference because the strongly acidic reaction
conditions may dissolve suspended matter or cause
desorption of phosphates from particles. Before
measurement, turbidity or suspended matter should
be removed by treatment with active carbon and by
prior filtration.
cause interference because the strongly acidic reaction
conditions may dissolve suspended matter or cause
desorption of phosphates from particles. Before
measurement, turbidity or suspended matter should
be removed by treatment with active carbon and by
prior filtration.
Phosphorus, Reactive HR