ISO 15682 pdf download – Water quality -Determination of chlorideby flow analysis (CFA and FIA) and photometric or potentiometric detection.
a) Dissolve 31 g of iron(lll) nitrate nonahydrate (3.3.5) in approximately 500 ml of water.
b) In a 1 000 ml volumetric flask dissolve 0.629 of mercury thiocyanate (3.3.2) in 150 ml of methanol (3.3.3) while constantly stirring. Add 100 ml of water (3.3.1). 3.4 ml of nitric acid 1(3.34). and the above•mentioned aqueous solution of iron nitrate. Make up to volume with water (3.3.1). Stir the solution for 2 h and filter.
The solution is stable for three months in a dark place.
C) Before analysis, degas the reagents for 10 mm, e.g. by membrane filtration (under pressure).
3.3.10 ChlorIde stock solution I, p = 10 000 mg/I.
Dissolve 16,509±0,05g of sodium chloride (3.3.6) in water (3.3.1) and make up to a volume of 1000 ml with water.
The solution is stable for one year.
3.3.11 Chloride stock solution Ii, ,‘ – 100 ing.’l.
AddS ml of stock solution 1(3.3.10) in a 500 ml volumetric flask and make up to volume with water.
The solution is stable for three months.
3.3.12 CarrIer solution for FIA (Cl In FIgures 8.1 and B.2).
Water (3.3.1) shall be used.
3.3.13 Carrier solutions for CFA (C2 and C3 in Figure B.4).
-— C2 Dilute 8 ml of nitric acid 1(3.3.4) w, approximately 900 ml of water in a 1000 ml volumetnc flask. Add I ml of detergent solution (3.3.8) and make up to volume with water.
C3: Dilute 4 ml of nitric acid 1(3.3.4) m approxriately 900 ml of water in a 1000 ml volumetric flask. Add 1 ml
of detergent solution (3.3.8) and make up to volume with water
3.3.14 CalibratIon solutions.
Prepare the calibration solutions by diluting stock solution I or 11(3.3.10 or 3.3.11).
Use a minimum of at least live calibration standards per working range. For example, if six standards are used. proceed for the working ranges Ito Ill as folIows
a) Range 111(1 mg/i to 10mg/I):
Pipette I ml. 3 ml, 5 ml. 6 ml. 8 ml, and 10 ml respectively of stock solution 11(3.3.11) Into a series of 100 ml
volumetric flasks. Make up to volume with water.
The mass concentrations of chloride in the resulting calibration solution are 1 mg/i, 3 mg/i, 5 mg/i, 6 mg/I.
8mg/i, and 10 mg/i respectively. These calibration solutions are stable for one week
b) Rangell(10 mgltolDOmg/i):
Pipette 10 ml. 30 ml, 50 ml. 60 ml. 80 ml. and 100 ml respectively of slock solution 11(3.3.11) into a series of 100 ml volumetric ttasks. Make up to volume with water.
3.4.3.1 Graduated flasks, nominal capacity 100 ml, 200 ml and 1 000 ml.
3.4.3.2 Graduated pipettes. nominal caclty 1 ml io 100 ml.
3.5 Sampling and sample pretreatment
Store the samples in either glass or plastic containers for up to one month Sample preservation is not required
(see ISO 5667’3).
3.6 Procedure
3.6.1 Preparation of the measurement
a) Assemble the flow analysis system (FIA or CFA) in accordance with the flow diagrams (3.4.1, 3.4.2; Figures B.1 to 8.4).
b) Before analysis, insert the tubes of the carrier solutions Cl to C3 (3.3.12. 3.3.13) and the reagent solution (3.3.9) Into the appropriate canisters. Run the system for 10 mm. Wait for a stable baseline and adpust the baseline to zero.
C) When the baseline shows no more drift, the system is ready for analysis. Check the reagent blank in accordance with 3.6.3 and calibrate in accordance with 3.6.4.
3.6.2 QualIty requirements for the measuring system
3.6.2.1 Instrument performance check
The absortance pet centimetre of optical pathlength measured for the calbation solulions (3.3.14) shall be in Ihe range from 0,03 102,0.
NOTE It the photorneinc deteclor does not give any abeotance readegs. the absorbance may then be determined by conipanson with an external abeorbance-measunng spectrometer.
3.6.2.2 Daily sensitivity adjustment
It a recorder for the calculation of results is used, transfer the sample probe into a chloride Calibration solution
(3.3.14) with the highest concentration of the selected working range (10 mgI, 100 mgI or 1 000 mgi, respectively).
When there is a positive response at the registration unit ie to the colour produced from the calration solution.
adjust the response to read about 95% of tull-scale deflection.
3.6.3 Checking the reagent blank
The reagent solution (3.3.9) shall not exceed an absorbance per centimetre of optical path length of 0,3. Otherwise consider the water as contaminated with chloride and take alternative steps. The absorbance can be measured by an external spectrometer.
ISO 15682 pdf download – Water quality -Determination of chlorideby flow analysis (CFA and FIA) and photometric or potentiometric detection
