SKALAR METHODS
ANALYSIS: CHLORIDE
RANGE: 10 - 1000 mg Cl/kg
(≈ 2 – 200 mg Cl/liter)
SAMPLE: SOIL EXTRACT
SAN++
Catnr. 239-510 issue 042120/99358149
PRINCIPLE
The automated procedure for the determination of chloride is based on the following reaction; the
thiocyanate is liberated from the mercury(II) thiocyanate by the formation of unionized but soluble
mercuric chloride. With the present ferric ion, the free thiocyanate forms a red colored complex which is
measured at 470 nm.
LABORATORY FACILITIES
1. Maximum power consumption depending on the analyzer configuration, 2000 VA. Check voltage at the
back of the instrument before installation.
2. Facilities for chemical wastes. Check environmental regulations for proper disposal of waste.
PROCEDURE SAMPLE PREPARATION
Preparation methodology for chlorides: to 30 g of soil sample 150 ml of distilled water is added. Then water
extract is prepared.
Water no. 1.1.1
Field of application
Sample preservation for the determination of boron, bromide, chloride and fluoride in water.
Principle
The sample needs no special requirements before analysis.
Remarks
1. The sample should be analyzed within one month.
2. Store the samples for boron and fluoride in polyethylene bottles.
Note: The sample preparation in this method is only meant to be an example procedure. It requires
validation on its correct procedure for all types of samples to be analyzed, which is the responsibility of the
user.
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REAGENTS
A. Nitric acid solution (1 liter)
Required chemicals: Nitric acid .................. 15.8 ml. Preparation: Dilute the nitric acid in ± 800 ml distilled
HNO3 (65%) water. Fill up to 1 liter with distilled water,
Distilled water add the Brij 35 and mix.
H2O
Brij 35 (30%)................... 3 ml. Note: To improve linearity a small amount of
chloride can be added 0.2-1.0 ml of
10,000 mg Cl/liter stock solution.
Solution is stable for 1 week. Store at 4°C
when the solution is not used.
B. Distilled water + Brij 35 (1 liter)
Required chemicals: Distilled water Preparation: Dilute the Brij 35 in 1 liter distilled water
H2O and mix.
Brij 35 (30%)................... 3 ml.
Note: Solution is stable for 1 week. Store at 4°C
when the solution is not used.
C. Color reagent (1 liter)
Required chemicals: Mercury(II) Preparation: Dissolve the mercury(II) thiocyanate in
thiocyanate ............... 945 mg. the methanol. Dissolve the iron(III) nitrate
Hg(SCN)2 in ± 500 ml distilled water. Add the nitric
Methanol ................... 225 ml. acid. Add the methanol mixture to the
CH3OH distilled water + nitric acid and iron(III)
Iron(III) nitrate ............ 45.5 g. nitrate mixture. Fill up to 1 liter with
Fe(NO3)3.9H2O distilled water and mix thoroughly.
Nitric acid .................... 7.1 ml.
HNO3 (65%) Note: Prepare 24 hours before use. Solution is
Distilled water stable for 1 week. Store in dark colored
H2O bottle. Degas before use!
D. Rinsing liquid sampler
Required chemicals: Distilled water Note: Refresh weekly.
H2O
STANDARDS
Stock solution 10,000 mg Cl/liter (1 liter)
Required chemicals: Sodium chloride ...... 16.484 g. Preparation: Dissolve the sodium chloride in ± 800 ml
NaCl distilled water. Fill up to 1 liter with
Distilled water distilled water and mix.
H2O
Note: Solution is stable for 1 month.
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Working standards
200 mg Cl/liter: Dilute 2.0 ml stock solution 10,000 mg Cl/liter to 100 ml with rinsing liquid sampler.
160 mg Cl/liter: Dilute 1.6 ml stock solution 10,000 mg Cl/liter to 100 ml with rinsing liquid sampler.
120 mg Cl/liter: Dilute 1.2 ml stock solution 10,000 mg Cl/liter to 100 ml with rinsing liquid sampler.
80 mg Cl/liter: Dilute 0.8 ml stock solution 10,000 mg Cl/liter to 100 ml with rinsing liquid sampler.
40 mg Cl/liter: Dilute 0.4 ml stock solution 10,000 mg Cl/liter to 100 ml with rinsing liquid sampler.
Note:
1. Prepare the working standards fresh daily.
2. The water used for the reagents and standards must be degassed properly before making up the
reagents and standards. Especially water produced by reverse osmosis or ion exchange equipment
contains a lot of gasses, which must be removed by degassing (degassing procedure see operational
remarks and troubleshooting).
3. For better accuracy in low level analysis, more calibration standards must be added below 20%
standard.
CATALOGUE NUMBERS REQUIRED CHEMICALS
Product Supplier and catnr. Danger classification
Nitric acid (65%) Merck 100456 corrosive
Brij 35 (30%) Skalar 13900
Mercury(II) thiocyanate Merck 104484 very toxic, dangerous for the
environment
Methanol Merck 106008 highly flammable, toxic
Iron(III) nitrate nonahydrate Merck 103883 irritant
Sodium chloride Merck 106404
Hydrochloric acid (32%) Merck 100313 corrosive
Oxalic acid dehydrate Merck 100495 harmful
RECOMMENDED OPERATIONAL SETTINGS
1. System sample time: 40 sec., wash time: 40 sec., air time: 0 sec.
2. Module sample time: 40 sec., wash time: 40 sec., air time: 0 sec.
3. Calibration type: 1st order ISO 8466-1.
OPERATIONAL REMARKS AND TROUBLESHOOTING
1. The stabilizing time of the system is approximately 20 minutes.
2. The sensitivity of the highest standard 1000 mg Cl/kg ≈ 0.500 AU.
3. It is recommended to set the baseline to 0.200 - 0.500 AU (200.000 - 500.000 DU). The baseline can be
set using the Offset ADC for digital detector channel in the Peak Detection Type menu of the Method
Setup. Every step lowers the base line for 0.300 AU (300.000 DU).
4. Persons using this Skalar method should be familiar with normal laboratory practice. This Skalar
method does not purport to address all of the safety problems, if any, associated with its use. It is the
responsibility of the user to establish appropriate safety and health practices and to ensure compliance
with any national regulatory conditions.
5. The connection between the sampler and the sample pump tube is made of 5175 tube.
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6. If a digital matrix photometer 28505901, is in use, a correction interference filter of 620 nm ± 10 nm is
advised.
7. Avoid any turbidity in the reagents, filter if necessary.
8. After 6 months the amount of Brij 35 can be reduced to 1 ml/liter.
9. The reagent bottles must be rinsed thoroughly with distilled water before refilling with fresh reagents.
This is done to remove precipitation of microorganisms and other interferences.
10. If solvents or high concentrated acids (> 2M) must be controlled by a rinsing valve, use the solvent/acid
resistant type.
11. If the sample take up volume is less than 1.00 ml/min, a bypass is required to increase the sample
stream to at least 1.00 ml/min. For 5210 debubbler, when the sample is 1.00 ml/min and higher use
0.23 ml/min debubble tube.
12. Degassing procedures;
a) Good: degas the water with a helium gas flow of approximately 20 liter/hour with aid of a sparger.
Degas 5 liter water for 15 minutes. This procedure removes all dissolved air or, degas the water by
boiling the water for 10 minutes. Cool down to room temperature before usage.
b) Medium: degas the water with a nitrogen gas flow of approximately 20 liter/hour with aid of sparger.
Degas 5 liter water for 15 minutes. This procedure will remove most of the dissolved air.
c) Bad: degas the water by ultrasonic waves. This procedure will remove a small part of the dissolved air.
START UP PROCEDURE
1. Prepare all the reagents and standards.
2. Check if the pump deck(s) requires grease (catnr. 2010).
3. Close the pump deck(s).
4. Switch on the sampler, chemistry unit and interface.
5. Put the reagent lines in the appropriate reagent canisters.
6. Wait for approximately 30 minutes for a stable baseline and flow.
7. Start the analysis.
SHUT DOWN PROCEDURE
1. Put all reagent lines in distilled water.
2. Rinse with distilled water for 30 minutes.
3. Switch off the sampler, chemistry unit and interface.
4. Open pump deck(s).
MAINTENANCE
1. Daily: When daily analysis is finished rinse all reagent lines with distilled water for 15 min.
2. Weekly: To decontaminate the system, rinse with 1M hydrochloric acid solution for 15 minutes and with
distilled water for 30 minutes.
3. Monthly; 30 minutes with oxalic acid solution (40 g/liter) and 15 minutes distilled water. Replace pump
tubes (or shift the color bridges one position).
DIALYZER MAINTENANCE
Instructions to change catnr. 5283 and 5282 ready mount dialyzer membrane;
1. Unscrew the dialyzer block and remove the old membrane.
2. Clean the dialyzer block on both sides with a brush.
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3. Open the package and carefully remove the new membrane.
4. Rinse the new membrane with a small amount of distilled water to remove the excess preservation liquid.
5. Centre the membrane on the bottom dialyzer plate.
6. Make a cross incision with a blade in the membrane on the 2 center holes of the dialyzer bottom plate.
7. Make several small holes in the membrane through the holes for the mounting screw-bolts.
8. Position carefully the dialyzer top plate on the bottom plate.
9. Push the screw-bolts carefully through the membrane and tighten the screw-bolts, finger tight.
10.Tighten screw-bolts with an Allan-key (starting with the inside), carefully tighten down in stages to hand
tight.
11.Rinse the system several minutes with distilled water to remove the preservation liquid from the
membrane.
Important:
1. When the analyzer is not in operation the membrane should remain in contact with water. Never leave
the membrane dry.
MODULE CONSUMABLES
silicone tube catnr. 3150 sleeves catnr. 5401
polyethylene tube catnr. 3142 membrane catnr. 5283
polyethylene tube catnr. 5141 pump tube 1.40 ml/min. catnr. 3033
polyethylene tube catnr. 5142 pump tube 0.32 ml/min. catnr. 3027
polyethylene tube catnr. 5145 pump tube 1.20 ml/min. catnr. 3032
sleeves catnr. 5400 pump tube 1.00 ml/min. catnr. 3031
MODULE COMPONENTS
manifold holder catnr. 25200105 glass coil catnr. 5323
module catnr. 5108 connector catnr. 9220
end block catnr. 5109 dialyzer catnr. 5274
inlet connector catnr. 9245 clamps small catnr. 5111 3x
inlet connector catnr. 9241 sinkers catnr. 5380
inlet connector catnr. 5246 flow cell 10 mm catnr. 6401
glass coil catnr. 5325 filter 470 nm catnr. 6527
REFERENCES
Chemical method (no. 239)
1. ISO 15682:1999, Determination of chloride by flow analysis (CFA) and photometric or potentiometric
detection.
2. Zall, D.M., Fisher, D., Garner, M.Q.,”Photometric determination of chloride in water”, Anal. Chem 28,
1956, page 1665-1668.
3. Betteridge, D., Anal. Chem. 50, 1978, 832A.
4. Skeggs, L.T., Hochstrasser, H.,”Multiple automatic sequential analysis”, Clin Chem 1964, page 918-936.
5. ISO 3696:1987, Water for analytical laboratory use. Specification and test methods
6. ASTM, D1193, Standard Specification for Reagent Water.
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Sample preparation (water no. 1.1.1)
1. Environmental Protection Agency, methods for chemical analysis of water and wastes, 1983.
2. Standard methods for the determination of water and waste water, 17th edition, 1989.
3. ASTM, 1990
4. International Organization for Standardization, ISO-5667-3.
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