Coulometric Method
1.General Samples
AQUAMICRON™ AXI/CXU
AQUAMICRON™ AX/CXU
AQUAMICRON™ AS/CXU
Points
- Normally AXI/CXU or AX/CXU should be used.
- AS is used for specimens that do not dissolve readily in AXI or AX.
Alternatively, the AXI or AX to which chloroform is added can be used for such a specimen (approximately 20 vol%)
When to change the reagent
- When 100ml of AXI (AX, AS) increases to around 150ml with the addition of the specimen.
- When CXU has turned dark brown, or when decreasing of background is poor.
- When the cumulative amount of moisture measured per 100ml of AXI, AX or AS exceeds 800mg.
- When the cumulative amount of moisture measured per 5ml of CXU exceeds 150mg.
- When the measurement time is prolonged.
Coulometric Method
2.Amines
AQUAMICRON™ AXI+salicylic acid/CXU
AQUAMICRON™ AX+salicylic acid/CXU
Points
- With amines that show strong-basicity (pKa8-9 or higher), add salicylic acid to adjust the pH of the anolyte.
- 10g of salicylic acid is placed in the electrolyte cell and dissolved in 100ml of AXI or AX.
- Approximately 70mmol with 10g of salicylic acid
→ The equivalent of 70mmol of amines can be measured continuously.
Coulometric Method
3.Ketones, Lower Carboxylic Acid
AQUAMICRON™ AKX/CXU
Points
- When problems are encountered, such as poor background decrease or slow measurement, it is possible that the detection electrodes may be contaminated. Wipe them lightly with a tissue paper, etc.
- Solid ketones are unlikely to cause interference reactions (ketal reaction) and can therefore be measured using general-purpose AXI or AX.
When to change the reagent
- If the measurement time increases when more specimen is added, or if decrease of background deteriorates.
- When CXU has turned dark brown.
- When the cumulative amount of moisture measured per 100ml of AKX exceeds 300mg.
- When the cumulative amount of moisture measured per 5ml of CXU exceeds 300mg.
Coulometric Method
4.Solids, Powders (Moisture vaporization method)
AQUAMICRON™ AXI/CXU
AQUAMICRON™ AX/CXU
Points
- Normally, 150-180ml of AXI or AX and 10ml of CXU are used with the moisture vaporization method.
- AKX is used if the substances vaporized from the specimen include ketones.
- Extended used of moisture vaporization equipment will cause a reduction of AXI or AX due to methanol evaporation. Add commercially available methanol.
When to change the reagent
- If the measurement time increases or it decrease of background deteriorates.
- See 1.General Samples for information about the quantities of specimens for which moisture can be measured.
Volumetric Method
5.General Specimens
SS-Z/GEX
SS/MS
Points
- Normally 50ml of dehydrated solvent GEX (MS) is used (with Nittoseiko Analytech equipment).
- It is necessary to determine the titer of the SS-Z (SS).
E. g. Use Aquamicron™ Water Standard 10mg.
When to change the reagent
- When 50ml of dehydrated solvent increases to 150ml with the addition of SS-Z (SS) and the specimen (general specimens).
Volumetric Method
6.Amines
SS-Z/GEX
+salicylic acid
SS/MS
+salicylic acid
Points
- With amines that show strong-basicity (pKa8-9 or higher), add salicylic acid to adjust the pH of the titration solvent.
- Place 10g of salicylic acid in a titration flask and dissolve it in 50ml of dehydrated solvent.
- Approximately 70mmol with 10g of salicylic acid.
→ The equivalent of 70mmol of amines can be measured continuously.
Volumetric Method
7.Petroleum Products and Oils
SS-Z/OLX
SS/CM
Points
- Some specimens may not dissolve completely. These substances can be measured, however, since moisture will be extracted into the methanol while dispersed.
- OL II, containing chloroform, is still suitable for measuring the moisture of fats.
Precautions when Disposing of Waste Liquid
- SS, CM and OL II are containing chloroform.
Volumetric Method
8.Sugers and Condiments
SS-Z/SU
SS/FM
Points
- If the specimen is difficult to dissolve, SU (FM) can be heated to 40°C. This will require a mantle heater and special titration flask (sold separately).
- With substances that contain large amounts of oils, such as chocolate, it is useful to add about 5ml of chloroform to the SU (FM).
- The recovery rate for SU (FM) will be low initially.
- The titer of SS-Z (SS) can be determined with a general-purpose product.
- Measure the sample after first measuring 5-10\\l of water to determine the recovery rate.
Volumetric Method
9.Ketones
SS-Z/KTX
SS/CP
Points
- Pyridine-free and chloroform-free dehydrated solvents for use with ketones are not compatible with pyridine-type products. Always use the same type pf products (SS-Z and KTX, or SS and CP)-General-use, oil or sugar dehydrated solvents can also be used.)
- Solid ketones are unlikely to cause interference reactions and can therefore be measured with general-purpose dehydrated solvents.
Precautions when Disposing of Waste Liquid
- SS/CP contains chloroform.
Volumetric Method
10.Aldehydes
SS/PP
Points
- Aldehydes tend to cause interference reactions.
- The amount of specimen used should be kept to a minimum in order to reduce the interference reactions.
- Only SS (pyridine types) are available.
Volumetric Method
11.Solid, Powders (Moisture Vaporization Method)
SS-Z/GEX+PG
SS/MS+PG
Points
- With the moisture vaporization method, use approximately 100-120ml of solvent.
- Add commercially available propylene glycol (PG) to GEX (MS) in the ratio of 1:3 to prevent blockages in the blowing pipe and reduce evaporation.
E. g. Add approximately 25ml of PG to approximately 75ml of GEX (MS) to make a total of 100ml.
When to change the reagent
- When the amount of dehydrated solvents exceeds 150ml due to the addition of SS-Z (SS) and the specimen.
12.Other Substances
- There may be situations in which another method is preferable to the KF method, or when the flowchart does not apply.
- For specific inquiries, please contact us.
Product Manager for Aquamicron
Nittoseiko Analytech Co., Ltd.
2-3-4, Nihonbashi, Chuo-ku, Tokyo, 103-0027 Japan
TEL :+81-46-278-0052
FAX :+81-46-278-0053
E-mail: mcckf@cc.m-kagaku.co.jp