Anions(Non-suppressor Method: Other Columns)

(RSpak KC-811 Column)

Organic acids were analyzed using RSpak KC-811.

Sample :
1. Citric acid
2. Malonic acid
3. Succinic acid
4. Lactic acid
5. Formic acid
6. Acetic acid

Column       : Shodex RSpak KC-811 (8.0mmID*300mm)
Eluent       : 3mM HClO4 aq.
Flow rate    : 1.0mL/min
Detector     : Non-suppressed coductivity, UV(210nm)
Column temp. : 60deg-C

Sulfurous acid in red wine was analyzed using RSpak KC-811.

Sample : Wine(red)
1. SO32-

Column       : Shodex RSpak KC-811 (8.0mmID*300mm)
Eluent       : 0.5mM HClO4 aq.
Flow rate    : 1.0mL/min
Detector     : ECD (Pt electrode)
Column temp. : 40deg-C

Silicic acid and boric acid were analyzed using RSpak KC-811.

Sample : 100micro-L
(A) Standards 20mg/L each
1. Silicic acid
2. Boric acid

(B) Tap water (Water)
1. Silicic acid

Column       : Shodex RSpak KC-811 (8.0mmID*300mm)
Eluent       : 0.5mM HClO4 aq.
Flow rate    : 1.0mL/min
Detector     : Shodex RI
Column temp. : 40deg-C

Sulfurous acid is a weak acid and can be separated by ion exclusion chromatography using RSpak KC-811. (A) is a chromatogram of standards. (B) is a chromatogram of directly injection of diluted wine and only free sulfurous acid is detected. (C) is a chromatogram of diluted wine to which NaOH is added before injection. By the addition of NaOH, all sulfurous acid in the wine is converted to free sulfurous acid and the amount of total sulfurous acid can be analyzed.

Sample : (B), (C); Wine
1. SO32-
2. Uric acid

Column       : Shodex RSpak KC-811 (8.0mmID*300mm)
Eluent       : 12mM H3PO4 aq.
Flow rate    : 1.2mL/min
Detector     : ECD (Electrode;Pt, 600mV SCE)
Column temp. : 40deg-C

Arsenic acid and arsenious acid also can be separated by ion exclusion chromatography using RSpak KC-811.

Sample : 100micro-L
1. Arsenate, AsO43- (20mg/L)
2. Arsenite, AsO2– (5mg/L)

Column       : Shodex RSpak KC-811 (8.0mmID*300mm)
Eluent       : 12mM H3PO4 aq.
Flow rate    : 1.0mL/min
Detector     : UV(195nm)
Column temp. : 40deg-C

(Other Columns)

Sulfide ion and Cyanide ion were analyzed using IEC DEAE-825 (a column for weak anion exchange chromatography) and an electrochemical detector (ECD).

Sample : 20micor-L
1. HS–, Sulfide ion
2. CN–, Cyanide ion

Column       : Shodex IEC DEAE-825 (8.0mmID*75mm)
Eluent       : 10mM Na2CO3 + 1mM Ethylenediamine + 10% CH3OH
Flow rate    : 1.0mL/min
Detector     : ECD (Electrode; Silver, 0mV SCE)
Column temp. : 25deg-C

Carbonate ion is contained in almost all aqueous samples and plays an important role for the ion balance. Therefore, simultaneous analysis of seven common anions (F–,Cl–, NO2–, Br–, NO3–,PO43-, SO42-) together with carbonate ion can be considered as an important target for deveolpment. Previously there have been examples of analysis including a suppressed IC method using NaOH eluent and a non-suppressed IC method using, a polymethacrylate column, but they were not satisfactory enough in peak shape, peak separation and detection sensitivity. The present method uses IC SI-90 4E and allows the baseline separation of seven common anions together with carbonate ion by non-suppressed IC using the eluent, p-hydroxybenzoic acid, pH 8.2.

(Pretreatment with the cartridges packing Na+ type cation exchange resin)
1. Rinse the cartridge with 3mL of methanol and 3mL of H2O separately.
2. Load 3mL of the sample onto the cartridge.
3. Waste 1mL of the first elution.
4. Collect 2mL of following elution.

Sample : 100micro-L each
Anion standards
1. F– 2mg/L
2. HCO3– 20mg/L
3. Cl– 3mg/L
4. NO2– 5mg/L
5. Br– 10mg/L
6. NO3– 10mg/L
7. PO43- 15mg/L
8. SO42- 15mg/L

River water (Water)
2. HCO3–
3. Cl–
4. NO2–
5. Br–
6. NO3–
7. PO43-
8. SO42-

Column       : Shodex IC SI-90 4E (4.0mmID*250mm)
Eluent       : 5mM p-Hydroxbenzoic acid + 5.3mM N,N-Diethylethanolamine aq.
Flow rate    : 1.0mL/min
Detector     : Non-suppressed conductivity
Column temp. : 25deg-C

Samples containing more than 10mg/L of Mg2+ and/or 20mg/L of Ca2+ must be pretreated, because those divalent cations form complexes with the eleuent and give rise to broad peaks which interfere with the analysis. For pretreatment,samples are passed through a pretreatment cartridge packed Na+ type cation exchange resin. This replaces the divalent cations in samples by Na+ and removes the interferring peaks.

(Pretreatment with the cartridges packing Na+ type cation exchange resin)
1. Rinse the cartridge with 3mL of methanol and 3mL of H2O separately.
2. Load 3mL of the sample onto the cartridge.
3. Waste 1mL of the first elution.
4. Collect 2mL of following elution.

Sample : Mineral water (Water), 100micro-L
1. HCO3–
2. Cl–
3. NO3–
4. SO42-

Column       : Shodex IC SI-90 4E (4.0mmID*250mm)
Eluent       : 5mM p-Hydroxbenzoic acid + 5.3mM N,N-Diethylethanolamine aq.
Flow rate    : 1.0mL/min
Detector     : Non-suppressed conductivity
Column temp. : 25deg-C