IC Column Selection and Troubleshooting

IC Column Selection
The world leader in serving science
1
Thermo Scientific Dionex IonPac Columns
• Anion-Exchange Columns
• Hydroxide Selective
• Carbonate Selective
• Cation-Exchange Columns
• Ion-Exclusion Columns
• Concentrator and Trap Columns
2
When to Use Hydroxide-Selective Columns
• Trace analyte determinations
• Gradient resolution of complex samples
• Large loop injection analyses
• Easier integration of early-eluting compounds
• Combine with Eluent Generation for best overall
performance
• Routine anion analysis (Dionex IonPac™ AS18 and
Dionex IonPac AS18-4µm)
3
When to Choose High Capacity
Choose High Capacity
• When analyzing organic
acids and inorganic anions
in high ionic strength
matrices
• For best resolution of
weakly retained anions
(such as monovalent
organic acids)
• For complex matrices
where increased column
ruggedness is desirable
4
Choose Lower Capacity
• For analysis of simple
samples, where analytes
are present at similar
concentrations
• For fast profiling of
inorganic anions and
organic acids in wellcharacterized samples
Hydroxide-Selective Dionex IonPac
Anion-Exchange Columns
5
Column
Formats
Primary Application
Dionex IonPac
AS11-HC-4µm
0.4 × 250
mm
High resolution, high capacity column for the
determination of organic acids and inorganic anions in
uncharacterized samples.
Dionex IonPac
AS18-4µm
0.4 × 150
mm
Recommended hydroxide selective column for fast high
resolution separations of inorganic anions in diverse
matrices.
Dionex IonPac
AS26
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
High capacity column for the separation of haloacetic
acids (HAAs) in drinking water. The capillary format is
used in the 2nd dimension of the 2D-IC method for HAAs.
Dionex IonPac
AS25
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
High capacity columns for the separation of multivalent
anions and polarizable anions (iodide and perchlorate)
including sulfur species (sulfite, sulfate, thiosulfate and
thiocyanate) in complex anions.
Dionex IonPac
AS24A
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
High capacity column for the separations of haloacetic
anions as well as a variety of environmental anions. The
standard bore column is used in the 1st dimension of the
2D-IC method for HAAs.
Hydroxide-Selective Dionex IonPac
Anion-Exchange Columns
Column
Formats
Primary Application
2 × 250 mm
Recommended hydroxide selective column for
haloacetic acids prior to MS or MS/MS detection. 2D method for trace bromate.
Dionex IonPac AS21
2 × 250 mm
Recommended hydroxide selective column for trace
perchlorate prior to MS or MS/MS detection. EPA
Method 331.0
Dionex IonPac AS20
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
Recommended hydroxide selective column for trace
perchlorate prior to suppressed conductivity
detection. EPA Method 314.1. Hydrophobic and
polyvalent anions.
Dionex IonPac AS19
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
Recommended hydroxide selective column for
inorganic anions and oxyhalides. Trace bromate in
drinking water.
Dionex IonPac AS18
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
High capacity hydroxide-selective column for the
analysis of common inorganic anions.
Dionex IonPac AS24
6
Hydroxide-Selective Dionex IonPac
Anion-Exchange Columns
Column
Formats
Dionex IonPac
AS18-Fast
0.4 × 150
mm
2 × 150 mm
4 × 150 mm
Hydroxide-selective column for fast analysis of
common inorganic anions.
Dionex IonPac
AS17-C
2 × 250 mm
4 × 250 mm
Low capacity for fast analysis of common inorganic
anions using gradient elution.
Dionex IonPac
AS16
2 × 250 mm
4 × 250 mm
High capacity for hydrophobic anions including iodide,
thiocyanate, thiosulfate, and perchlorate. Polyvalent
anions including: polyphosphates and
polycarboxylates. Trace perchlorate. EPA Method
314.1 & 332.0
Dionex IonPac
AS15
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
High capacity for trace analysis of inorganic anions
and low molecular weight organic acids in high purity
water matrices.
3 × 150 mm
Fast run, high capacity for trace analysis of inorganic
anions and low molecular weight organic acids in high
purity water matrices.
Dionex IonPac
AS15-5µm
7
Primary Application
Hydroxide-Selective Dionex IonPac
Anion-Exchange Columns
8
Column
Formats
Primary Application
Dionex IonPac
AS11-HC
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
High capacity for the determination of organic acids
and inorganic anions in uncharacterized samples.
Dionex IonPac
AS11
2 × 250 mm
4 × 250 mm
Low capacity for fast profiling of organic acids and
inorganic anions in well-characterized samples.
Dionex IonPac
AS10
2 × 250 mm
4 × 250 mm
High capacity for the analysis of inorganic anions and
organic acids in high nitrate samples.
Dionex IonPac
Cryptand A1
3 × 150 mm
Polarizable anions, polyvalent anions including
polyphosphates and polysulfonates.
Dionex IonPac Fast
Anion IIIA
3 × 250 mm
Recommended hydroxide selective column for
phosphoric and citric acids in cola soft drinks.
Carbonate-Based Dionex IonPac
Anion-Exchange Columns
9
Column
Formats
Primary Application
Dionex IonPac
AS23
2 × 250 mm
4 × 250 mm
Recommended carbonate-based column for inorganic
anions and oxyhalides. Trace bromate in drinking
water.
Dionex IonPac
AS22
2 × 250 mm
4 × 250 mm
Recommended carbonate-based column for fast
analysis of common inorganic anions.
Dionex IonPac
AS14A- 5µm
3 × 150 mm
Moderate column for fast analysis of common inorganic
anions.
Dionex IonPac
AS14A
4 × 250 mm
Moderate capacity for analysis of common inorganic
anions.
Dionex IonPac
AS14
2 × 250 mm
4 × 250 mm
Moderate capacity for fast analysis of common
inorganic anions.
Carbonate-Based Dionex IonPac
Anion-Exchange Columns
10
Column
Formats
Primary Application
Dionex IonPac
AS12A
2 × 200 mm
4 × 200 mm
Moderate capacity for analysis of inorganic anions and
oxyhalides. Trace chloride and sulfate in high
carbonate matrices.
Dionex IonPac
AS9-HC
2 × 250 mm
4 × 250 mm
High capacity column for inorganic anions and
oxyhalides. Trace bromate in drinking water.
Dionex IonPac
AS9-SC
4 × 250 mm
Low capacity for fast analysis of inorganic anions and
oxyhalides. Specified column in EPA Method 300.0 (B).
Dionex IonPac
AS4A-SC
2 × 250 mm
4 × 250 mm
Low capacity for fast analysis of common inorganic
anions. Specified column in EPA Method 300.0 (A).
Dionex IonPac Cation-Exchange Columns
Column
Formats
Dionex IonPac
CS19-4µm
0.4 × 250 mm
Dionex IonPac
CS19
11
0.4 × 250 mm
2 × 250 mm
4 × 250 mm
Primary Application
High resolution separation of inorganic cations and
small polar amines in complex matrices.
Separation of inorganic cations and small polar amines
in complex matrices.
Recommended column for polar amines
(alkanolamines and methylamines) and moderately
hydrophobic amines (biogenic amines, diamines and
polyamines). Nonsuppressed mode when extended
calibration linearity for ammonium and weak bases is
required.
Dionex IonPac
CS18
2 × 250 mm
Dionex IonPac
CS17
0.4 × 250 mm
2 × 250 mm
4 × 250 mm
Recommended column for highly hydrophobic and
polyvalent amines (biogenic amines and diamines).
Dionex IonPac
CS16
0.4 × 250 mm
3 × 250 mm
5 × 250 mm
Recommended column for disparate concentration
ratios of sodium and ammonium. Alkylamines and
alkanolamines.
Dionex IonPac Cation-Exchange Columns
Column
Primary Application
Dionex IonPac
CS15
2 × 250 mm
4 × 250 mm
Disparate concentration ratios of ammonium and
sodium. Trace ethanolamine in high-ammonium or highpotassium concentrations. Alkanolamines.
Dionex IonPac
CS14
2 × 250 mm
4 × 250 mm
Aliphatic amines, aromatic amines, and polyamines plus
mono- and divalent cations.
Dionex IonPac
CS12A-MS
2 × 100 mm
IC-MS screening column for fast elution and low flow
rates required for interfacing with IC-MS detectors.
Dionex IonPac
CS12A-5µm
12
Formats
0.4 × 150 mm Recommended column for high efficiency and fast
3 × 150 mm
analysis (9 minutes) of mono- and divalent cations.
Dionex IonPac
CS12A
0.4 × 250
mm
2 × 250 mm
4 × 250 mm
Recommended column for the separation of mono- and
divalent cations. Manganese morpholine, alkylamines,
aromatic amines, and quaternary ammonium ions.
Dionex IonPac
CS5A
2 × 250 mm
4 × 250 mm
Recommended column for transition and lanthanide
metals analysis. Aluminum analysis.
Dionex IonPac
SCS 1
2 × 250 mm
4 × 250 mm
Operated with nonsuppressed conductivity detection.
Can be used when extended calibration linearity for
ammonium and amines is required
Dionex IonPac Ion-Exclusion Columns
Column
Formats
Dionex IonPac
ICE-AS1
9 × 250 mm
4 × 250 mm
Dionex IonPac
ICE-AS6
Dionex IonPac
ICE-Borate
13
Primary Application
Ion-exclusion column for fast analysis of aliphatic
organic acids and alcohols in complex samples.
9 × 250 mm
Ion-exclusion column for aliphatic organic acids,
including hydroxy-substituted organic acids, and
alcohols in complex samples.
9 × 250 mm
Ion-exclusion column ideal for monitoring trace levels
of borate in high-purity water.
Determination of Common Anions in a Treated
Wastewater Sample
Column:
2
60
Dionex IonPac AS19
(0.4  250 mm)
Eluent Source: Thermo Scientific Dionex
EGC KOH (Capillary)
Gradient:
Potassium hydroxide
10–25 mM from 0 to 10 min,
25–70 mM from 10 to 20 min
13 mM from 17 to 20 min,
10 mM from 20 to 25 min
Flow Rate:
10 µL/min
Inj. Volume:
0.4 µL
Column Temp.:30 °C
Detection:
Suppressed conductivity,
Thermo Scientific Dionex
ACES 300, recycle mode
Sample Prep.: Filtered, 0.2 µm
5
4
µS
Peaks:
1
3
6
-1.0
0
14
Minutes
25
1. Fluoride
2. Chloride
3. Bromide
4. Nitrate
5. Sulfate
6. Phosphate
1.76 mg/L
180
0.42
11.8
96.9
0.94
Sulfur Species Analysis of a Simulated Acid-Gas
Scrubber Solution
Column:
70
Dionex IonPac AG25/ AS25
4  250 mm
Eluent:
Potassium Hydroxide:
20 mM from 0 to 5 min,
20–45 mM from 5 to 15 min,
45 mM from 15 to 30 min
Eluent Source: Dionex EGC III KOH
Flow Rate:
2.0 mL/min
Inj. Volume:
25 µL
Temperature: 30 °C
Detection:
Suppressed conductivity,
Thermo Scientific Dionex
ASRS 300, 4 mm,
AutoSuppression™,
recycle mode, 223 mA
Sample:
3% base diluted 10-fold
1
3
µS
2
0
-10
0
5
10
Minutes
15
20
Peaks:
1. Chloride
2. Carbonate
3. Sulfate
28428
15
Aliphatic Acids in an Acidic Matrix
Column:
Eluent:
Flow Rate:
Detection:
1.0
Sample:
µS
Peaks:
2
1
3 4
5
6
0.0
0
5
10
Minutes
16
15
20
Dionex IonPac ICE-AS6
10 mM Heptafluorobutyric acid
1.0 mL/min
Suppressed conductivity with
Thermo Scientific Dionex
AMMS-ICE Suppressor
0.25% Sulfuric acid, 50 µL
1. Citric
2. Malic
3. Glycolic
4. Lactic
5. Acetic
6. Succinic
0.5 mg/L
1.0
1.0
1.0
1.0
1.0
Determination of Trace Level Ammonium in a 10,000x
and 20,000x Higher Sodium Sample
Columns:
0.08
A
1
Eluent:
2
µS
Flow Rate:
0
0
0.40
2
4
6
B
8
10
1
µS
Temperature:
Inj. Volume:
Detection:
Peaks A:
2
Peaks B:
0
0
5
10
Minutes
17
15
20
Dionex IonPac CS16
A: 5  250 mm
B: 3  250 mm
A: 30 mM Methanesulfonic acid
B: 7 mM Methanesulfonic acid
for 23 min to 52 mM at 28 min
A: 1.0 mL/min
B: 0.43 mL/min
40 C
25 µL
Suppressed conductivity,
Thermo Scientific Dionex CSRS,
AutoSuppression, recycle mode
1. Sodium
2. Ammonium
1. Sodium
2. Ammonium
CTC-1 Column placed between
the Cell Out and Regen In Ports
100
mg/L
0.01
500
0.25
Determination of Trace Level Sodium in a 10,000x
Higher Ammonium Industrial Waste Sample
Columns:
Dionex IonPac CG16, CS16-5µm
(5  250 mm)
Eluent:
30 mM Methanesulfonic acid
Temperature: 40 C
Flow Rate:
1.0 mL/min
Inj. Volume:
25 µL
Detection:
Suppressed conductivity,
Dionex CSRS™, 4 mm,
AutoSuppression, recycle mode
Sample Prep.: 1:10 dilution
0.34
2
1
Peaks:
0.24
0
5
10
15
Minutes
18
20
25
1. Sodium
2. Ammonium
0.01 mg/L (ppm)
100
IC Column Troubleshooting
The world leader in serving science
19
Proper Maintenance of Your IC System is Required
• Take the time to perform periodic maintenance and
Save Time Later!
• Daily, Weekly, Periodic, and Monthly Maintenance is required for all
IC systems
• Read the manuals and perform the required maintenance for each
component in your system
• Eliminate the system first when troubleshooting
performance issues
20
Column Start Up Recommendations
• The columns are shipped in a storage solution, typically
sodium borate for anion columns and MSA for cation
columns
• Connect the new guard column and pump the Quality
Assurance Report (QAR) eluent directly to waste for
30 minutes
• Connect the new separator column to the guard column
and pump the QAR eluent directly to waste for
30 minutes
• Connect the new column set to the hydrated suppressor
• Inject the QAR solution multiple times, until consecutive
injections give reproducible retention times
• Proceed with your application
21
Reproduce the Quality Assurance Report (QAR)
• Reproduce the QAR by running the same analytes under
the same conditions
• Upon initial installation of a column
• Upon changing any components in the system
• Upon a noticeable change in performance
• The QAR includes the analysis of specific ions under
specific conditions that tell us about the performance of
the column
• The results of the QAR analysis can help troubleshoot
the system
22
Column Performance Issues
• Column Performance Issues
•
•
•
•
•
•
•
Fronting
Tailing
Low peak efficiency
Abnormal column pressure
Abnormal peak resolution
Abnormal retention time
Unknown peak (ion contamination)
• Column Troubleshooting Table from Manuals
23
Fronting
• Symptom
• Peak starts slow ascent compared with peak end slope
µS
• All peaks show same phenomenon, if the cause is the column
time
• Fronting is rarely improved by a column rinse or a reversed wash
• Possible causes
• Poor column packing
• Eluent mismatch for column
• Column overload by weakly retained analytes
• Column was mishandled, dropped, allowed to dry out
• Column damaged due to pulsed pressure fluctuation causing high back pressure
• Solution
• Dilute sample or inject less
• Replace the column
24
Tailing
• Symptom
• The slope of peak end is gentle compared with the peak start slope
µS
• All peaks show same phenomenon, if the cause is the column
• If tailing more pronounced on early eluters, could be due to poor connections
• Possible causes
• Poor connections, especially in capillary systems
• High sample concentration or high sample volume (overload)
• Contamination/sample adsorbed onto column resin (e.g. SO42-, PO43-, non-ionic
surfactant, metal)
• Head space or space between resin beads in column
• High column back pressure
• Drying of resin bed
• Solution
• Remake fittings one at a time until source is identified
• Dilute sample or inject less
• Clean column
• Replace column
25
time
Low Peak Efficiency
• Symptom
• Broad peak or split peak
• Possible Cause
• Excessive void volume (Sample diffusion in microbore system or capillary
system)
• Wrong eluent or wrong sample solvent
• Sample adsorbed onto column resin
• Contamination of bed support by sample or eluent
• Poor column packing
• Solution
•
•
•
•
•
26
Eliminate voids, leaks in the system
Use correct eluent
Dilute sample in water
Clean column, replace inlet bed support
Replace column
Abnormal Column Pressure (High)
• Symptom
• Increased operating pressure over time
• System shut down due to high pressure
• Long or short retention times
• Possible Cause
• Pump operating improperly
• Higher pressure produces shorter retention times
• Lower pressure produces longer retention times
•
•
•
•
•
•
27
Clogging in system
Crimped tubing
Contamination of column
Low column temperature
Mismatched eluent or organic solvent
Injection of sample that is insoluble in mobile phase
Abnormal Column Pressure (High) continued
• Solution
•
•
•
•
•
•
28
Remove blockage in system
Check all connections for uneven flow, remake connections
Filter samples
Clean column, replace bed support
Use correct eluent
Verify that oven temperature control is operating correctly
Abnormal Column Pressure (Low)
• Symptom
• Low pressure
• Possible Cause
• Pump lost prime
• Liquid leak
• High column temperature
• Solution
•
•
•
•
29
Prime the pump
Eliminate leak
Check pump seals
Use correct temperature
Abnormal Resolution
• Symptom
• Peaks not resolved
• Possible Cause
•
•
•
•
•
Column contamination
Headspace in column
High sample concentration or high sample volume
Disparate concentrations
Incorrect eluent
• Solution
•
•
•
•
•
30
Use correct eluent
Clean column/replace bed support
Dilute sample or inject less
Choose correct column
Replace column
Abnormal Retention Time (Shorter)
• Symptom
• Shortened retention time during operation
• Different retention time compared with previous batch of column
• Possible Cause
•
•
•
•
•
•
•
•
31
Incorrect eluent
Improper storage method
Column contamination
Column overload
Incomplete mixing of eluent in eluent container
Pump not operating properly
Wrong temperature being used
Small lot to lot variances in column manufacturing
Abnormal Retention Time (Shorter) continued
• Solution
•
•
•
•
•
Use correct eluent and storage solution
Clean column, replace bed supports
Dilute sample or inject less
Make sure eluent is properly mixed
Ensure pump is operating properly
• Operate column under recommended conditions
32
Abnormal Retention Time (Longer)
• Symptom
• Increased retention time during operation
• Different retention time compared with previous batch of column
• Possible Cause
• Incorrect eluent
• Pump not operating properly
• Small lot to lot variances in column manufacturing
• Solution
• Use correct eluent and storage solution
• Ensure pump is operating properly
33
Abnormal Retention Time (Varying)
• Symptom
• Varying retention time during operation
• Possible Cause
•
•
•
•
Not column related
Pump not operating properly
Injection valve not operating properly
Lack of temperature control
• Solution
• Ensure pump is operating properly, prime the pump
• Repair or replace injection valve
• Ensure column temperature is stable
34
Spurious Peaks
• Symptom
• Unexpected peaks in chromatogram
• Possible Cause
• If unusually wider than others, the spurious peak is from the previous injection
• If narrower than others, the spurious peak is from electronic source
• Excessive suppressor current
• Solution
• Increase time between injections
• Use recommended suppressor current
• Repair or replace injection valve
35
Troubleshooting in Column Manual
Observation
Cause
Action
High Backpressure
Unknown
Isolate Blocked Component
Plugged Column Bed
Support
Replace Bed Supports, Filter
Eluents and Samples
Other System
Components
Unplug or Replace
Large System Void
Volumes
Replumb the System
Column Headspace
Replace the Column
Flow Rate Too Fast
Calibrate the Pump
Incorrect Eluent
Concentration
Remake the Eluent
Column Contamination
Clean the Colum
Poor Resolution
Shortening Retention
Time
Please see the column or system manual for details
36
Troubleshooting in Column Manual
Observation
Cause
Action
Poor Front End
Incorrect Eluent Concentration
Remake Eluent
Resolution
Column Overloading
Reduce Sample Size
Sluggish Injection Valve
Service Valve
Large System Void Volumes
Replumb the System
Sample Contaminated
Pretreat Samples
Sluggish Injection Valve
Service Valve
No Injection
Check Configuration File
Spurious Peaks
No Peaks
Please see the column or system manual for details
37
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PP70258_E 9/12S