5.2 Resolving Common Troubleshooting Issues
5
5.2.2 Solvent Flow Does Not Stabilize
If solvent delivery pressure is unstable, it indicates a problem with the solvent delivery pump.
Does liquid flow out of the drain tube during purging?
Is the suction tube filled with liquid?
NO Æ
Manually purge the flow channels, degas the mobile phase, clean the suction filter, and purge the flow channels.
ÈYES
Is there any leakage around the pump head?
NO
Æ Rinse/replace the check valve.
ÈYES
Replace the plunger seal.
Check the plunger status. If any damage or
contamination is discovered, replace the plunger and diaphragm at the same time.
5.2.3 Solvent Delivery Pressure Increases
If the solvent delivery pressure starts increasing, blockage may have occurred in one of the high-pressure flow channels.
Use the following procedure to disconnect flow channels and check the pressure, starting from the downstream end.
Solvent delivery pressure increases.
ÈYES
Does the pressure increase occur after disconnecting flow channels between the detector and column?
NOÆ Inspect the detector flow channels.
ÈYES
Does the pressure increase even after disconnecting the tubing between the column and autosampler outlet tubing?
NO
Æ Inspect/replace the column.
ÈYES
Does the pressure increase even after disconnecting the tubing between the
autosampler outlet tubing and high pressure valve?
NO Æ
Does the pressure increase even after backflushing the outlet tubing?
YESÈ
Replace the outlet tubing.
ÈYES
Does the pressure increase even with the needle raised (in the loading position)?
NO
Æ Inspect/replace the needle seal, needle, and sample loop.
ÈYES
Does the pressure increase even after disconnecting the inlet tubing from the high pressure valve and
autosampler inlet tubing?
NOÆ
Has the high pressure valve rotor been used more times since it was new or after replacement than indicated in the replacement guideline?
NOÆ
Rinse the high pressure valve flow
channels.
ÈYES ÈYES
Inspect the mixer, solvent delivery pump, and mobile phase bottles.
Replace the high pressure valve rotor and then inspect/replace the stator.
5.2 Resolving Common Troubleshooting Issues
5
Do NOT pump solvent through the solvent delivery pump if any high pressure flow channel parts are removed.
Be sure to shut OFF the solvent delivery pump flow before disconnecting tubing or a sample loop, needle, needle seal, or any other part from a high pressure flow channel.
Confirm that the mobile phase delivery pressure, indicated in the solvent delivery pump screen, has dropped to zero before disconnecting a part from a high pressure flow channel.
Wear protective goggles and protective gloves whenever disconnecting high pressure flow channel parts.
Getting solvent in the eyes could cause loss of sight. If a solvent gets in the eyes, immediately rinse them with running water and seek treatment from a physician.
The following are possible causes for flow channel blockage.
Cause of Clogged
Tubing Corrective Action
Insoluble Substances in Mobile Phases
Insoluble substances in mobile phases can cause blockage in tubing or columns. Visually check inside bottles for preexisting undissolved insoluble substances and for suspended or precipitated components in mobile phases.
Insoluble matter in samples
Insoluble matter in samples or mobile phases can cause blockage in tubing and columns. If cloudiness or insoluble substances are observed in sample solutions, use a commercially marketed disposable filter to filter the sample solution in advance.
Required
Supplies Disposable filter
Airborne
microparticles/debris in the environment
It is also possible the blockage was caused by dust or debris from the environment that entered via the injection port. That is typically not a problem, because the instrument front panel is normally closed during analysis, but avoid performing maintenance or otherwise working with the front panel open in locations with high levels of debris, dust, or other matter.
Debris from the Needle Seal Installed in the Injection Port
A needle seal is installed in the injection port. If the needle becomes slightly out of alignment for some reason, it could potentially generate needle seal debris. If that generates needle seal wear debris, it could potentially cause tubing blockage. If needle misalignment at the injection port is observed, the injection port position must be adjusted.
SIL-40 CL Series Instruction Manual
Cause of Clogged
Tubing Corrective Action
Wear debris from septa used on sample vials
Blockage could potentially be caused by debris from septa used on sample vials. Various types of septa made of different materials and with different surface coatings are available. Septa specified by Shimadzu have passed repetitive injection tests and solvent
resistance tests before being released as products. Normally, a thin film of solvent resistant material (such as PTFE) is adhered to the septum surface to prevent generating septum debris from the needle piercing the septum. However, using septa not specified by
Shimadzu can result in generating septum debris from the needle piercing the septum, which could cause blockage.
To avoid such problems, only use septa and sample vials specified by Shimadzu.
Wear Particles from the High Pressure Valve Rotor/Stator
Repeated rotations of the high pressure valve can generate wear particles from the rotor or stator. Due to the extremely small size of such wear particles, they rarely cause tubing blockage, but can sometimes cause blockage at the column inlet. Periodically replace rotors and stators according to specified rotor/stator replacement guidelines.
Tubing blockage can be avoided by using tubing with a larger internal diameter. However, doing so does not address the core problem and is, therefore, not really considered a desirable solution.
In such cases, the debris that would cause the tubing blockage can cause blockage at the column inlet. Therefore, first try the
countermeasures indicated above. These same precautions also apply when this unit is used in combination with a non-Shimadzu LC system.
SIL-40 CL Series Instruction Manual Required
Supplies Methanol or 2-propanol
Microparticles
emitted from solvent delivery pump
The following substances potentially could be emitted from the solvent delivery pump.
• Contamination of suction filters, line filters, etc.
Whenever new parts are installed, be sure to rinse the parts with methanol or 2-propanol (15 minutes at 5 mL/min) before
connecting them to this unit.
• Plunger seal wear particles
Such substances become trapped in the pump line filter, so periodically replace the line filter.
Required
Supplies Methanol or 2-propanol
Contamination of the tubing itself
If the tubing is replaced with new tubing, rinse the tubing thoroughly before connecting it to the instrument. If tubing is rinsed, rinse it with methanol or 2-propanol (15 minutes at 5 mL/min).
Required
Supplies Methanol or 2-propanol
5.2 Resolving Common Troubleshooting Issues
5
5.2.4 Baseline Does Not Stabilize
If the baseline does not stabilize, it indicates a problem with the detector, flow channel, or other related part.
Troubleshoot the cause using the following procedure.
Is there
leakage from a flow channel?
YES
Æ Tighten the leaking connection.
ÈNO
Does the baseline stabilize after the solvent flow is stopped?
NO
Æ Does the baseline fluctuate at the same frequency as the room temperature?
YES Æ
Prevent air flow from directly hitting the instrument.
If a detector with
temperature-co ntrol
functionality is used, check whether or not the setting is enabled.
ÈNO
Check the detector performance.
・ Inspect/rinse the cell. (Is the cell contaminated?)
・ Check the lamp illumination time.
(Has the cumulative time exceeded the replacement guideline?)
ÈYES
Does solvent flow stabilize if a flow restrictor is connected instead of the column?
NO Æ
The following are possible causes.
・ Instability due to room temperature fluctuations of the mobile phase or tubing.
Be careful of the air conditioner air flow direction and temperature fluctuations.
・ Flow channel contamination.
Rinse flow channels with a solvent compatible with the mobile phase.
Also rinse contaminated areas using a solvent that dissolves the contaminant substance.
・ Change in the dissolved oxygen content in the mobile phase.
Keep the mobile phase temperature constant and degas it thoroughly.
・ Change in mobile phase composition.
Seal reservoir bottles and leave them in a location with minimal temperature variations.
Equilibrate the column
thoroughly.
If the column is
contaminated, rinse it according to the instruction manual.
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Corrective Measures for Leakage from the Cell Window
If leakage occurs from the flow cell window, wipe off the leakage with a paper wipe, for example, and then tighten the cell window fastening screws by turning them clockwise with a regular screwdriver. (The slot in cell window fastening screws is 1 mm wide and 8 mm long. The regular screwdriver part number is 086-10412-01.) If
tightening the cell window fastening screws does not resolve the leak, contact a Shimadzu representative.
5.2.5 Noise Appears in Baseline
If noise appears in the baseline, it indicates a problem with the detector, flow channel, or other related part.
Troubleshoot the cause using the following procedure.
Is there leakage from a flow channel?
YES
Æ Tighten the leaking connection.
ÈNO
Does it stabilize when a back pressure is applied to the cell?
NO Æ
There might be bubbles in the cell.
Remove bubbles from inside the flow cell.
ÈYES Check the detector performance.
・ Inspect/rinse the cell. (Is the cell contaminated?)
・ Check the lamp illumination time. (Has the cumulative time exceeded the replacement guideline?)
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Corrective Measures for Bubbles
How to Remove Bubbles from Inside the Flow Cell
While pumping solvent, apply pressure inside the cell by pressing a fingertip, a rubber
5.2 Resolving Common Troubleshooting Issues
5
Preventing Bubble Formation
• Thoroughly degas mobile phases before use. (Use a degassing unit.) For mobile phases that cannot be degassed or that are especially prone to forming bubbles, connect a 0.
3 mm I.D. × 2 m long tube to the cell outlet.
• Connecting the 0.3 mm I.D. × 2 m tubing applies about 0.2 MPa of back pressure when water is pumped at 1 mL/min. For safety reasons, disconnect the flow cell from the instrument before applying back pressure to check for leakage. If leakage occurs, tighten the cell window fastening screws with a regular screwdriver.
• Contamination on walls inside the flow cell makes it easier for air bubbles to collect in the cell (especially when using water-based mobile phases). Rinse the flow cell with a liquid such as alcohol.
SPD-40 CL Instruction Manual
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Corrective Measures for Leakage from the Cell Window
If leakage occurs from the flow cell window, wipe off the leakage with a paper wipe, for example, and then tighten the cell window fastening screws by turning them clockwise with a regular screwdriver. (The slot in cell window fastening screws is 1 mm wide and 8 mm long. The regular screwdriver part number is S086-10504-18.) If
tightening the cell window fastening screws does not resolve the leak, contact a Shimadzu representative.
5.2.6 Poor Area Value Reproducibility
If area reproducibility is unstable, it indicates a problem with the solvent delivery pump, autosampler, column, detector, or other related part.
Troubleshoot the cause using the following procedure.
Is the pressure fluctuating or has it dropped or are retention times unstable?
YES Æ
If the solvent delivery pump flow is unstable, then area values and reproducibility are also unstable.
Check the solvent delivery pump for pulsation, leakage, etc.
ÈNO
Is the baseline fluctuating? YES Æ
If the baseline is fluctuating, then area values and reproducibility will fluctuate. Stabilize the baseline.
ÈNO
Was the measuring flow channel in the autosampler not purged before analysis?
NO Æ
Inadequate degassing of solvents in the measuring flow channel could cause insufficient suction. Purge the measuring flow channel thoroughly.
ÈYES
Was the needle stroke not changed after changing the vial type used?
NO Æ
If the needle stroke is too low or too high, it could prevent accurate suctioning. Specify the needle stroke based on the containers used.
ÈYES
Are vials filled with sample up to the vial opening?
YES Æ
Negative pressure during suctioning could cause insufficient suctioning.
Limit filling to about 70 % of vial capacity.
ÈNO
Are peak integration settings not specified appropriately?
NOÆ Adjust baseline correction, peak detection points, etc.
ÈYES
Does reproducibility vary depending on the component or do values decrease when left in vials for a while?
YES Æ
For some vial materials, samples could adsorb to vial walls. Change the vial material.
5.2 Resolving Common Troubleshooting Issues
5
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Manual purge of Autosampler
If air bubbles remain in the measuring pump of Autosampler, area value repeatability and injection volume accuracy will deteriorate. If performance does not improve even after repeated purges, perform manual purge according to the following procedure.
1 Push in and pull up the soft switch (A) to remove it from the tray (B) and put it beside the instrument so that it does not get in the way.
Do NOT pull hard on the soft switch.
The flat cable (C) is connected to the soft switch. Pulling hard on the switch after removing it from the tray may break the flat cable.
The soft switch (A) is fixed to the catch (b) of the tray (B) by the hook (a) at the bottom. Pushing in the switch releases the hook from the tray and enables you to pull up the switch.
• The figure is the side view of the instrument seen from the left.
2 Loosen the mail nut (A) on the front side of the measuring pump with a spanner (8 mm width) and remove the piping.
3 Screw adapter (A) into syringe (B) and connect to the front of the measuring pump with a mail nut.
Part number Part name Remarks
228-15672-91 ADAPTOR,SYRINGE Mail nut is included.
046-00017-01 SYRINGE,H4020-LL_16913
* All are included in the tool kit (228-57647-43).
4 Start the purge operation of the Autosampler and aspirate the rinse solution with the syringe.
It is recommended to aspirate at least 9 mL. Since the syringe volume is 3 mL, it is necessary to repeat the operation of removing the syringe from the adapter, emptying the contents, reattaching it, re-aspirating three times.
5 Stop the purge operation and attach the piping and soft switch as it was.
After the manual purge is complete, purge the Autosampler as usual.
5.2 Resolving Common Troubleshooting Issues
5
5.2.7 Carryover Does Not Disappear
If carryover cannot be eliminated, it indicates a problem with the flow channels that samples flow through, such as the autosampler or column.
Troubleshoot the cause using the following procedure.
Were the needle exterior, needle interior, and other areas not rinsed?
YES Æ
Autosamplers include rinsing
functionality. Rinse the exterior and interior surfaces of the needle with solvent.
ÈNO
Does carryover occur for only certain specific samples?
YES Æ
Change the type of rinse solution and rinse method based on the chemical properties of the compounds being carried over. (Example: A
water/methanol/acetonitrile/2-propanol (1/1/1/1) solution containing 0.1 % formic acid.)
Compounds that tend to form chains with metals can adsorb to columns and stainless steel tubing. Confirm whether changing to a metal-free column or PEEK tubing reduces carryover.
ÈNO
Did carryover occur when the same sample was analyzed in the past?
YES Æ
Replace the consumables, such as the needle and needle seal. Alternatively, check whether the needle is shifted out of position.
ÈNO
Does carryover disappear after several blank injections?
YES Æ
Disconnect the outlet tubing and other flow channel joints through which samples pass, carefully wipe off the tubing end surfaces, and reconnect the tubing.
ÈNO
For gradient analysis, does carryover disappear if only the gradient is executed with the autosampler inlet and outlet tubing connected via a coupling?
YES Æ
Sample material is remaining inside the column or outlet tubing. Replace them with new parts.
In the cases of LC and other high-sensitivity analysis, carryover can also occur from sources to which samples are exposed, other than flow channels, such as mobile phase bottle contamination.
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Hardware
Symptoms Main Cause Location to
Check Corrective Action
No power is supplied when power switch is switched ON.
Is power cord unplugged?
Main power
switch Plug in the power cord properly.
Is there a broken/open circuit in the power cord?
Main power switch
Replace it with a power cord of the same type.
Are the power supply
specifications appropriate for the specified instrument power requirements?
Main power switch
Use a power supply that meets the power supply specifications for the instrument.
No solvent is delivered at all.
(The solvent delivery pump does not function.)
Was [PUMP]
clicked? Is [PUMP]
illuminated?
Solvent delivery pump
Click [PUMP]. [PUMP] is illuminated.
Does the flowrate display remain at “0”?
Solvent delivery
pump Specify the flowrate.
Is an error displayed (such as
“P-MAX” or
“P-MIN”)?
Solvent delivery pump
Click [CE] and eliminate the cause of the error.
5.3 Troubleshooting
5
Symptoms Main Cause Location to
Check Corrective Action
The solvent delivery pump runs, but does not pump solvent.
Is the mobile phase bottle empty?
Mobile phase Add mobile phase.
Is the drain valve open?
Solvent delivery
pump Close the drain valve. *1 Is liquid leaking
from a flow channel connection?
Solvent delivery pump
Tighten the connection. If the leak persists after tightening the connection, then replace the connection.
Are there bubbles inside the pump head?
Solvent delivery pump
Click [PURGE] to purge the bubbles. Alternatively, connect a syringe to the drain tube
connection port to suction out the bubbles.
"2.3.3 Manual Purging the Solvent Delivery Pump"
P.26 Is there air
entering via a connection between the suction filter and pump?
Solvent delivery pump
Connect the suction filter fitting securely.
Is the check valve defective?
Solvent delivery pump
Pump 2-propanol to rinse the check valve. However, if a buffer solution is being used, rinse the check valve with purified water first. Then rinse it by pumping 2-propanol.
If rinsing the valve is not effective, clean the check valve ultrasonically or replace it.
Symptoms Main Cause Location to
Check Corrective Action
Solvent delivery is unstable and pump pulsation is large.
Flowrate is lower than the setting value.
Is the check valve defective?
Solvent delivery pump
Pump 2-propanol to rinse the check valve. However, if a buffer solution is being used, rinse the check valve with purified water first. Then rinse it by pumping 2-propanol. If rinsing the valve is not effective, clean the check valve ultrasonically or replace it.
Is the check valve contaminated?
Solvent delivery pump
Pump 2-propanol to rinse the check valve. However, if a buffer solution is being used, rinse the check valve with purified water first. Then rinse it by pumping 2-propanol. If rinsing the valve is not effective, clean the check valve ultrasonically or replace it.
Is the suction filter clogged?
Solvent delivery pump
Ultrasonically clean the suction filter. If ultrasonic cleaning is not effective, then replace it.
Are there bubbles in the suction filter tubing?
Solvent delivery pump
Click [PURGE] to completely purge the old mobile phase.
Vibrate the suction filter to purge the bubbles. If the suction filter is clogged*2, clean it ultrasonically. If ultrasonic cleaning is not effective, then replace it. Degas the mobile phase.
Are there bubbles inside the pump head?
Solvent delivery pump
Click [PURGE] to purge the bubbles. Alternatively, attach a syringe to the drain tube connection port and suction out the bubbles.
"2.3.3 Manual Purging the Solvent Delivery Pump"
P.26 Is there previous
mobile phase remaining inside the pump head?
Solvent delivery pump
Click [PURGE] to completely purge the old mobile phase.
Is liquid leaking from the gap between the pump head and head holder?
Solvent delivery pump
Replace the plunger seal. If leakage continues after replacing the plunger seal, then replace the plunger.
LC-40 CL Series Instruction Manual
Is there leakage from the plunger seal?
Solvent delivery pump
Replace the plunger seal. If the plunger seal service life was extremely short, then also replace the plunger.
5.3 Troubleshooting