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<div class="container"><h1 class="title">Analog Connection to a Strip-Chart Recorder</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/RecorderConnect.jpg" alt="Analog Connection to a Strip-Chart Recorder" ></div> The detector can be connected to a recorder via the analog signal cable. <ol> <li>Attach the supplied signal cable to the RECORDER connection and recorder terminals as shown.</li> <li>Reconnect the power cables to the system units and turn ON the power switches of all the system units.</li> <li>Set the recorder RANGE.</li> </ol> <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon"><strong>CAUTION: If the signal cable is reversed at the recorder terminals, the chromatogram may be represented in a negative direction.</strong> <span class="btn-link">[[SPD Connections->Detector Connections]]</span><br> <span class="btn-link">[[Analog Connection to an Integrator->Analog Connection to an Integrator]]</span> <br> <span class="btn-link">[[Digital Connection to a System Controller->Digital Connection to a System Controller]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Analog Connection to an Integrator</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/ChromatopacConnect.jpg" alt="Analog Connection to an Integrator"></div> The detector can be connected to an integrator to monitor 1 or 2 channels. The optional Channel 2 accessory board is required to monitor the second channel. <ol> <li>Attach the detector signal cable to the INTEGRATOR connector and to the Chromatopac as shown.</li> <li>Reconnect the power cables to the system units and turn ON the power switches of all the system units.</li> </ol> <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon"><strong>CAUTION: If the signal cables are reversed, the chromatogram may be represented in a negative direction. </strong> NOTE: If dual wavelength mode is used, the AUX RANGE and REC MODE parameters must be set properly. <span class="btn-link">[[SPD Connections->Detector Connections]]</span><br> <span class="btn-link">[[Analog Connection to a Strip-Chart Recorder->Analog Connection to a Strip-Chart Recorder]]</span> <br> <span class="btn-link">[[Digital Connection to a System Controller->Digital Connection to a System Controller]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Back Pressure Tubing</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/LC-BackPress.jpg" alt="Back Pressure Tubing"></div> Shimadzu detectors are all supplied with a 2-meter length of tubing to be used as a back-pressure device. One function of this tubing is to apply back pressure to the flow cell outlet to prevent the generation of air bubbles in the flow cell. <ol> <li>Attach a male PEEK nut to one of the ends of the supplied 2m cell outlet tubing.</li> <li>Screw the male PEEK nut attached to the tubing into the outlet coupling (union).</li> <li>Insert the other end of the tubing into the waste container so that the outlet end is pointing down but above the surface of the liquid in the container.</li> </ol> <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon"><strong>CAUTION: Do not shorten the cell outlet tubing from the original 2m length.</strong> <br> <span class="btn-link">[[Mobile Phase Degassing->Mobile Phase Degassing]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Baseline Disturbance</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/BaselineDisturbance.jpg" alt="Baseline Disturbance"></div> <ul> <li>Upward drifting baselines usually result from an inadequately equilibrated column.Allow the column to equilibrate until the baseline stabilizes.</li><li>Downward drifting baselines are often caused by not allowing the lamp to heat sufficiently. Allow the lamp to heat for 30 minutes before examining the baseline.</li><li>A meandering baseline may be related to the cyclical temperature fluctuation of the column heating device. Use of a column oven can reduce the magnitude of this temperature cycling.</li><li>A wandering baseline is often related to ambient temperature fluctuations or contaminants eluting from a column. Thermally isolate the column and other system components that can be affected by temperature changes, and wash the column thoroughly.</li> </ul> <div class="ts-question">Does the baseline disturbance look more like group A and B than it does group C?</div> <div class="buttons"> <span class="btn-yes">[[Yes->Column Insulation]]</span> <span class="btn-no">[[No->ZERO Key]]</span> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Baseline is Not a Problem</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/BaselineStability.jpg" alt="Baseline is Not a Problem"></div> <div class="ts-question">The baseline does not pose a problem for the current application.<br>Please select a more appropriate Troubleshooting pathway.</div> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Bubbles in the Flow Cell</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/Sawtooth.jpg" alt="Bubbles in the Flow Cell"></div> <h3>Determine if gas is coming out of solution to form bubbles in the flow cell.</h3> Generally, the more dissolved air that is removed from the mobile phase the better the entire HPLC system will perform. However, when mobile phase does contain dissolved gas, the gas can escape from solution to form a small bubble in the flow line. These small bubbles can attach to any dirt particles that may be in the flow cell. As more gas escapes from solution, the bubble becomes larger causing a disturbance to the baseline. When the bubble gets large enough to flow out with the mobile phase, the baseline returns to zero. This phenomenon usually causes a very regular sinusoidal (sawtooth) shape to the baseline. It is also possible that the bubbles will manifest themselves as spiking vertical lines in the baseline. <div class="ts-question">When the flow is restarted, does the baseline disturbance have a sinusoidal (sawtooth) shape?</div> <div class="buttons"> <span class="btn-yes">[[Yes->Back Pressure Tubing]]</span> <span class="btn-no">[[No->Half Flow Rate]]</span> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Column Insulation</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/ColumnTemp.jpg" alt="Column Insulation"></div> <h3>''A column oven can be used to isolate the column and flow lines from the ambient temperature fluctuations.''</h3> Maintaining the column temperature at a constant level increases analysis reproducibility and separation performance. There are three different types of thermal insulation devices available for the LC column. <ul> <li>CTO-30A and the CTO-30AS with the SIL-30AC MP Column Oven - Uses a heating block to control the temperature of the LC column.</li> <li>CTO-20A/20AC Column Oven - Uses an air-circulated thermostatic chamber to maintain the temperature of the LC column and flow lines.</li> <li>Jacket-type Devices - Uses plumbing insulation or heat tape to a lesser degree of effectiveness.</li> </ul> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Detector Connections</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/SPD-Front.jpg" alt="Detector Connections"></div> Connections between the detector and data system vary depending on the type of data system being used. Some data systems connect digitally to the detector through the fiber optic cable, while others connect via analog signal cables. If the detector and data system are properly connected and the signal is either absent or unsuitable, check the data system parameters to ensure that the proper channels are being monitored. <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon"><strong>WARNING: Turn OFF all of the system units and unplug the power cables before performing any wiring procedures.</strong> Do not use cables or perform any wiring connections other than those specified in the detector User Manual. Failure to follow these warnings could result in fire, electric shock or instrument malfunction. <span class="btn-link">[[Analog Connection to an Integrator->Analog Connection to an Integrator]]</span><br> <span class="btn-link">[[Analog Connection to a Strip-Chart Recorder->Analog Connection to a Strip-Chart Recorder]]</span> <br> <span class="btn-link">[[Digital Connection to a System Controller->Digital Connection to a System Controller]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div>
<div class="container"><h1 class="title">Deuterium Lamp - SPD-M30A</h1> <div class="center"><iframe width="900" height="506" src="https://www.youtube.com/embed/leuCJwCon-k?rel=0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe></div> <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon"><strong>WARNING: Turn OFF the power to the instrument and unplug the power cable before proceeding.</strong> <ol> <li>Open the doors.</li> <li>Remove the lamp cover.</li> <li>Disconnect the deuterium lamp connector.</li> <li>Use a screwdriver to loosen the lamp retaining screws</li> <li>Remove the old lamp from the instrument.</li> <li>Install the new D2 lamp assembly.</li> <li>Secure the lamp retaining screws.</li> <li>Reconnect the lamp connector.</li> <li>Re-install the lamp cover.</li> <li>Close the doors.</li> </ol> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Digital Connection to a System Controller</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/FiberOpticConnect.jpg" alt="Digital Connection to a System Controller"></div> The fiber optic cable supplied with the unit provides two-way communication for both transmission and reception of the signals, and is connected to the REMOTE connector. <ol> <li>Before connecting the fiber optic cable, remove the cap from the REMOTE connection channel to be used.</li> <li>Insert the fiber optic cable plug into the REMOTE connector until it clicks into place. <ul> <li>Do not bend the fiber optic cable to less than a 35 mm radius.</li><li>Grasp the plug, not the cable, when inserting or removing the fiber optic cable.</li><li>Do not bend the cable where it joins the plug.</li> </ul></li> <li>Connect the other end of the cable to the system controller REMOTE connector.</li> <li>Insert the power plug into the outlet, and turn the power switch on.</li> </ol> <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon"><strong>CAUTION: Make sure the connector is not connected across two different channels.</strong> NOTE: Keep the removed cap in a safe place to use if the fiber optic cable is unplugged. Channels 3-8 of the system controller REMOTE connector are typically used for this purpose. If the fiber optic cable is not properly connected, 'Detector not linked' will be displayed. <span class="btn-link">[[SPD Connections->Detector Connections]]</span><br> <span class="btn-link">[[Analog Connection to an Integrator->Analog Connection to an Integrator]]</span> <br> <span class="btn-link">[[Analog Connection to a Strip-Chart Recorder->Analog Connection to a Strip-Chart Recorder]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Dirty Flow Cell</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/ReferenceSampleEnergy.jpg" alt="Dirty Flow Cell"></div> Compare the sample energy and reference energy to determine if the flow cell is dirty and absorbing energy. Click the appropriate lamp/detector link to learn how to check the reference and sample intensities for that detector. <span class="btn-link">[[Lamp Intensity - LCsolution->Lamp Intensity - LCsolution]]</span> <div class="ts-question">Is the difference in sample and reference energies greater than the acceptable limit?</div> <div class="buttons"> <span class="btn-yes">[[Yes->Flow Cell Cleaning - SPD-M30A]]</span> <span class="btn-no"><a href="https://www.ssi.shimadzu.com/forms/tech-support/index.html?product_category=VirtualAdvisor&product_name=Nexera&page=webform_start">No</a></span> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Half Flow Rate</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/Flow-Half.jpg" alt="Half Flow Rate"></div><h3>Now determine whether the baseline disturbance is pump related. Set the flow rate to 1/2 of the previous rate.</h3> Because it is not always possible to determine whether the baseline disturbance occurs with the pump stroke, it may be necessary to change the flow rate to see if this affects the baseline disturbance. By lowering the flow rate and watching the baseline disturbance, it is possible to determine whether or not the problem is related to the pump <ul> <li>If the frequency of the baseline disturbance slows when the flow rate is slowed, this is an indication that the problem may be related to the solvent delivery system (pump).</li> <li>If the frequency of the baseline disturbance does not change when the flow rate is slowed, this is an indication that the problem is not pump-related and may be associated with column breakdown or contamination.</li> </ul> <div class="ts-question">Does the frequency of the baseline disturbance decrease when the flow rate decreases?</div> <div class="buttons"> <span class="btn-yes">[[Yes->Pressure Fluctuation]]</span> <span class="btn-no">[[No->Column Failure - Causes]]</span> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Lamp Energy</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/LampOnOff.jpg" alt="Lamp Energy"></div> The lamps are consumable and eventually become too weak to be effective. Click the appropriate lamp/detector link to learn how to check the reference intensities for that detector. <div class="ts-question">Are the reference intensities adequate?</div> <span class="btn-link">[[Lamp Intensity - LCsolution->Lamp Intensity - LCsolution]]</span> <div class="buttons"> <span class="btn-yes">[[Yes->Dirty Flow Cell]]</span> <span class="btn-no">[[No->Deuterium Lamp - SPD-M30A]]</span> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Lamp Intensity Check - LCsolution</h1> <div class="center"><iframe width="900" height="506" src="https://www.youtube.com/embed/rv4XK8kIcF8?rel=0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe></div> D2 - maximum intensity at or around 235 nm ≥ 7V Record the lamp intensities for future reference. <ol> <li>Use the supplied syringe and needle to fill the flow cell with degassed DI (deionized) water.</li> <li>Select START - PROGRAMS - LABSOLUTIONS - LCSOLUTION - LC MAINTENANCE TOOLS.</li> <li>The LC Tool Launcher is displayed. Select 'PDA Utility' and 'Instrument 1' and then press the Run button.</li> <li>The Login screen is displayed. Enter the User ID and Password and then press the OK button.</li> <li>The default UserID/password are as follows: UserID: admin Password: (none)</li> <li>The PDA Utility screen is displayed. Press the Wavelength Calibration button.</li> <li>The PDA Wavelength Calibration screen is displayed. Select Function - Check Light F7.</li> <li>The Adjust Light screen is displayed. Select either the D2 or the W lamp.</li> <li>Enter the wavelength used for the Intensity check.</li> <li>Enter the threshold to be used for the acceptance criterion. Press the OK button.</li> <li>The PDA Wavelength Calibration screen is displayed.</li> <li>Confirm that the voltage at the selected wavelength is larger than the set threshold.</li> </ol> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Stopping the Flow</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/LC-Pumpkey.jpg" alt="Stopping the Flow"></div> <h3>Determine whether the baseline disturbance is related to changes occurring in the flow cell or to a problem with the detector itself.</h3> Press the PUMP key to start and stop the pumping action. If the baseline disturbance continues after stopping the flow, the problem is most likely related to the detector or data system. If the baseline disturbance stops when the flow is stopped, the problem is most likely related to the sample stream. <div class="ts-question">Does the baseline disturbance persist when the flow is stopped?</div> <div class="buttons"> <span class="btn-yes">[[Yes->Lamp Energy]]</span> <span class="btn-no">[[No->Bubbles in the Flow Cell]]</span> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Troubleshooting Baseline Problems </h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/BaselineStability.jpg" alt="Troubleshooting Baseline Problems"></div> <h3>''Make a sample injecton to calculate the signal-to-noise ratio and determine if it is acceptable for your application.''</h3> * All baselines have an inherent amount of noise. Baseline noise is only a problem if the amount of noise is so excessive as to interfere with integration of the analyte of interest. Data systems often have an auto scale function that can make a normal baseline appear to be very noisy. * The signal to noise ratio is a measure of the Peak height with respect to the Noise height. This ratio can be increased by decreasing the noise or by increasing the peak (signal). * The sensitivity of the method and the scale of the chromatogram output must be determined before determining whether or not the noise is excessive. <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon">''NOTE: Calculating Signal-to-Noise Ratio'' The signal-to-noise ratio is calculated using the peak height of the noise and the peak height of the sample peak. EXAMPLE: Noise height 2mV - Sample height 10mV - The signal-to-noise ratio is 5. Typically, a signal-to-noise ratio of 3 is required for detection, and 10 for quantitation. <div class="ts-question">Is the magnitude of the baseline disturbance a problem for your application?</div><div class="buttons"> <span class="btn-yes">[[Yes->Baseline Disturbance]]</span> <span class="btn-no">[[No->Baseline is Not a Problem]]</span> </div> </div>
<div class="container"><h1 class="title">ZERO Key</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/Zero-key.jpg" alt="ZERO Key"></div> <h3>''Determine whether the data system is properly connected to the detector.''</h3> Press the ZERO key on the front of the detector to return the baseline to the zero position. The ZERO key is located to the right of the keypad and is functional even if the instrument is in REMOTE operation mode. <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon"><strong>NOTE: If necessary, the zero position can be adjusted using the BL OFS ITG (integrator) and BL OFS REC (recorder) screens in the Parameter Setting Group.</strong> <div class="ts-question">Does pressing the ZERO button cause a deflection in the baseline?</div> <div class="buttons"> <span class="btn-yes">[[Yes->Stopping the Flow]]</span> <span class="btn-no">[[No->Detector Connections]]</span> <span class="btn-back"><<back "Back">></span> </div> </div>
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Config.debug = false;
<div class="container"><h1 class="title">Flow Cell Cleaning - SPD-M30A</h1> <div class="center"><iframe width="900" height="506" src="https://www.youtube.com/embed/uD3DNEeCRA4?rel=0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe></div> <ol> <li>Open the doors.</li> <li>Loosen the clamp securing the flow line couplings and disconnect the flow lines.</li> <li>Disconnect the heater assembly connector.</li> <li>Loosen the screws and remove the flow cell.</li> <li>Attach a syringe filled with 2-propanol to the flow cell inlet.</li> <li>Flush the flow cell with 2-propanol. Repeat with mobile phase.</li> <li>Reinsert the flow cell and finger tighten the screws.</li> <li>Reconnect the heater assembly connector.</li> <li>Reconnect the flow lines and secure the couplings in the clamp.</li> <li>Close the doors.</li> </ol> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Mobile Phase Degassing</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/Degas.jpg" alt="Mobile Phase Degassing"></div> Bubbles are caused by dissolved gases. These bubbles can be responsible for pump malfunction and baseline noise. To prevent the formation of bubbles in the pump head and flow cell, a degassing method must be included in the mobile phase preparation. Some typical methods include vacuum filtration, vacuum sonication and helium sparging. In addition to conducting degassing during mobile phase preparation, it is also recommended that an on-line degassing unit be included in the system. The Shimadzu on-line degasser (DGU-20A3/20A5) provides continuous mobile phase degassing without changing the composition of the mobile phase. <br> <span class="btn-link">[[Back Pressure Tubing->Back Pressure Tubing]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Pressure Fluctuation</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/LC-Front.jpg" alt="Pressure Fluctuation"></div> <h3>Determine whether the solvent delivery is consistent. Monitor the pressure value on the pump display.</h3>When the solvent delivery system is working properly, the pressure indicator will display a very stable value. When the pump displays a large pressure fluctuation, it is an indication that the actual delivery flow rate is changing. For example, a lower pressure or wildly fluctuating pressure indicates a lower or fluctuating flow rate and will result in longer and inconsistent retention times. If the pressure is lower than expected or fluctuating, pump troubleshooting will be required. <div class="ts-question">Is the pressure value fluctuating by about 5%?</div><div class="buttons"> <span class="btn-yes"><a href="https://www.ssi.shimadzu.com/service-support/virtual-advisor/nexera/advanced-troubleshooting/troubleshooting-the-pump/index.html">Troubleshoot the Pump</a></span> <span class="btn-no">[[No->Column or Solvent]]</span> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Column Failure - Causes</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/ColumnParam.jpg" alt="Column Failure - Causes"></div> By monitoring certain column parameters, it is possible to determine when a column is starting to deteriorate and might need to be replaced. The following column parameters are important to monitor for each column. <ul><li>Theoretical plates</li><li>Capacity factor</li><li>Selectivity</li><li>Tailing factor</li><li>Pressure</li> </ul> There are three main reasons for column failure. Select from the items below for more information. <ul> <li>Loss of the bonded phase</li><li>Formation of voids</li><li>Build-up of contamination</li> </ul> <span class="btn-link">[[Bonded Phase->Bonded Phase]]</span><br> <span class="btn-link">[[Void->Void]]</span> <br> <span class="btn-link">[[Contamination->Contamination]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Column or Solvent</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/Column-vs-solvent.jpg" alt="Column or Solvent"></div> <h3>Finally, you must be determined whether the baseline disturbance is solvent-related or column-related. Replace the column with a flow line union.</h3> By this point in the troubleshooting process, the data system, detector and pump have all been ruled out as the cause of the baseline disturbance. By removing the column and replacing it with a flow line union, it is possible to determine whether the column is the source of the disturbance. <ul> <li>If the baseline disturbance continues after the column is removed, it must be concluded that the disturbance is related to the mobile phase or the gradient mixing procedure.</li> <li>If the baseline disturbance ceases when the column is removed, the column is the likely cause of the disturbance.</li> </ul> <div class="ts-question">Does the baseline disturbance persist with the column removed?</div> <div class="buttons"> <span class="btn-yes">[[Yes->Solvent Choice]]</span> <span class="btn-no">[[No->Column Failure - Causes]]</span> <span class="btn-back"><<back "Back">></span> </div> </div>
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<div class="container"><h1 class="title">Column Failure - Bonded Phase</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/BondedPhase.jpg" alt="Column Failure - Bonded Phase"></div> Consistently decreasing retention times may be caused by a loss of bonded phase from the column's silica support. Hydrolysis of the bonded phase is most severe in systems with a mobile phase pH of less than 3. As a column deteriorates, retention times and resolution decrease; peak tailing may also become evident. <span class="btn-link">[[Causes->Column Failure - Causes]]</span><br> <span class="btn-link">[[Void->Void]]</span> <br> <span class="btn-link">[[Contamination->Contamination]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Column Failure - Void</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/ColumnVoid.jpg" alt="Column Failure - Void"></div> The most common causes of voids at the head of the column are violent pressure changes, gradual settling in poorly packed columns and high pH dissolving the silica packing. As a void forms at the head of the column, efficiency (N) drops, resolution decreases and peaks broaden, split or begin to tail. <span class="btn-link">[[Causes->Column Failure - Causes]]</span><br> <span class="btn-link">[[Bonded Phase->Bonded Phase]]</span> <br> <span class="btn-link">[[Contamination->Contamination]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Column Failure - Contamination</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/ColumnContamination.jpg" alt="Column Failure - Contamination"></div> Column contamination is caused by a build-up of retained material on the stationary phase or by plugging of the column frit and packing by particulate matter, precipitated sample or buffer. Contamination can lead to shifting retention times, loss of resolution and poor peak shape. <img class="warning" style="float: left;" src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/virtual-advisor-warning-icon.png" alt="warning-icon"><strong>NOTE: Filtering of all sample solution is highly recommended. Avoid injecting a cloudy sample solution.</strong> <br> <span class="btn-link">[[Causes->Column Failure - Causes]]</span><br> <span class="btn-link">[[Bonded Phase->Bonded Phase]]</span> <br> <span class="btn-link">[[Column Failure - Void->Void]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Solvent Choice</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/SolventChoice.jpg" alt="Solvent Choice"></div> Choosing the correct solvents of suitable quality is the first step in the process. It is also important to use a consistent solvent supplier, because solvents from different suppliers may vary in purity specifications. Always use solvents and reagents (including water) that are specified HPLC grade or better. <span class="btn-link">[[Solvent Preparation->Solvent Preparation]]</span><br> <span class="btn-link">[[Solvent Delivery->Solvent Delivery]]</span> <br> <span class="btn-link">[[Solvent Mixing->Solvent Mixing]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Solvent Preparation</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/SolventPrep.jpg" alt="Solvent Preparation"></div> Whether preparing premixed isocratic mobile phases or non-mixed gradient solvents, care should be taken in the preparation process. Use caution to ensure that clean containers are used for solvent reservoirs. Employ a methodical process for buffer preparation to ensure repeatable preparations. All solvents should be filtered through a 0.45 µm (or smaller) pore size. Incorporate a thorough degassing process in the preparation process. <span class="btn-link">[[Solvent Choice->Solvent Choice]]</span><br> <span class="btn-link">[[Solvent Delivery->Solvent Delivery]]</span> <br> <span class="btn-link">[[Solvent Mixing->Solvent Mixing]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Solvent Delivery</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/LC-PressDisplay.jpg" alt="Solvent Delivery"></div> It is important to use the designated solvent delivery type. Results may vary if results are compared from systems that incorporate different pump types. Differences in high-pressure and low-pressure gradient elution processes make it impossible to interchange them. <span class="btn-link">[[Solvent Choice->Solvent Choice]]</span><br> <span class="btn-link">[[Solvent Preparation->Solvent Preparation]]</span> <br> <span class="btn-link">[[Solvent Mixing->Solvent Mixing]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>
<div class="container"><h1 class="title">Solvent Mixing</h1> <div class="center"><img src="https://www.ssi.shimadzu.com/sites/ssi.shimadzu.com/files/support/virtual-advisors/nexera/troubleshooting-baseline-problems/SolventMix.jpg" alt="Solvent Mixing"></div> It is necessary to incorporate a solvent mixing chamber for any gradient elutions. Mixing chambers create a homogeneous mixture from multiple solvent reservoirs. These chambers are necessary in any system used to blend solvents, even those performing isocratic separations. <span class="btn-link">[[Solvent Choice->Solvent Choice]]</span><br> <span class="btn-link">[[Solvent Preparation->Solvent Preparation]]</span> <br> <span class="btn-link">[[Solvent Delivery->Solvent Delivery]]</span> <div class="buttons"> <span class="btn-back"><<back "Back">></span> </div> </div>