Agilent 355 Sulfur and 255 Nitrogen Chemiluminescence Detectors Operation and Maintenance Manual Agilent Technologies
Notices © Agilent Technologies, Inc. 2012 Manual Part Number No part of this manual may be reproduced in any form or by any means (including electronic storage and retrieval or translation into a foreign language) without prior agreement and written consent from Agilent Technologies, Inc. as governed by United States and international copyright laws. G6600-90006 Acknowledgements Agilent Technologies, Inc.
Warnings English WA R N I N G This symbol on the instrument indicates that the user should refer to the manual for operating instructions. WA R N I N G Any operation requiring access to the inside of the equipment, could result in injury. To avoid potentially dangerous shock, disconnect from power supply before opening the equipment. WA R N I N G For continued protection against fire hazard replace fuse with same type and rating.
WA R N I N G Ozone is a hazardous gas and a strong oxidant. Exposure to ozone should be minimized by using the instrument in a well-ventilated area and by venting the exhaust of the vacuum pump to a fume hood. The ozone generator should be turned off when the instrument is not in use. WA R N I N G Burner temperature Is extremely hot. Do not touch. Allow to cool before servicing. WA R N I N G Hydrogen is an extremely flammable gas. Use appropriate care when handling.
Español WA R N I N G Cualquier operación que requiera acceso al interior del equipo, puede causar una lesión. Para evitar peligros potenciales, desconectarlo de la alimentación a red antes de abrir el equipo. WA R N I N G Para protección contínua contra el peligro de fuego, sustituir el fusible por uno del mismo tipo y características. WA R N I N G Este símbolo en el instrumento indica que el usuario debería referirse al manual para instrucciones de funcionamiento.
Français 6 WA R N I N G Chaque opération à l'intérieur de l'appareil, peut causer du préjudice. Afin d'éviter un shock qui pourrait être dangereux, disconnectez l'appareil du réseau avant de l'ouvrir. WA R N I N G Afin de protéger l'appareil continuellement contre l'incendie, échangez le fusible par un fusible du même type et valeur. WA R N I N G Le symbol indique que l'utilisateur doit consulter le manuel d'instructions. WA R N I N G Ceci est un produit de Classe de sécurité I.
Deutsch WA R N I N G Vor dem Öffnen des Gerätes Netzstecker ziehen! WA R N I N G Für kontinuierlichen Schutz gegen Brandgefahr dürfen bei Sicherungswechsel nur Sicherungen der gleichen Stärke verwendet werden! WA R N I N G Dieses Symbol auf dem Gerät weist darauf hin, dass der Anwender zuerst das entsprechende Kapitel in der Bedienungsanleitung lesen sollte. WA R N I N G Dies ist ein Gerät der Sicherheitsklasse I und darf nur mit einem Netzkabel mit Schutzleiter betrieben werden.
Italiano 8 WA R N I N G Qualsiasi intervento debba essere effettuato sullo strumento può essere potenzialmente pericoloso a causa della corrente elettrica. Il cavo di alimentazione deve essere staccato dallo strumento prima della sua apertura. WA R N I N G Per la protezione da rischi da incendio in seguito a corto circuito, sostituire I fusibili di protezione con quelli dello stesso tipo e caratteristiche.
Dutch WA R N I N G Iedere handeling binnenin het toestel kan beschadiging veroorzaken. Om iedere mogelijk gevaarlijke shock te vermijden moet de aansluiting met het net verbroken worden, vóór het openen van het toestel. WA R N I N G Voor een continue bescherming tegen brandgevaar, vervang de zekering door een zekering van hetzelfde type en waarde. WA R N I N G Het symbool geeft aan dat de gebruiker de instructies in de handleiding moet raadplegen.
The following symbols are used on the equipment: 10 Caution - Refer to manual for operating instructions Caution - Risk of electrical shock. Caution - Hot surface. Atención - Ver documentación pertinente. Atención - Riesgo de sacudidas Atención - Superficie caliente. eléctricas. Attention - Consultez les ocuments d'accomagnement. Attention - Risque de choc électrique. Attention - Surface brûlante. Vorsicht - Siehe beiliegende Unterlagen. Vorsicht - Risiko eines Elektroschocks.
Contents 1 Introduction 2 System Description Specifications 20 Technical Information — 355 SCD Technical Information — 255 NCD Physical Specifications 21 20 20 Theory of Operation 23 Sulfur Chemiluminescence Detector 23 Nitrogen Chemiluminescence Detector 23 Dual Plasma Controller 24 Description of Major Components 25 Dual Plasma Burner 25 Figure 1. Cross-Section of the Dual Plasma Burner for the 355 SCD Figure 2.
3 Installation Overview 40 Step 1: Selecting a Location 41 Power Requirements 41 Figure 10. Drawing of the Detector with Dual Plasma Burner and Controller Environmental Considerations 42 Combustion Gas Requirements 42 Step 2: Unpack and Inspect the Instrument Required Installation Tools 45 45 Step 3: Set Up the Vacuum Pump 46 Installing the Edwards RV5 Pump Oil-Sealed Vacuum Pump 46 Figure 11. RV5 Oil-Sealed Vacuum Pump and Associated Traps (Front Side) Figure 12.
Packed Columns and Columns with an Outside Diameter > 0.8 mm Step 10: Install the Transfer Line 61 62 4 Front Panel Controls and Initial Startup Detector Front Panel Controls 64 Figure 21. Front Panel Controls 64 Power Controls 64 Display Output Controls 65 Signal Controls 65 Dual Plasma Controller Controls 66 Figure 22.
6 Maintenance Pump Maintenance 82 Table 3. Operating Life of Components for Edwards RV5 Vacuum Pump Cleaning the Detector 83 Changing the Oil Mist Filter (RV5) 84 Reaction Cell Cleaning 85 Figure 23. Reaction Cell, PMT Housing and PMT Socket Figure 24. Reaction Cell 86 Flow Sensor Calibration Detector Sensitivity 82 86 88 89 Assembling the Dual Plasma Burner for Component Replacement with the SCD 90 Figure 25. Ferrule Placement on Lower Burner Tube 90 Figure 26.
7 Troubleshooting Solving Detector Problems 106 Power Problems 107 Detector Fuse 107 Vacuum Pump Fuse 107 Dual Plasma Controller Fuses 107 Table 4. Fuses for 100 V, 120 V and 230 V Versions of 355 SCD and 255 NCD Figure 47. Fuse Positions on the Power Supply Board 108 108 Ozone Generation Problems 109 Ozone Generator 109 High Voltage Transformer 109 Plugged Restrictor Lines 110 Response Problems 111 Temperature Reading Problems 112 Diagnosing General Problems 113 Table 5.
Operation and Maintenance Manual
Agilent 355 Sulfur and 255 Nitrogen Chemiluminescence Detectors Operation and Maintenance Manual 1 Introduction This manual will guide you in the installation, operation, and troubleshooting of the Agilent 355 Sulfur Chemiluminescence Detector (SCD) and the Agilent 255 Nitrogen Chemiluminescence Detector (NCD). This manual is intended for use with the Agilent 355 SCD or 255 NCD with the Dual Plasma Burner and Controller.
Operation and Maintenance Manual
Agilent 355 Sulfur and 255 Nitrogen Chemiluminescence Detectors Operation and Maintenance Manual 2 System Description Specifications 20 Theory of Operation 23 Description of Major Components 25 Agilent Technologies 19
Specifications Technical Information — 355 SCD Sensitivity* Typical < 0.5 pg S/second (signal to noise 3.
Repeatability* <1.
Dual Plasma Burner Height: 12.3 in (31.2 cm) Diameter: 4.0 in (10.2 cm) Weight: 1.9 lbs (0.9 kg) Oil Sealed Vacuum Pump (RV5) Height: 10.3 in (26.1 cm) Width: 6.0 in (15.2 cm) Depth: 16.9 in (43.0 cm) Weight: 47.3 lbs (21.5 kg) or 22 Oil Free Dry Piston Pump Height: 12.0 in (30 cm) Width: 9.0 in (22.9 cm) Depth: 14.0 in (35.6 cm) Weight: 29.9 lbs (13.
Theory of Operation Sulfur Chemiluminescence Detector The Agilent model 355 Sulfur Chemiluminescence Detector (SCD) is a sulfur-selective detector for gas chromatography.
Dual Plasma Controller The Dual Plasma Controller provides all operational parameters of the Dual Plasma Burner except for the Detector base temperature. The Detector base temperature is controlled by circuitry in the GC. Parameters monitored or regulated by the Controller include Burner temperature, Burner temperature set-point, hydrogen and oxidant flow rates, and Burner pressure. The temperature set-point, actual pressure, oxidant and hydrogen flow rates are displayed by rotation of a 4-position switch.
Description of Major Components Dual Plasma Burner The Dual Plasma Burner consists of a tower assembly that contains an outer sheath for burn protection, a heating element, thermocouple, and combustion tubes. In the SCD, conversion of sulfur containing compounds to SO occurs within the ceramic reaction chamber housed in the Burner assembly and potentially interfering hydrocarbons are oxidized to CO2 and H2O, with air as the oxidant. In the NCD, oxygen is used as the oxidant.
Figure 1 26 Cross-Section of the Dual Plasma Burner for the 355 SCD Operation and Maintenance Manual
Figure 2 Cross-Section of the Dual Plasma Burner for the 255 NCD Dual Plasma Controller The Dual Plasma Controller powers the Dual Plasma Burner and supplies its gases. Hydrogen and oxidant should be provided at 25 psig (1.72 bar) and the Controller is plugged into an appropriate AC electrical outlet. WA R N I N G Exceeding the gas inlet pressure of 25 psig (1.72 bar) may damage the hydrogen and oxidant sensors or burst their connective tubing.
temperature, hydrogen and oxidant flow rates, and Burner pressure. The temperature, actual pressure, oxidant and hydrogen flow rates are selected for display by rotation of a 4-position control knob. Power, valve operation, temperature within set-point range and fault conditions are indicated with LED illumination on the front display panel. The Dual Plasma Controller incorporates several safety features.
10 3 4 5 6 6 2 7 8 1. Ozone Generator 1 2. High Voltage Transformer 6. Vacuum Line 7. Particulate Filter 3. Photomultiplier Tube Socket 8. Pre-Ozone Restrictor 4. Photomultiplier Housing 5. Reaction Cell Figure 3 9 9. Post-Ozone Restrictor 10.
18 17 11 IN OFST RV1 I OUT OFST RV2 AMP 1 TP8 TP10 TP12 TP2 TP13 OUT TP5 TP4TP6 TP7 13 TP2 TP4 TP12 TP1 16 TP8 TP13 GND TP6 12 TP3 TP5 TP7 TP16 TP14 TP9 TP15 TP10 HV/100 TP11 TO FRONT PANEL TP3 ALCO TP1 TP9 USA TP11 SIEVERS RESEARCH ELECTRONICS RV1 HV OZONE PUMP 15 LOAD PUMP P4 OUT NEUT P5 LOAD P6 NEUT P7 LINE P2 OZONE GEN AC WHT WHT NEUT P3 WHT 14 Figure 4 30 11. Amplifier Cable 15. Fuses 12. HV Cable 16. Pressure Regulator 13. PMT Amplifier 14.
Figure 5 255 NCD Left Side View Operation and Maintenance Manual 31
Figure 6 255 NCD Right Side View Pressure Transducer Vacuum in the reaction cell is measured using a pressure transducer. The pressure of the reaction cell can be monitored from the front panel and will typically range from 5 to 10 torr depending on the type of vacuum pump used, condition of the chemical (ozone) trap, ceramic tube position and the condition of the combustion chamber. The range of response is from 0 to 760 torr.
• Collection and transfer of the combustion gases from the Burner to the reaction cell. • Transfer of ozone from the ozone generator to the reaction cell. • Reduction of non-radiative collisional quenching of the emitting species in the chemiluminescent reaction cell. The higher vacuum produced by the oil-sealed rotary pump facilitates a shorter residence time in the reaction chamber, and therefore reduces the incidence of collisional relaxation of the excited SO2.
directly in front of the photomultiplier tube (PMT). A red cut-off filter between the reaction cell and the PMT selectivity transmits the light from the nitric oxide and ozone reaction. Efficient combustion in the ceramic tubes and the red cut-off filter eliminate interference from non-nitrogen containing analytes (sulfur dioxide, alkenes, olefins) that have chemiluminescence reactions with ozone.
25 psig max Mass flow Mass flow P S 25 psig max NC F.C. S NC Air H2 F.C.
25 psig max Mass flow Mass flow P S 25 psig max NC F.C. S NC F.C.
Mass flow Mass flow P S F.C. S NC F.C.
Operation and Maintenance Manual
Agilent 355 Sulfur and 255 Nitrogen Chemiluminescence Detectors Operation and Maintenance Manual 3 Installation Overview 40 Step 1: Selecting a Location 41 Step 2: Unpack and Inspect the Instrument 45 Step 3: Set Up the Vacuum Pump 46 Step 4: Connect the Power Cord 56 Step 5: Install the Dry Compressed Air or O2 Supply 57 Step 6: Install the Signal Output Cables 58 Step 7: Install the Dual Plasma Burner 59 Step 8: Install the Dual Plasma Controller 60 Step 9: Install Column Connections 61 Step 10: Install
Overview Installation and start-up of the Agilent 355 SCD or 255 NCD by a qualified Agilent Service technician is recommended. If you choose to install the detector yourself, carefully read all of this chapter prior to installation of the instrument. Although every reasonable safeguard against shipping damage has been taken, product damage may still occur due to excessive mishandling. If obvious damage has occurred during shipment, contact Agilent.
Step 1: Selecting a Location The instrument should be placed on a clean, unobstructed surface approximately 22" (55 cm) deep by 10" (24 cm) wide that can support 44 pounds (19.9 kg) in addition to existing equipment. Figure 10 illustrates the relationship between the major system components. To facilitate proper heat dissipation, an additional 1-2" (2.5-5.0 cm) should be available at the rear and on both sides of the instrument.
Figure 10 Drawing of the Detector with Dual Plasma Burner and Controller Environmental Considerations The instrument should be operated in an environment which is comfortable for human habitation with reasonably constant temperature and humidity. Operation of the instrument at elevated temperatures (>30 °C) may result in an increased background noise from the photomultiplier tube.
with air as the oxidant in the SCD and oxygen as the oxidant in the NCD. For the SCD, detector gases must be sulfur free (<1ppb) for proper Detector operation. In general, bottled air is preferred to “house” air from a compressor because compressors tend to generate lower quality air. In addition, pressure fluctuations induced by the air generator may be detrimental to Detector performance. For the NCD and GC, use gases that are low in nitrogen and total hydrocarbons.
WA R N I N G Secure all gas cylinders to an immovable structure or permanent wall. Store compressed gases in accordance with all safety codes. WA R N I N G Wear eye protection when using compressed gas to avoid possible eye injury. Venting Gases During normal operation of the GC with the SCD, NCD, FID, other detectors and split/splitless inlet purge, some of the carrier gas and sample vents outside the GC. In addition, the vacuum pump will vent a small amount of ozone and other combustion products.
Step 2: Unpack and Inspect the Instrument Before unpacking boxes, inspect them for signs of physical damage. If damage is observed, photographs should be taken in order to make a claim with the carrier should any equipment damage be found. Check contents of boxes against the shipping documents. Contact Agilent as soon as possible should a discrepancy be found.
Step 3: Set Up the Vacuum Pump Initial connections require access to the rear of the Detector and the vacuum pump. Follow the installation instructions for either the RV5 Edwards pump or the oil-free dry piston pump, depending on your configuration. WA R N I N G Exhaust gases from the pump should be vented to a fume hood to eliminate any potential hazard.
11 Remove the drain plug and the bonded seal from the oil mist filter. The bonded seal looks like a metal washer with a black inner o-ring. 12 Install the bonded seal to the oil mist filter drain adapter. The drain adapter looks like a drain plug with a small plastic nozzle. 13 Screw the black drain adapter and bonded seal into the oil mist filter. 14 Remove the plastic protective cover from the pump exhaust port. Place the centering o-ring on the pump exhaust port (see Figure 13).
26 The vacuum pump should be placed within approximately 3 feet of the Detector (elevation not important), in order to connect the vacuum hose from the back of the Detector to the chemical trap. A hose clamp should be placed over the hose, and the hose should be connected to the straight end of the chemical trap. Tighten the hose clamp securely. WA R N I N G Vent the exhaust gas from the vacuum pump to fume hood to eliminate any potential hazard.
Chemical Trap Ballast control Mounting Bracket Oil return line Oil mist filter Power switch EDWARDS Edwards Mode selector Figure 11 RV5 Oil-Sealed Vacuum Pump and Associated Traps (Front Side) Chemical Trap Ballast Control Oil Mist Filter Barbed Vacuum Inlet Oil Return Line EDWARDS Power Plug 5 Figure 12 RV5 Oil-Sealed Vacuum Pump and Associated Traps (Back Side) Operation and Maintenance Manual 49
Pump exhaust Gas ballast Inlet & valve Retractable handle Oil fill caps Pump inlet Chemical Trap Figure 13 RV5 Oil- Sealed Vacuum Pump and Associated Traps (Top) NOTE 50 Sometimes water condensation and accumulation are visible in the exhaust line. This is normal. However, do not allow water to continue to accumulate after approximately one week of operation. Significant water accumulation may indicate improper pump operation, an improperly vented exhaust line, or a Burner leak.
Figure 14 RV-5 Oil-S ealed Vacuum Pump Exhaust Line Setting the Gas Ballast Position (RV5) Set the mode selector halfway between the High Vacuum mode, the small symbol (see Figure 14) and the High Throughput mode. Do not set the mode selector to the High Throughput mode, the large symbol. The RV5 vacuum pump and the Oil Drain Kit with ballast flow control ensure the vacuum pump operates continuously with a gas ballast flow. The purpose of the ballast control is to sweep ambient air into the pump oil.
• To select no gas ballast flow (not recommended), turn the restrictor plate so that none of the indentations are aligned with the indentation on the side of the oil return assembly. • To select low gas ballast flow, turn the restrictor plate so that the single indentation on the restrictor plate is aligned with the indentation on the side of the oil return assembly.
10 Tighten the hose clamp located on the plastic tube and the elbow barb end of the Chemical Trap. 11 Remove the plastic cap from the inlet end of the Chemical Trap. Taking the clear end of the vacuum hose and another hose clamp attach the vacuum hose to the inlet end of the Chemical Trap and tighten the hose clamp. 12 Attach the black end of the vacuum hose to the barb fitting located on the back of the Detector box and tighten the last hose clamp onto it to make this connection.
Figure 15 The Welch Dry Piston Pump Screws Restrictor Plate Indentation (Alignment Guide) Indentation (Low Ballast) Indentation (High Ballast) Figure 16 Oil Drain Kit with Ballast Control 6 Turn the switch on the vacuum pump to the On position.
Note the position of the oil level in the window after operating the pump for several hours. For the next several days of operation, recheck the oil level daily. If the oil level is increasing, water is accumulating in the oil reservoir. Confirm that the water vapor is properly being expelled from the oil mist filter. If the oil level is dropping, excess air flow through the pump is forcing oil out of the vacuum pump.
Step 4: Connect the Power Cord Connect the pump power cord to the female socket on the back of the Detector (see Figure 17). The pump has an On/Off switch located on the electrical motor and this switch should be turned On. Do not connect to the AC power supply at this point in the installation procedure.
Step 5: Install the Dry Compressed Air or O2 Supply Connect a 1/8" OD PTFE (PFA) line fitted with a 1/8" brass Swagelok nut from the AIR INLET at the rear of the Detector (see Figure 17) to a supply of dry compressed air or oxygen. The air regulator located inside the front door of the Detector should be set to approximately 3-6 psi.
Step 6: Install the Signal Output Cables Signal output cables are available from Agilent as standard equipment and can be used with most data systems. Confirm that the output cable supplied is correct for your system. A standard cable fitted with two crimp lug connectors is supplied for use with most integrators, recorders or data systems. Attach the BNC connector end of the recorder cable to the matching output connector, labeled RECORDER OUTPUT, on the back of the SCD (see Figure 17).
Step 7: Install the Dual Plasma Burner Remove the cover plates from the Detector area of the GC to expose the hole into the oven through which a Detector is normally mounted. If the GC has more than one available Detector position, pick the most convenient one. Prepare the GC by cutting the inside liner and top liner per Figure 17. Note that mounting fastener patterns will vary by GC manufacturer.
Step 8: Install the Dual Plasma Controller Position the Controller such that the gas lines from the Burner can be easily attached to the back of the Controller. Connect the Controller to both a hydrogen source and an oxidant source, per Step 1. Connect the gas supplies to the 1/8" bulkhead unions marked "Oxidizer Inlet" and "Hydrogen Inlet." Clean copper tubing (1/8" OD) is recommended.
Step 9: Install Column Connections The Burner operates under reduced pressure and there will be a slight vacuum on the end of the column. If a higher outlet pressure for the column outlet is desired, fused silica capillary restrictors may be attached to the end of the analytical column (both capillary and packed) prior to making the Detector connection. Capillary Columns Place the column nut over the end of the capillary column. Place the appropriate fused silica adapter ferrule onto column.
Step 10: Install the Transfer Line Connect the black transfer line (extending from the side of the Detector) to the top connector on the Burner and tighten with a 3/8" open-end and 7/16" open-end wrench (backing up the union on top of the Burner to prevent its position form slipping).
Agilent 355 Sulfur and 255 Nitrogen Chemiluminescence Detectors Operation and Maintenance Manual 4 Front Panel Controls and Initial Startup Detector Front Panel Controls 64 Detector Interface Setup 69 Agilent Technologies 63
Detector Front Panel Controls As illustrated in Figure 21, the front panel is divided into three sections: signal control, display output control, and power control. Each section is described below. All the front panel LEDs are red in the ON mode and darkened in the OFF mode except for POWER. This LED toggles green for ON and red for STANDBY. In STANDBY mode, the front panel display and high voltage to the photomultiplier tube (PMT) are turned off.
Turns ozone generator ON or OFF. Functions in both ON and STANDBY modes if the pump is producing sufficient vacuum. Display Output Controls Controls the range of the front panel display between high sensitivity (0.1-200mV) and low sensitivity (0-2V). Does not affect recorder output signal. Displays the output signal of the SCD in millivolts. (Note: Changing the output range of the SCD by adjusting the recorder switch on the back panel does not change the range of the display.
The baseline signal from the SCD and NCD can be adjusted from 0 to ±1% of the full scale recorder output using the offset control. (e.g., +10 mV to -10 mV for a 1 V full scale setting). This control can be used to offset the background signal. Dual Plasma Controller Controls The Agilent Dual Plasma Controller provides easy access to basic settings. Figure 22 Dual Plasma Controller Front Panel 66 Oxidizer and Hydrogen Control Knobs Allow you to adjust the oxidizer and hydrogen flow rate.
Controller Status Lights Illuminate to reflect current status. The Power LED indicates power is on; the Heater LED indicates temperature set point has been obtained; the Valves LED indicates the solenoid valves open; and the Fault LED indicates a drop in pressure or excessive temperature (see Chapter 7, “Troubleshooting” for details).
Reaction cell pressure, with air to ozone generator OFF (0 psi setting on internal regulator) and transfer line capped: ___________________ torr Tighten connections if necessary and check to make sure pressure stabilizes in the expected region. If proper pressure is not obtained contact Agilent for assistance. If the reaction cell pressure is within the expected range, record the value, reset the internal air regulator to 3-6 psi, turn the pump OFF and proceed with the recorder test.
Detector Interface Setup Initial Checkout Careful attention to eliminating leaks in the Detector interface will lead to better Detector sensitivity and easier troubleshooting if problems develop. 1 Check that the gas connections have been made correctly and that they are tight. 2 Plug the 3-prong connector for power on the Controller into a 100-volt, 50/60 Hz, 115-volt, 50/60-Hz or 230-volt, 50/60 Hz AC outlet. 3 Connect the oxidant delivery line to the oxidant inlet nut on the Burner.
Monitoring Oxidizer and Hydrogen Flow with the Dual Plasma Controller Hydrogen will flow to the Burner only if the temperature is above 325 °C and the pressure of the Burner is <575 torr. Turn ON the vacuum pump at the Detector and the power to the Dual Plasma Controller. The power LED should illuminate. When the temperature reaches approximately 325 °C, the valve’s LED should illuminate, indicating hydrogen and oxidant flow. Use the Controller display knobs to select display of oxidizer or hydrogen flow.
Agilent 355 Sulfur and 255 Nitrogen Chemiluminescence Detectors Operation and Maintenance Manual 5 Operation Start-Up Procedure 72 Detector Operation 73 Typical Operating Conditions 75 Detection Limits 76 Instrument Shut-Down 77 Special Operating Modes 78 Agilent Technologies 71
Start-Up Procedure 1 Turn on the GC and set the carrier flow rate. 2 Turn on the hydrogen and oxygen to the Dual Plasma Controller. 3 Turn the Detector from STANDBY to ON. 4 Press the PUMP button until the red LED illuminates. Make sure the vacuum pump is running. 5 Turn on the oxygen to the ozone generator and set the regulator inside the front door of the Detector to between 3 and 6 psig. 6 Allow the system to evacuate for approximately 1 minute before turning on the ozone at the front panel.
Detector Operation Detector Stability and Response The time required for system stabilization varies depending on the application, system cleanliness, presence of active sites and other factors. Useful results could be generated within 30 minutes of start-up, especially with a previously operated system. A longer stabilization time is likely to be required upon changing critical system components, such as the combustion tubes or the GC column.
Contaminated Gases The use of clean gases for the 355 SCD is essential for optimal performance. High purity gases (99.999% pure or better) are advised. Sulfur and other contaminants from gases may accumulate in the column and bleed out over time desensitizing the tubes and causing elevated baselines. The use of sulfur traps is highly recommended for all gases. Fluctuating Pressures Fluctuations in pressure, especially from gas generators, will affect Detector response.
Typical Operating Conditions The Controller is calibrated at the factory for flow rates to deliver gas in sccm units. The following table summarizes the typical operating conditions: Table 1 Typical Operating Conditions Condition SCD NCD * Detector Pressure (Torr) 4-8 (6-12 ) 4-10 Dual Plasma Controller Pressure (Torr) 300-400 100-250 Burner Temperature (°C) 800 900-950 Hydrogen Flow Rate (sccm) 40-50 4-6 Oxidant Flow Rate (sccm) 60-65 (air) 8-12 (oxygen) Background Noise (mV) 0.3-2.
Detection Limits The following table lists the detection limits which can be expected for typical chromatographic conditions, assuming proper operation of the Detector and chromatographic systems. Table 2 Expected Detection Limits for Chromatographic Conditions Type of Injection Volume Column Detection Limit Per Compound as Sulfur Liquid, Split 1:10 1 µL Capillary 0.32 mm ID 50 parts per billion Liquid, Split 1:100 1 µL Capillary 0.32 mm ID 0.
Instrument Shut-Down Daily Shutdown 1 Toggle off the ozone generator. 2 Turn off the air regulator (counter-clockwise), located inside Detector door. 3 Toggle power to "stand-by." 4 Leave the vacuum pump and Dual Plasma Controller operating at all times. Complete Shutdown 1 Toggle off the ozone generator. 2 Turn off the air regulator (counter-clockwise), located inside Detector door. 3 Toggle power to STANDBY. 4 Turn off power to the Dual Plasma Controller.
Special Operating Modes Using the 255 NCD in Nitrosamine Mode By default, the 255 NCD is configured to detect nitrogen. To change from nitrogen to nitrosamine mode, first turn off and unplug the Controller. Remove the cover, find jumper P6 and the positions labelled High Setpoint and Low Setpoint located on the printed circuit board near the left front of the Controller. Move the jumper position from the High Setpoint to the Low Setpoint position.
can be achieved by eliminating the lower plasma. This is accomplished by plugging the side port of the splitter fitting and teeing the air into the lower hydrogen line, much like the configuration used for Nitrosamine analysis as shown in Figure 9. A slightly lower air flow rate, such as 40 SCCM and a hydrogen flow rate of around 60 SCCM is used. Sensitivity of around 0.1 pg S/sec or less should be readily achievable.
Operation and Maintenance Manual
Agilent 355 Sulfur and 255 Nitrogen Chemiluminescence Detectors Operation and Maintenance Manual 6 Maintenance Pump Maintenance 82 Cleaning the Detector 83 Changing the Oil Mist Filter (RV5) 84 Reaction Cell Cleaning 85 Flow Sensor Calibration 88 Detector Sensitivity 89 Assembling the Dual Plasma Burner for Component Replacement with the SCD 90 Assembling the Dual Plasma Burner for Component Replacement with the NCD 95 Tube Replacement for the SCD 98 Tube Replacement for the NCD 102 Agilent Technologies
Pump Maintenance To maintain optimum performance of the Agilent 355 SCD and 255 NCD, routine replacement of the chemical trap (for ozone destruction), oil coalescing filter and oil (Edwards oil-sealed pump only) is necessary. Refer to Table 3 for the expected life span of each replacement part or material. It is beneficial to keep a maintenance log that tracks when maintenance is performed and any instrument or operational changes that might impact performance.
Cleaning the Detector You can clean the external housing of the Detector with a damp cloth using water or non-abrasive cleaners. Turn off power to the Detector and disconnect it from main power prior to cleaning. Do not spray liquids directly on the Detector. Wipe dry with a clean, soft cloth. No cleaning agents which could cause a hazard as a result of reaction with the Burner unit are to be used in cleaning the instrument.
Changing the Oil Mist Filter (RV5) The oil mist filter on the RV5 pump has two components: the charcoal odor filter and the oil coalescing filter element. To replace the filters, disassemble the oil mist filter assembly with the 4 mm long-handled allen wrench (provided). The smaller charcoal odor filter sits on top of the larger oil coalescing filter element.
Reaction Cell Cleaning Over time, the reaction cell and UV pass filter (SCD) or IR pass filter (NCD) will develop a build-up of material which should be removed for optimum sensitivity. The cleaning schedule depends upon Detector use and the nature of the analyses; however, it is recommended the cell should be cleaned annually. The cleaning procedure requires removal of the photomultiplier tube (PMT) from the Detector, and special precautions are required to prevent damage to the PMT.
Figure 23 Reaction Cell, PMT Housing and PMT Socket Figure 24 Reaction Cell 6 Use a 7/64" Allen wrench to remove the three mounting screws from the reaction cell. Slowly pull the reaction cell back from the PMT housing. The optical filter is located between the reaction cell and the PMT housing. Remove the optical filter from the housing by tipping up the back of the Detector, if necessary, and allow the filter to fall onto a soft cloth. 7 Inspect the o-rings and replace them if they show any wear.
8 Clean any deposits on the optical filter using a soft cloth or Kimwipe dampened with methanol or deionized (DI) water. Do not leave fingerprints or fibers on the cleaned filter. Deposits inside the reaction cell can be cleaned in the same manner, however, care must be taken to avoid bending the ozone inlet tube that extends into the cell. 9 Reseat the pass filter into the PMT housing. Confirm that the two o-rings around the reaction cell are properly seated in the O-ring grooves (see Figure 24).
Flow Sensor Calibration The hydrogen and oxidant flow sensors installed in the Dual Plasma Controller have very good repeatability, but significant non-linearity. They have each been factory calibrated at the midrange flow rate (50 SCCM) using an NIST traceable flow meter. Over the typical operating range for the SCD, the flow sensors should produce accuracy of better than ±10% of reading. However, due to sensor non-linearity at low or high flow extremes, error greater than this could be observed.
Detector Sensitivity Detector sensitivity is an indicator reflecting the performance characteristics of a given system, and is a useful tool to determine when Detector maintenance is warranted. Sensitivity is typically reported as a minimum detection limit (MDL) as calculated from the following formula: MDL 0.
Assembling the Dual Plasma Burner for Component Replacement with the SCD The following procedure can be used to assemble the Dual Plasma Burner for use with the SCD or for replacement of Burner components, such as ceramic tubes. Refer to Figure 1 on page 26 for proper part nomenclature. 1 Slide the 0.066" internal diameter (I.D.) double taper ferrule onto the lower Burner tube. The tube should extend approximately 2 mm past the end of the ferrule.
Figure 26 Proper Ferrule Orientation to the Large Ceramic Tube Figure 27 Large Ceramic Tube Properly Inserted into the Quartz Heater Assembly 7 Position the upper ceramic tube into the long axis of the splitter fitting so that about 4 mm of it extends past the top of the fitting. Slide the 0.054" ID double tapered ferrule over the upper ceramic tube.
Figure 28 Orientation of the Double Taper Ferrule Figure 29 Positioning the Upper Tube in the Union Fitting 8 Approximately 1.5 cm of the large ceramic tube should extend above the top of the quartz heater assembly. Slide a 1/4" Swagelok nut over the large ceramic tube and then also slide a 1/4" ferrule over the tube (flat side on back of the nut).
adapter, rotate this fitting so that the brazed H2 line is aligned 180 ° (opposite) from the oxidizer Inlet port. Figure 30 Tightening the Heater Swivel Nut 12 Making sure that the Burner inlet fitting does not loosen, use a 1/2" wrench on a flat of the tapered union fitting and 9/16" wrench on the 1/4" Swagelok nut of the Burner adapter to tighten the tapered union fitting 1/4" past finger-tight.
15 Carefully bend the H2 line into position so that the 1/16" Valco nut and ferrule can be screwed into the side port of the splitter fitting. Tighten the connection of the H2 line to the splitter fitting using a 3/8" wrench on the vertical flat of the splitter fitting and 1/4" wrench on the Valco nut. 16 Make sure that no other connections have loosened or moved out of alignment, if so, reposition or retighten the fittings as needed. 17 The assembled Burner is now ready for re-installation on the GC.
Assembling the Dual Plasma Burner for Component Replacement with the NCD The following procedure can be used to assemble the Dual Plasma Burner for use with the NCD or for replacement of Burner components, such as ceramic tubes. Refer to Figure 2 on page 27 for proper part nomenclature. Note that the lower section of the NCD Burner is identical to the lower section of the SCD Burner.
Figure 33 Proper Ferrule Orientation to the Large Quartz Tube Figure 34 The Quartz Tube Properly Inserted into the Quartz Heater Assembly 8 Insert the lower burner tube into the center of the quartz tube and finger tighten the heater swivel nut onto the tapered union fitting, then tighten an additional 1/4 turn making sure not to break the quartz tube. 9 To begin the final tightening, use a 7/16" wrench and 5/16" wrench to tighten the 1/4" Burner adapter one-quarter turn past finger-tight.
10 Using a 5/8" wrench on the heater swivel nut and a 1/2" wrench on one of the flats of the tapered union fitting, tighten the heater swivel nut one-quarter turn past finger-tight. Using a 5/16" wrench on the ¼" Burner adapter, rotate this fitting so that the brazed H2 line is aligned 180 ° (opposite) from the oxidizer Inlet port.
Tube Replacement for the SCD The Burner has two combustion tubes that require replacement: the upper ceramic tube and the Large Ceramic Tube. Generally the tubes should be replaced only if sensitivity decreases. The “Troubleshooting” chapter provides additional information to assist in determining whether tube replacement may be necessary. Refer to Figure 1 on page 26 for proper part nomenclature. Follow the instructions below for tube replacement.
Figure 38 Positioning the Upper Tube in the Union Fitting 10 Holding the splitter fitting, gently insert the upper ceramic tube into the large ceramic tube coaxially, to avoid placing stress on the fragile upper ceramic tube. Lower the splitter fitting into place to engage the threads of the 1/4" Swagelok nut. Tighten finger-tight. 11 If you do not need to replace the Large Ceramic Tube, proceed to step 19. 12 Remove the Tapered Union Fitting from the bottom of the Burner.
Figure 40 Large Ceramic Tube Properly Inserted into the Quartz Heater Assembly 15 Approximately 1.5 cm of the large ceramic tube should extend above the top of the quartz heater assembly. Slide a 1/4" Swagelok nut over the large ceramic tube and then also slide a 1/4" ferrule over the tube (flat side on back of the nut). 16 To begin the final alignment and tightening, use a 7/16" wrench and 5/16" wrench to tighten the 1/4" Burner adapter one-quarter turn past finger-tight.
nut of the Burner adapter to tighten the tapered union fitting one-quarter turn past finger-tight. 19 Rotate the quartz heater assembly so that the thermocouple and heater leads are in the same plane and pointed in the same direction as the peg on the Burner inlet fitting. Turn the splitter fitting so that H2 inlet port is also aligned with the peg on the Burner inlet fitting.
Tube Replacement for the NCD The Burner has one quartz combustion tube that requires replacement. Generally the tube should be replaced only if sensitivity decreases. The “Troubleshooting” chapter provides additional information to assist in determining whether tube replacement may be necessary. Refer to Figure 2 on page 46 for proper part nomenclature. Follow the instructions below for tube replacement. 1 Turn off power to the GC and the Controller and let the system cool down under vacuum.
Figure 44 Large Quartz Tube Properly Inserted into the Quartz Heater Assembly 10 Insert the lower burner tube into the center of the quartz tube and finger tighten the heater swivel nut onto the tapered union fitting, then tighten an additional 1/4 turn making sure not to break the quartz tube. 11 To begin the final tightening, use a 7/16" wrench and 5/16" wrench to tighten the 1/4" Burner adapter one-quarter turn past finger-tight.
Figure 45 NCD Tube Replacement Detail Figure 46 NCD Tube Replacement Detail 15 The assembled Burner is now ready for re-installation on the GC, including column placement.
Agilent 355 Sulfur and 255 Nitrogen Chemiluminescence Detectors Operation and Maintenance Manual 7 Troubleshooting Solving Detector Problems 106 Power Problems 107 Ozone Generation Problems 109 Response Problems 111 Temperature Reading Problems 112 Diagnosing General Problems 113 Agilent Technologies 105
Solving Detector Problems A basic understanding of the Detector helps one systematically diagnose and solve Detector problems. Many symptoms may be caused by more than one problem and these are the most difficult to troubleshoot. It should be pointed out, however, that analysis of sulfur or nitrogen compounds has traditionally been very difficult because of the inherent reactivity and instability of the compounds themselves.
Power Problems The first step in the determination of a power related problem is to verify power to the pump, Controller, and Detector itself. The inability to establish power may be as trivial as a blown fuse. Fuse requirements and positions on the Detector are indicated in see Figure 47 and Table 4. Repeated fuse failure is an indication of a more serious situation.
3 Remove the old fuses from the holder and replace with new fuses. If the Controller still does not power on after replacing the fuse, contact Agilent. Consult Table 4 for the appropriate replacement fuse.
Ozone Generation Problems Following the verification of power to the instrumental components, the next step in tracing a problem is the determination of ozone production. With the ozone toggle off and the vacuum pump on, read the signal output on the front of the Detector. Toggle the ozone on. A properly operating Detector will typically display a difference in background of 0.2 to 2 mV.
Plugged Restrictor Lines Plugged restrictor lines are verified by turning off the air/oxygen regulator located inside the door of the Detector and observing little or no change in the pressure as indicated on the regulator. The plug can be located in either the pre-ozone restrictor or the post-ozone restrictor (see Figure 3). A partially plugged restrictor line can result in a non-linear signal, or reduced sensitivity which will vary with the flow of ozone. Replace the restrictor lines.
Response Problems Low or no response problems are the most difficult to troubleshoot on the Agilent SCD and NCD as they may arise from one source or a combination of sources. Primarily, response problems are due to combustion problems, and Burner integrity should be investigated first. It is beyond the scope of this supplement to deal with all possible chromatography related problems.
Temperature Reading Problems Normally, the controller displays the burner temperature set-point. For diagnostic purposes, a switch in the controller (JP2) can be positioned to allow the display of the actual thermocouple temperature reading. When the actual temperature and set-point temperature agree, the heater indicator light on the front of the controller is illuminated. Note that there is a slight offset between these readings.
Diagnosing General Problems Table 5 Troubleshooting Detector Issues Problem Possible Cause Diagnosis No Response No ozone Continue below. See No Little or no difference in output signal between ozone Ozone in Problem column. ON vs. OFF. Typically the background signal will be 0.3-0.8 mV higher with the ozone ON. No Ozone Blown fuse Ozone indicator light remains off when ozone button is pushed. Replace ozone fuse. No Ozone High Voltage Transformer and/or ozone generator is inoperative.
Table 5 Troubleshooting Detector Issues (continued) Problem Possible Cause Diagnosis Corrective Action Low Response Contaminated ceramic tubes. If there does not appear to be a leak, then the tubes should be inspected. Contamination can result from column bleed, samples which may contain volatile metal complexes, and large injections of coke forming hydrocarbons. Replace tubes. Wandering Baseline Poor temperature control. Monitor the temperature on the Controller.
Table 5 Troubleshooting Detector Issues (continued) Problem Possible Cause Diagnosis Corrective Action Burner Fault Cycles. (off and ON) Cracked tube. Pressure increases >525 torr, Burner faults. Cycle repeated as temperature and pressure reset. Replace broken tubes. Burner Fault Cycles (off and ON) Leak in Burner. Pressure increases >600 torr, Burner faults. Cycle repeated as temperature and pressure reset. Locate and repair leaks, check integrity of ferrules.
Table 7 Troubleshooting Burner Issues Problem Possible Cause Diagnosis Corrective Action Fuses Blow on Startup Shorted heater element. Inspect for exposed wires or broken insulation around wire leads. Measure resistance leads, should not be 0. Take Burner top off and reseat insulation around heater leads. Low Sensitivity Leaks at ferrules or fittings. For SCD, use a microliter syringe containing a small amount of sulfur compound e.g., CS2 to “snoop” for leaks while watching mV output.
Index C Calibration of Flow Sensor, 88 Ceramic Tube Replacement, 98 Column Insertion Distance, 61 D Detection Limits, 76 Detector cleaning, 83 display output controls, 65 initial check, 69 operating conditions, 75 operation, 73 power controls, 64 schematic, NCD, 36 schematic, NCD (nitrosamine mode), 37 schematic, SCD, 35 shut down, 77 signal controls, 65 start-up procedure, 72 Dry Piston Pump installation, 52 Dual Plasma Burner assembling for NCD, 95 assembling for SCD, 90 cross-section illustration for NC
Operation and Maintenance Manual
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