Presentation on theme: "Micro-GC channel with µ-TCD"— Presentation transcript:
1 Micro-GC channel with µ-TCD Hardware CP-4900 DMDµ-DMDµ-DMD fully integrated into CP-4900 Micro-GC hardwareµ-DMD serial connected, via heated transfer line,(inert) with µ-TCD (modified)Micro-GC operates under standard conditionsMicro-GC channel with µ-TCD
2 Radio active cell is regarded as a closed source DMD ChannelThe radiation source used in the SVAC is 63Ni. This material is in the form of a 63Ni foil sheet that is placed within the manifold of the SVAC Sensor Cell Assembly.Radio active cell is regarded as a closed source
3 DMD Channel Sensor board Ni63 source Flow controller Check valve Main board andUI boardDriftgasZero Air or N2
4 Hardware CP-4900 DMD Housing modification Differences on standard CP-4900:main board revision/ IOCMPU firmware V1.30 build 01Housing modificationCP-4900 module TCD connectionsHeated transfer line DMD 4WattNO UPGRADE POSSIBLE
5 Highlights of CP-4900 DMD CP-4900 DMD Analyzers Solutions Turnkey Solution for a specific application fieldFully integrated into the CP-4900 Micro-GCUsing µ-DMD (Micro Differential Mobility Detector)High sensitivity< 100 ppb detection limitUnique selectivityNo interference with sample matrixDetect components even when they are co-eluting
7 Selectivity of CP-4900 DMD Selectivity CP-4900 DMD No interference with sample matrixMethyl- and Ethyl Acrylate in a natural gas1. Methylacrylate, 1.8 ppm2. Ehtylacrylate, 2.5 ppm12C6-hydrocarbonsµ-DMD signalµ-TCD signal
8 Principle of operation µ-DMD Micro-Differential Mobility Detector (µ-DMD)CP-4900 DMD, a joint developed by Varian, Inc. and Sionex Corporation, using Sionex's patented microDMXTM technology.
9 Principle of operation µ-DMD µ-DMD couplingµ-DMD serial connected, via heated transfer line,with µ-TCD
10 Principle of operation µ-DMD IonizationComponent from µ-TCD are ionizedTunable ion filterSelective transmission of Components of interest, others are neutralized and hence not detected, they will pass through filterDetectionBoth positive and negative species are detected
11 Principle of operation µ-DMD The micro-Differential Mobility Detector (µ-DMD) is a tunable ion filterDetector Selectivity is gained by:Degree of ionizationFilter per componentMobility of the ionVc or compensation voltage, RF- voltageDetectionPositive and negative ionsDetector selectivity is additional to chromatographic selectivity
12 Principle of operation µ-DMD 1. Ionization stepIonization Source: Ni63The effluent from the capillary column is ionized by supported by the beta-radiation emission of Ni63.Alternative ionization sources are under development: UV, Corona discharge (plasma ionization). One could consider discharge as a promising technique
13 Principle of operation µ-DMD 2. Entry ion filter by using Zero air or Nitrogen as drift gasIonisation Source: Ni63The Differential Mobility Detector (DMD) is a tunable ion filter, which selects the ion species allowed to pass through the filter by adjusting the voltage, applied between the ion filter electrodes (the drift-tube). The filtering mechanism is governed by the interaction between the ion and the net applied field that alternates between high and low electric field strength.The differential mobility detector is capable to isolate specific components or functionality’s out of a complex matrix. Apart from selective, the DMD is very sensitive.
14 Principle of operation µ-DMD 3. Various transmissions in the tunable ion filterDegree of ionizationMobility of the ionVoltage on electrodeThe drift tube is composed of two parallel plates, 500 micron apart fron each other; length is about 2 cm. As the ions move through the ion filter, a R(adio) F(requency) modulated voltage is applied over the plates the result is that the ions make a zig-zag movement between the plates. The ions that hit one of the plates, nett movement upwards or downwards, are neutralized and are swept out of the system. Those ions that have a nett axial movement equal 0 will pass through the plates towards a detector.
15 Principle of operation µ-DMD 4. Detection of positive and negative ionsAt the end of the drift tube, or ion filter the ions move towards the faraday detectors. There is one for positive ions and one for negative ions. Simultaneously two signals are processed. The information content is high compared to the standard gas chromatography detectors like tcd, fid etc.
16 Principle of operation µ-DMD Differential Mobility SpectroscopyTunable ion filter, which selects the the ion species allowed to pass through the filterThe filtering mechanism is governed by the interaction between the ion and the net applied field that alternates between the high and low electric field strengthIons which do not pass through the filter are neutralisedBoth positive and negative ions are detected
18 Trouble shooting on DMD Driftgas flow incorrectNoise problems on DMDNoise problems on CP-4900Sensitivity problemsCommunication problemsFlow controllercheck valvecheck for leakageDMD channelInterconnection boardcheck driftgas pressureCheck quality driftgasAdsorption of the componentRS232 cableExpert Lite
19 DMD Channel transfer line Noise testingCap the DMD off or remove the complete channel