1. Micro-GC channel with µ-TCD
Hardware CP-4900 DMD
µ-DMD
µ-DMD fully integrated into CP-4900 Micro-GC hardware
µ-DMD serial connected, via heated transfer line,(inert) with µ-TCD (modified)
Micro-GC operates under standard conditions
Micro-GC channel with µ-TCD

2. Radio active cell is regarded as a closed source
DMD Channel
The 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 and
UI board
Driftgas
Zero Air or N2

4. Hardware CP-4900 DMD Housing modification
Differences on standard CP-4900:
main board revision/ IOC
MPU firmware V1.30 build 01
Housing modification
CP-4900 module TCD connections
Heated transfer line DMD 4Watt
NO UPGRADE POSSIBLE

5. Highlights of CP-4900 DMD CP-4900 DMD Analyzers Solutions
Turnkey Solution for a specific application field
Fully integrated into the CP-4900 Micro-GC
Using µ-DMD (Micro Differential Mobility Detector)
High sensitivity
< 100 ppb detection limit
Unique selectivity
No interference with sample matrix
Detect components even when they are co-eluting

6. Sensitivity CP-4900 DMD < 100ppb
Sensitivity of CP-4900 DMD
Sensitivity CP-4900 DMD < 100ppb 1 2 3 4 5 6 7
Hexane vapor as sample matrix.
µ-DMD signal
1. Iso-propyl mercaptan
2. Tert-butyl mercaptan
3. Sec-butyl mercaptan
4. N-propyl mercaptan
5. Iso-butyl mercaptan
6. N-butyl mercaptan
7. Tert-amyl mercaptan
+/- 100ppb each!
µ-TCD signal

7. Selectivity of CP-4900 DMD Selectivity CP-4900 DMD
No interference with sample matrix
Methyl- and Ethyl Acrylate in a natural gas
1. Methylacrylate, 1.8 ppm
2. Ehtylacrylate, 2.5 ppm 1 2
C6-hydrocarbons
µ-DMD signal
µ-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 coupling
µ-DMD serial connected, via heated transfer line,with µ-TCD

10. Principle of operation µ-DMD
Ionization
Component from µ-TCD are ionized
Tunable ion filter
Selective transmission of Components of interest, others are neutralized and hence not detected, they will pass through filter
Detection
Both positive and negative species are detected

11. Principle of operation µ-DMD
The micro-Differential Mobility Detector (µ-DMD) is a tunable ion filter
Detector Selectivity is gained by:
Degree of ionization
Filter per component
Mobility of the ion
Vc or compensation voltage, RF- voltage
Detection
Positive and negative ions
Detector selectivity is additional to chromatographic selectivity

12. Principle of operation µ-DMD
1. Ionization step
Ionization Source: Ni63
The 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 gas
Ionisation Source: Ni63
The 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 filter
Degree of ionization
Mobility of the ion
Voltage on electrode
The 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 ions
At 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 Spectroscopy
Tunable ion filter, which selects the the ion species allowed to pass through the filter
The filtering mechanism is governed by the interaction between the ion and the net applied field that alternates between the high and low electric field strength
Ions which do not pass through the filter are neutralised
Both positive and negative ions are detected

17. Summary CP-4900 DMD Markets

18. Trouble shooting on DMD
Driftgas flow incorrect
Noise problems on DMD
Noise problems on CP-4900
Sensitivity problems
Communication problems
Flow controller
check valve
check for leakage
DMD channel
Interconnection board
check driftgas pressure
Check quality driftgas
Adsorption of the component
RS232 cable
Expert Lite

19. DMD Channel transfer line
Noise testing
Cap the DMD off or remove the complete channel

20. DMD channel Each components 11 ppm 10m Porabound Q
H2S:2015
COS:2683
CH3SH:2212
Each components 11 ppm
DMD Channel:
H2S:222486
COS:206760
CH3SH:366515

21. Loss of sensitivity What to check??? 1) Type and quality driftgas
2) Quality of the calibration mix
3) Tuning DMD

22. Heated transfer line

23. CP-4900 heated transfer line
Take care when installing the heated transfer line over the TCD capillary

24. Expert Lite V2.0
Adjust Vc default
after tuning
Only adjust
step size

25. IAR Generated Binar (*.a43) Upgrade for Sensor board
Boot loader software
IAR Generated Binar (*.a43)
Upgrade for Sensor board
Motorola S record(*.s)
Upgrade for UI board

26. Boot loader software

27. Info on Sionex software
Boot loader software
1) Upgrade software on User Interface board (UI board)
2) Upgrade software on Sensor board
1) Expert Lite info on UI and Sensor firmware