6890 gc detectors - the flame ionization detector

Slide #1

6890 GC Detectors - The Flame Ionization Detector

Comparison of GC Detectors

MSD

IRD

PID

FPD (S)

NPD (P)

NPD (N)

ECD

FID

TCD

AED

10 10 10 10 10 grams-15 -12 -9 -6 -3

fg pg ng ug mg

1 ppt 1 ppb 1 ppm 0.1 % 100 %

Sensitivity

(SIM) (SCAN)

ELCD (X)

ELCD (SorN)

Slide #2

6890 GC Detectors - The Flame Ionization Detector - Main Components

Igniter

Teflon Insulator

Collector

Interconnect/Spring

Electrometer

Jet

Heater/Sensor Assembly

Detector Base Assembly

Column Adapter

Slide #3


Slide #4

6890 GC Detectors - The Flame Ionization Detector - Theory of Operation

1. H2 - Air Flame2. Sample is burned in flame

3. When burned produces charged Ions4. Ions attracted to collector

5. Collector current converted to output via Electrometer

Slide #5


FID EPC Flow Manifold

Detector Pneumatic Connection

Gas Connections to GC

FID Flow Measurement Tool

FID JetPlugged FID Jet

Slide #6


Complete Detector Assembly

FID Collector Removal

FID Igniter Replacement

Slide #7

Jet Type Part Number Jet Tip id

Capillary G1531-80560 0.29 mm0.011"

High Temp G1531-80620 0.47mm0.018"

Jet Type Part Number Jet Tip id

Capillary 19244-80560 0.29mm0.011"

Packed 18710-20119 0.47mm0.018"

PackedWide bore 18789-80070 0.030"

High TempCapillary

19244-80620 0.47mm0.018"

Jets for Capillary-Optimized FID

Jets for Adaptable FID

6890 GC Detectors - The Flame Ionization Detector - Jets

Slide #8


EPC Pneumatics

Air In

Make up In

H2 In

FilterFrit Proportional

valvePressuresensor

Restrictors

PressureControl loop

PS

PS

PS

Slide #9


FID EPC Flow Module

Slide #10


6890 EPC ModuleOriginal Design New Detector Mini-fold

Slide #11


CONFIGURE FRONT DETMkup gas type N2 <Lit offset 2.0Electrometer On

FRONT DET MAKEUP GAS Helium <*Nitrogen

FRONT DET (FID)Temp 250 250 <H2 flow 30.0 30.0Air flow 400.0 400.0Mkup (N2) 30.0 30.0Flame OffOutput 0.0

F DET MAKEUP MODE*Const makeup flow Col+makeup=const <

Mode:Col+mkup=constCombined flow 0.0Makeup flow 0.0

Mode: Const makeup <Mkup flow 0.0 Off

Slide #12


FRONT DET (FID)

Temp 250 250 <H2 flow 30.0 30.0Air flow 400.0 400.0

Mkup (N2) 30.0 30.0

Flame Off

Output 0.0

CONFIGURE FRONT DETMkup gas type N2Lit offset 2.0 <Electrometer On

Slide #13


Optimum hydrogen flow rate versus carrier flow rate

20 30 40 50 60

50

(156)

40

(132)

30

(107)

20

(75)

Carrier Flow (N ), ml/min

Hyd

rog

en

Flo

w (

ml/m

in o

r kP

a)

2

Slide #14


Hydrogen Flow Rate vs Pressure

20 100 150 200 250

80

60

40

20

Pressure (kPa)

Hyd

rogen

Flo

w (

ml/m

in)

Air Flow Rate vs Pressure

100 200 300 400 500

800

600

400

200

Pressure (kPa)

Air F

low

(m

l/min

)

Slide #15


Rare Gases NH3 CS2Nitrogen Oxides H2 COS

Silicon Halides CO O2

H2O CO2 N2Perhalogenated compounds

HCOH HCOOH

Compounds with little or no FID response

Slide #16


Typical Problems

Flame out Spiking Low Sensitivity Noise Drift

Slide #17


Flame won't light

Measure Flows Clean/Replace Jet (6850 Jet Test)

Are column and fittings tight ? Is the tank pressure high enough ?

Is the Detector ON ?

Slide #18

6890 GC Detectors - The Flame Ionization Detector Noisy Baseline

Turn off Air/H2

Replace Detector Board/ interconnect/Teflon Insulators

Electronic/Mechanical Problem

Still Noisy

Check:Filters,Traps,GassesClean Jet

Verify Column max

Contamination problem

Yes

No

Slide #19

HP 6890 - Flame Ionization Detector

Planned Maintenance

- Replace Jet (per Customer)- Clean/Replace Collector- Inspect interconnect and spring- Inspect ignitor glo-plug - replace if necessary- Measure H2/Air/Makeup Flows- Turn off H2 and measure FID Leakage Current - < 2pA- Ignite FID - monitor background and noise

<20 pA and stable- Run customer sample or Agilent Checkout per 6890 Service Manual section 600.

6890 gc detectors - the flame ionization detector

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