products designed to solve nagging gc problems - agilent · ensure the proper and consistent length...

Products Designed to Solve Nagging GC Problems

Abby Folk Chromatography Technical Specialist

Contaminated Gas Fouls the Whole GC

Dirty Lines, Inlet, Column, Detector

More Frequent Maintenance

More Down Time

Replacements Cost Money

Solution = Use only Clean Gas!

Gas Clean Filters – The Insurance Policy

Gas-Clean Filters Design

Sensitive indicators for moistureand oxygen

Note where indicators change

Color! Top or Bottom

Short filter equilibration time

Fast, leak-free filter replacement

• without turning off the gas • NO tools needed

Oxygen Damages GC columns

Repair of the GC column is impossible

Replacements means re-calibration

Replacement means delay

Replacement column costs money

Damage to electron multiplier, filaments

Solution = No Leaks!

Leak Detector G3388B Overview

Key Features

The full list of features is included below:

• Detects thermal conductivity differences

• Audible and visual alerts

• Minimum detection limit – 0.0005 mL/min hydrogen and helium

• Lightweight – only 105 g

• Small – roughly 50 (W) × 19.5(D) × 111(H) mm

• Rechargeable lithium ion battery with over 5 hours of life

• Includes a USB cable for battery charging

• One year warranty from Agilent

How do you make better GC column connections? 1. Start with the right tools and supplies

• Column nuts • Material : stainless – but need brass for MS interface • Choice of right ferrules

2. Proper assembly process

• Make a good clean column cut – every time

• After ferrule is installed

• Fused silica tubing cutters : ceramic, diamond tipped etc.

• Magnifier to inspect the cut - cracked fused silica and flaps of polyimide are active sites that ruin chromatography.

3. Ensure the proper and consistent length of column into the fitting

8

polyimide

Supply Selection: Which Capillary Ferrules to use?

Composition Re-use Max T Use Limitation

Polyimide (Vespel) yes 280 Easy seal Shrink after heating causing leaks after thermal cycle; isothermal only

Graphite yes 450 FID, NPD Inlets Contamination, permeable to air – not for oxygen sensitive detectors

Polyimide/graphite (85% / 15%)

limited 350 MS, ECD, Inlets Still shrink after thermal cycles creating leaks; need to retighten regularly

Flexible metal no 450 Capillary Flow Technology (backflush, splitters,…)

May not seal well with damaged fittings or rough surfaces

9

polyimide/graphite graphite

“Long” ferrules for MS transfer lines and MS interface nut

“Short” ferrules for inlet and detector configurations on Agilent GC’s

flexible metal

Ensure the proper length … Column Installation Tools Follow the manufacturer’s recommended procedure • Optimized GC performance and reproducibility requires ensuring the proper length of column into the fittings, every time • Column Installation pre-swaging tools for the

Split/Splitless, Multi Mode and Purge Packed Inlets available for Agilent GC models 7890/7820 and 6890/6850, for graphite or metal ferrules

G1099-20030 MS Install Tool

G3440-80217 Graphite Ferrules Metal Ferrules G3440-80218

10

Graphite Ferrules Have a Down Side Too!

Pros • High temperature range (450C) • Low Cost • Soft, easily conforms Con • Can flake, fall apart or extrude • Permeable NOT recommended with MS or ECD

Active sites in the flow path

Extensive inlet maintenance needed

Supply Selection: Graphite/polyimide blend ferrules Graphite / polyimide (vespel) blend ferrules are very popular

• Recommend • Long style for Mass Spec • Short for Inlets, and other oxygen sensitive detectors, like ECD

• Soft enough to make seal against rough surfaces

• Fairly high temperature stability (350C)

• Don’t extrude beyond the fitting when tightened (like graphite)

• Lower air permeability than pure graphite

12

Flexi-Metal Ferrules: Touchless Dial Packaging

o Easy column insertion o No lost ferrules o No contamination risks

13

Capillary column nuts

Column nuts are determined by the instrument fitting

Basic mechanical fittings with little enhancements

• Brass for the MS

• Some finger tight designs for ease of use

New design addresses ease of use and productivity issues of leaking and over tightening

14

What if you … Could install the column easily

Finger tighten, without tools that cause over tightening

And make leak free connections

Which don’t need to be retightened

Every time?

Self-Tightening Column Nuts

Video at agilent.com/chem/STnutvideo

• Reliable performance: Innovative spring-driven piston continuously presses against ferrule – maintaining a leak-free seal • Less wasted time: No retightening needed after repeated thermal cycles • Ease of use: Finger-tight, consistent connections without tools • Faster maintenance: Low-torque seal prevents sticking or crumbling during removal • Leak Free = Lower column bleed: Longer column life

Self Tightening Column Nuts

For mass spec transfer line p/n 5190-5233

For inlet or detector p/n 5190-6194

Short ferrule exposes more thread of the fitting for better sealing also no need for a short and long ferrule

Self-Tightening Column Nuts

The BIGGEST Problem in GC is…

There are more things that DON’T go through a GC than DO!

….therefore, don’t inject anything and you’ll never have problems.

OK, inject, but realize that everything just got dirty…deal with it!

Where Does it Get Dirty?

Here

Here

Here

Here

Here

Here

What Are You Doing!?

It’s in the Inlet! Do Inlet Maintenance

- Trim the Column

- Replace the Liner

- Replace the Gold Seal

- Replace the Syringe

- Replace the Split Vent Trap, Split Vent Line

- Rinse the Inlet

Do not aggressively scrub the inlet !!

Start as clean and inert as possible

Bonus Peaks – Where do they come from?

CONTAMINATION in INJECTOR or FLOW (carrier gas)

-Contaminated consumables

-Carryover from a backflash or previous sample

-Bad tank of gas or traps have expired

-Septum bleed

*TIP = Run a blank run…it should be blank!

Bonus Peaks - Ferrule Contamination

5 10 15 20 25

pA

18

20

22

24

26

28

Agilent

Vespel/Graphite Ferrule from a bag

Agilent coated O-Ring ougases

15

17

19

21

23

25

27

0 5 10 15 20 25 30 35 40 45

min

pA

Agilent’s Non-Stick O-ring

Competitor R

ALLTech O-Ring outgases

14

16

18

20

22

24

26

28

0 5 10 15 20 25 30 35 40 45

min

pA

Head Space Analysis Vial equilibrium time: 60 minutes Vial equilibrium temperature: 150°C

Competitor A

Bonus Peaks - O-Ring Contamination

“Off-Brand” O-Ring Issues Controlled Substances Analysis, H2 Carrier

Residue on top of inlet weldment

Problem Resolution: Agilent Non-Stick Liner O-Ring p/n 5188-5365, 10PK

Peak Tailing – What causes this?

1. ACTIVITY either in inlet or column

-Reversible adsorption of active compounds

(-OH, -NH, -SH)

2. FLOW PATH PROBLEM - dead volume, obstruction, poor installation, or severe column contamination

Miscellaneous – temperature issues for late eluters, overloading of PLOT columns, co-elution, polarity mismatch between phase, solute or solvent, and some compounds always tail

*Tip = Inject a light hydrocarbon, should not tail unless flow path problem.

Symptom – Tailing of Active Compounds 1. n-Nitrosodimethylamine 2. Aniline 3. 1,4-Dichlorobenzene-d4 4. Benzoic Acid 5. Naphthalene-d8 6. Acenaphthene-d10 7. 2,4-Dinitrophenol 8. 4-Nitrophenol 9. 2-Me-4,6-dinitrophenol 10. 4-Aminobiphenyl 11. Pentachlorophenol 12. Phenanthrene-d10 13. Benzidine 14. Chrysene-d12 15. 3,3’-Dichlorobenzidine 16. Benzo[b]fluoranthene 17. Benzo[k]fluoranthene 18. Perylene-d12

Sample: 0.5 ng on column loading with ISTD Column: 20m 0.18mm 0.18µm Carrier: Helium 37cm/sec, Ramped flow; 0.7ml/min (0.1min) to 1.3ml/min (15ml/min2) Oven: 35oC (2.5 min) to 80oC (40oC/min), 15oC/min to 200oC, 8oC/min to 275oC (2 min) Injection: 0.5µl, Splitless, 280oC, purge flow 30ml/min at 0.75 min MSD: Transfer Line 290oC, Source 300oC, Quad 180oC

2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 0

50000

100000

Time (min)

Abundance

1

2

3 5 6

7 8

10

11

9

12

13

14

15

16

17

18

4

2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 0

50000

100000

Time (min)

Abundance

1

2

3 5 6

7 8

10

11

9

12

13

14

15

16

17

18

4

Solution – Ultra Inert GC Column 1. n-Nitrosodimethylamine 2. Aniline 3. 1,4-Dichlorobenzene-d4 4. Benzoic Acid 5. Naphthalene-d8 6. Acenaphthene-d10 7. 2,4-Dinitrophenol 8. 4-Nitrophenol 9. 2-Me-4,6-dinitrophenol 10. 4-Aminobiphenyl 11. Pentachlorophenol 12. Phenanthrene-d10 13. Benzidine 14. Chrysene-d12 15. 3,3’-Dichlorobenzidine 16. Benzo[b]fluoranthene 17. Benzo[k]fluoranthene 18. Perylene-d12

Sample: 0.5 ng on column loading with ISTD Column: 20m 0.18mm 0.18µm Carrier: Helium 37cm/sec, Ramped flow; 0.7ml/min (0.1min) to 1.3ml/min (15ml/min2) Oven: 35oC (2.5 min) to 80oC (40oC/min), 15oC/min to 200oC, 8oC/min to 275oC (2 min) Injection: 0.5µl, Splitless, 280oC, purge flow 30ml/min at 0.75 min MSD: Transfer Line 290oC, Source 300oC, Quad 180oC

2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00

0

50000

100000

Time (min)

Abundance

1

2

3

4

5

6

7 8

9

10

11

12

13

14

15

16

17

18

2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00

0

50000

100000

Time (min)

Abundance

1

2

3

4

5

6

7 8

9

10

11

12

13

14

15

16

17

18

AND Ultra Inert Liners

Touchless packaging Easy installation of new, clean liner

without risk of contamination from touching

Includes non-stick plasma treated O-ring

More and More “Touchless” Packaging

Agilent UI Gold Seal: Deactivated Gold Surface

• Soft gold plating is essential for proper sealing

• Ultra Inert chemistry blocks active sites (gold is NOT inert)

• Smooth surface doesn't leak

Agilent MIM seal Competitor’s machined seal

Reliable ppb and ppt measurements require

attention to the little things!

New Product: Agilent Inert Inlet

UltiMetal Plus treatment creates inert surface 7890 inlet weldment & shell • Limits adsorption/degradation of active analytes • Optimum for Trace GC/MS and GC-ECD pesticide analyses

Agilent’s proven

proprietary Ultimetal Plus surface

treatment

Putting It All Together – Inert Flow Path vs. Standard Flow Path

20.20 20.40 20.60 20.80 21.00 21.20 21.40 21.60

10000

20000

26000

Green = Inert Flow Path Blue = Standard Flow Path

Column: Agilent J&W HP-5ms UI 30 m x 0.25 mm x 0.25 um Oven: 100°C 4 min hold, 10°/min to 280°C, 6 °/min to 300°C (4.67 min hold), Carrier : Helium 52.7 cm/s (2 mL/min) set at 100°C, EPC-Constant Flow Inlet: Pulsed Splitless 35 PSI pulse until 0.73 min, 0.75 min purge 50 ml/min, gas saver 20, ml/min at 2 min Inlet liner: Ultra Inert with wool / Standard single taper liner with wool (p/n 5190-3165) Gold Seal: UI Gold Seal / Standard gold seal Detector: MSD Scan mode 40 t0 450 m/z, 230 °C source temp, 150 °C Quad temp, 310 °C transfer line

1

2 3

4

5

1. Dronabinol 2. Oxycodone 3. Temazepam 4. Flunitrazepam 5. Diacetyl morphine

Drugs of Abuse 250 ppb using HP-5ms UI

Broad Peaks – Why?

INJECTOR -Poor Installation -Change in injection solvent -Change in settings (temps/flows) -Poor sample focusing -Large change in sample concentration -Breakdown or adsorption FLOW -Change in gas velocity -Constant Flow vs Constant Pressure COLUMN -Contamination -Damaged/old stationary phase -Breakdown or adsorption -Reverse Solvent Effect

Splitless Injection Reverse Solvent Effect

DB-1, 15 m x 0.25 mm I.D., 0.25 µm 50°C for 1 min, 50-210°C at 20°/min; Helium at 30 cm/sec 1. 1,3-DCP 2. 3-hexanol 3. butyl acetate 4. 1-heptanol 5. 3-octanone 6. 1,2-dichlorobenzene

0 1 2 3 4 5 6 Time (min.)

1 2 3 4 5 6 Time (min.)

Hexane Methanol

1

2 3

4

5 6

1

2

3

4

5 6

Retention Gap Also Called A Guard Column

Usually 2-10 meters long and same diameter as the column (or larger if needed)

Injector Detector

Deactivated Fused Silica Tubing

Union Column

Fixing the Reverse Solvent Effect 3 m x 0.25 mm I.D. Retention Gap

DB-1, 15 m x 0.25 mm I.D., 0.25 µm 50°C for 1 min, 50-210°C at 20°/min; Helium at 30 cm/sec 1. 1,3-DCP 2. 3-hexanol 3. butyl acetate 4. 1-heptanol 5. 3-octanone 6. 1,2-dichlorobenzene

0 1 2 3 4 5 6 Time (min.)

Hexane

1 2 3 4 5 6 Time (min.)

Methanol 1

2 3

4

5 6

1

2

3

4

5 6

Agilent Ultra Inert Press Fit

Press Fit Connectors

Inertness, seal and transparency are key parameters

Competitor Press-Tight

Maximum Force Required to “pull apart”

0.0

0.5

1.0

1.5

2.0

2.5

1 2 3 4

Poun

ds (f

orce

)

Pull Value, 0.25 mm I.D. Columns

Ultra Inert Quartz Fused Silica Glass Press Fit Connector Type

Strong bond between FS polyimide & press fit UI deactivation layer

Press Fit Connector

5190-6979 Ultra Inert Universal Press Fit Union for 0.10 to 0.75mm, 10/pk 5190-6980 Ultra Inert Universal Press Fit Y-Splitter

Blood Alcohol Application: Agilent Solution

7890 GC

S/S Inlet

FID CH2

FID CH1

Un-Purged Splitter

0.4 m x 0.45 mm Retention Gap

Column 1: DB-ALC1

Column 2: DB-ALC2

7697A Headspace Sampler

HSS Transfer

Line

42

Better Connections: Capillary Flow Technology Devices

UltiMetal Plus Ultimate Union/UltiMetal Plus Tee • Stainless Steel Micro Fluidic plates technology • Deactivation essential to block active sites • Column connection easy to assemble Release hole for

stuck ferrules

Using Flexible Metal ferrules to overcome issues • UltiMetal Plus surface chemistry prevents activity • Flexible design reduces risk of over tightening or column

breaks • Leak free seal remains after repeated temperature cycles

43

Flexi-Metal Ferrules: Touchless Dial Packaging

o Easy column insertion o No lost ferrules o No contamination risks

44

Current Ferrule Stiff, prone to

cause damage to column or fitting

Small ID

compression (40 to 60um) – leaks

Tolerances poorly controlled

Agilent Flexi-Metal Ferrule Computer aided Design Finite Element Analysis More flexible

Less column damage

Large range of

ID compression (100 to 120um) – less leaks issues

Compare current vs new Agilent ferrule

Impact of ferrule surface on inertness

46

4 x10

0

1

2

4 x10

0

1

2

Counts vs. Acquisition Time (min) 4.5 5 5.5 6 6.5 7 7.5

Untreated FMF Post column Std 500ppb

FMF + UltiMetal Plus Post column Std 500ppb

Acephate Omethoate

Demeton-S

Acephate Omethoate

Demeton-S

Very small amount of ferrule surface exposed to active pesticides

Conclusions for a Problem Free GC

Start With Ultra Inert/High Quality Consumables

Never Have a Leak (no oxygen)

Use Gas Clean Filters

Never Inject Anything (dirty or reactive)

Don’t Touch Anything

Do Routine Inlet Maintenance Often

TECHNICAL SUPPORT

1-800-227-9770, #3

E-mail: [email protected]

Troubleshooting Resources

Online Video Maintenance Manual http://www.chem.agilent.com/en-US/support/installation/gcms/Pages/default.aspx

Troubleshooting Guide Publication –G3170-90037.pdf

http://www.chem.agilent.com/en-US/support/installation/gcms/Pages/default.aspx

NOW IT’S EASIER THAN EVER TO GET RELIABLE GC RESULTS THROUGH BETTER GC

CONNECTIONS FROM AGILENT

www.agilent.com/chem/betterGCconnections

Order the poster… View the video…

50

http://www.agilent.com/chem/betterGCconnections

products designed to solve nagging gc problems - agilent · ensure the proper and consistent length...

Documents