Slide 1: Don't Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention
Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Mark Sinnott Online Application Engineer Alexander Ucci Online Application Engineer October 10, 2019 1 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 2: Exclusive Offer for Attending Agilent Chemistries Webinars
Exclusive Offer for Attending Agilent Chemistries Webinars Receive a 25% discount off any Agilent J&W GC Columns, Agilent LC Columns, Sample Prep Products, Chemical Standards and your most often used GC and LC supplies* • Discount applies on future purchase of up to $3,000 (USD) • Offer good 30 days
Slide 3: Examples of Poor Peak Shape
Examples of Poor Peak Shape Run 1 Run 2 Erratic baseline Symmetrical Overloaded Tailing Elevated baseline Change in peak symmetry Baseline problems Change in peak size Ghost peaks 2 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 4: What Isn't a "Peak"?
What Isn’t a “Peak”? Baseline noise/erratic baseline Mild Contaminated gas, incorrect detector settings, electronics malfunction Severe Spiking PLOT columns shedding, electronic/detector issues 4 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restri
Slide 5: Bad Gas Stinks
Bad Gas Stinks • Use ultrahigh purity carrier gas (99.9995% or greater) • Use the appropriate gas traps • Oxygen in carrier gas is detrimental to GC, resulting in: – Reduced response – Elevated background – Irreversible column damage – Premature filament failure – Excessive source maintenance • Agil
Slide 6: Where Can These Ghost Peaks Come From?
Where Can These Ghost Peaks Come From? Vial contamination Dirty syringe Wash vial contamination Column contamination Inlet contamination 6 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 7: Where Can These Ghost Peaks Come From?
Where Can These Ghost Peaks Come From? Autosampler Vial contamination Dirty syringe Wash vial contamination Column contamination Inlet contamination 7 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 8: Ghost Peaks from Your Syringe
Ghost Peaks from Your Syringe Carryover Possible causes • Insufficient number or type of needle washes • Solvent wash vial empty • Syringe worn or dirty • Sample/solvent mismatch • Dirty autosampler needle guide Suggested actions • Increase number or type of washes • Rinse with a variety of solvents
Slide 9: Washes and Pumps
Washes and Pumps Solvents • Frequently clean or replace wash vials • Traces of previous samples will accumulate over time • Do not refill or “top-off” the vial, instead empty, rinse, and replace solvent • Use a cotton swab to remove particulates from the glass surface Contaminated wash vial bottom C
Slide 10: Washes and Pumps: Diffusion caps
Washes and Pumps “Diffusion caps” • Diffusion caps are very important • Reduce volatile solvent diffusion • Good alternative to using septa, which could core, contaminate wash solvent vial, resulting in septum bleed peaks 4 mL wash vials with fill markings and caps, 25/pk (p/n 5182-0551) Diffusion i
Slide 11: Anatomy of a GC ALS Syringe
Anatomy of a GC ALS Syringe Barrel Flange Needle Termination Plunger Standard plungers PTFE-tipped (shown) • Fit tightly within syringe barrel • Limit sample deposit adsorption • Limit loss of volatile sample • Forms gas-tight seal • Individually fitted to the syringe • Replaceable • Not replaceable
Slide 12: Repeat Injections from the Same Vial
Repeat Injections from the Same Vial Tapered 26 23 Needle Termination 12 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 13: Septum Maintenance: TIC of an Inlet Septum
Septum Maintenance: TIC of an Inlet Septum Common ions for Septa contamination in wash vials or inlet liners can be diagnosed by looking for siloxane siloxane polymers in your total ion chromatogram. Each peak in the chromatogram corresponds to a molecules cyclized (ring structure) siloxane molecule
Slide 14: Deconvoluted Inlet Septa Spectrum
Deconvoluted Inlet Septa Spectrum 10 12 14 16 18 20 Decamethyl Dodecamethyl Tetradecamethyl Hexadecamethyl Octadecamethyl Eicosamethyl cyclopentasiloxane cyclohexasiloxane cycloheptasiloxane cyclooctasiloxane cyclononasiloxane cyclodecasiloxane 14 October 10, 2019 Don’t Fear the Ghost or Unexpected
Slide 15: Where Can These Ghost Peaks Come From?
Where Can These Ghost Peaks Come From? Inlet contamination Vial contamination Dirty syringe Wash vial contamination Dirty detector Column contamination Inlet contamination 15 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 16: Inlet
Inlet Septa • Injection efficiency: – Main function of the inlet is to produce a narrow sample band at the head of the column – One of the most important aspects to any high Liner resolution GC method • Must be reproducible • The liner volume must be large enough to accommodate the solvent’s phase t
Slide 17: Backflash
Backflash Cause • Vaporized sample expands 100 to 1000 times • Portions may leave the liner • Occurs when vapor volume > liner volume Potential problems: • Loss of sample • Baseline interferences • “Ghost” peaks • Tailing solvent front or major component 17 October 10, 2019 Don’t Fear the Ghost or U
Slide 18: Typical Solvent Expansion Volumes
Typical Solvent Expansion Volumes Solvent Vapor volume (µL) of 1 µL Liquid Water 1010 Methanol 450 Carbon disulfide 300 Methylene chloride 285 Acetone 245 n-Hexane 140 18 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 19: Backflash: Minimizing
Backflash Minimizing • Large volume liner (possibly tapered) • Small injection volume • Low expansion solvent • Low injector temperature • High carrier gas flow rates • High head pressures (possibly pulsed) – Smaller column diameters • Usually start with 0.5 µL or less Use vapor volume calculator ht
Slide 20: Contamination from Your Hands
Contamination from Your Hands Column: Agilent J&W DB-5ms, 30 m x 0.25 mm, 0.25 µm Carrier: H2, 60 cm/s, constant flow Injector: split 1:20, 250 ℃ Detector: FID, 320 ℃, N2 makeup gas Oven: 40 ℃ for 0.75 min, 40–325 ℃ at 20 ℃/min, 325 ℃ for 30 min Red: liquid soap Blue: system blank Procedure: (1) One
Slide 21: More and More "Touchless" Packaging
More and More “Touchless” Packaging 21 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 22: Septa
Septa • Typical cost of one premium septum (list), $1.25. • Typical cost of one GC column, 30 m x 0.25 mm id, $450. • Proactively change inlet septa. • Agilent packing eliminates contamination of septa. • “Centerguide septa” puts less train on syringe compared to solid septa. • Do not overtighten se
Slide 23: Septum Maintenance: Septum Coring
Septum Maintenance: Septum Coring • Pieces of rubber from the septum may break off and fall into inlet liner after many injections • This is called septa coring • Replace the inlet septa and liner frequently to prevent septa contamination • Use a cone tipped syringe to reduce the chance of tearing t
Slide 24: Split/Splitless Inlet
Split/Splitless Inlet The split vent trap What is it? Where is it? On a 7890 GC 24 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 25: What Your Split Vent Trap Should Not Look Like
What Your Split Vent Trap Should Not Look Like 25 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 26: Split/Splitless Inlet
Split/Splitless Inlet Split vent trap changed Before split vent trap maintenance After split vent trap maintenance 26 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 27: Cleaning the Split Vent Trap Lines
Cleaning the Split Vent Trap Lines Inspect the liner O-ring sealing surface. It must not have any nicks, cuts, leftover O-ring, or stuck on sample residue. Clean with swabs and solvent. Inspect the split vent hole. It must not be blocked. This hole is hard to see. You can remove the copper split lin
Slide 28: Cleaning the Split Vent Trap Lines
Cleaning the Split Vent Trap Lines But the best way to verify that the split vent line is clear is to backflush solvent from the entrance to the split vent trap back into the inlet. Cool off inlet and oven. Wear safety glasses. 1. Remove liner and column. 2. Place a beaker in the oven underneath the
Slide 29: When Do I Change Each Part?
When Do I Change Each Part? Item Typical Schedule Comments Septum nut can get warn and shed metal particles Septum nut 3-6 months into the liner. Replace to minimize activity in the inlet/liner. Check movement of plunger and replace if it does not Syringe Every 3 months move freely and cannot be cle
Slide 30: Split/Splitless Cleaning
Split/Splitless Cleaning If the body needs cleaning, use a plastic burette brush and solvent in a cold inlet. Scrubbing the inlet with a metal brush is not recommended. Most applications do not need the inside of the metal to be cleaned harshly. 30 October 10, 2019 Don’t Fear the Ghost or Unexpected
Slide 31: How Did It Become Contaminated in the First Place?
How Did It Become Contaminated in the First Place? 31 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 32: The Matrix
The Matrix If your target ions are buried beneath matrix peaks, it might be time to trim the column or do sample cleanup 500 ppb ethenoprox 1.7 + EIC(93.1) Scan Extract_00003.D in black tea 1.6 1.5 1.4 1.3 1.2 7.210 1.1 1 0.9 0.8 0.7 0.6 x10 1 +EIC(93.1) Scan Extract_00003.D 0.5 4.2 0.4 4 3.8 0.3 3.
Slide 33: Agilent Bond Elut Sample Cleanup Products
Agilent Bond Elut Sample Cleanup Products Filtration cartridges and plates Solid Phase Extraction cartridges and plates Synthetic Chem Elut S Captiva EMR Lipid 33 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 34: Liquid/Liquid Extraction (LLE)
Liquid/Liquid Extraction (LLE) • LLE has been successfully used as a method of sample preparation for many years. • It separates the more organic solvent-soluble compounds from the more water-soluble compounds using water immiscible organic solvents. • It can remove many interfering substances, such
Slide 35: Drawbacks of Liquid/Liquid Extraction
Drawbacks of Liquid/Liquid Extraction • LLE does have drawbacks – Inconsistent results from one analyst to another • Shaking time • Shaking motion • Determination of where to cut between layers – Emulsions – Labor intensive – Quite Tedious with small sample sizes (<5 mL) – Challenging with large num
Slide 36: How Does SLE Work?
How Does SLE Work? Add Add aqueous solvent sample Hold 5 min Load Gravity elute 1. Add aqueous sample to SLE sorbent 2. Wait 5 minutes 3. Elute with water immiscible solvent 36 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 37: What Is SLE Sorbent?
What Is SLE Sorbent? • There are two types of SLE media – Diatomaceous earth (DE) based products like our Chem Elut brand of SLE products • A mined fossil diatom material, which is heterogeneous and inconsistent from one mine to the next × Naturally occurring; mined Diatomaceous earth × Broad partic
Slide 38: Chem Elut S – 15 minute Hold Time
Application note 5994-0951EN Chem Elut S – 15 minute Hold Time Large scale format comparison with aromatic amines Recovery (30 µg/mL; n = 3), 87-119% Chem Elut S 5 mL Chem Elut S 10 mL Chem Elut S 20 mL 120.0 100.0 80.0 60.0 40.0 20.0 0.0 10.0 9.0 Reproducibility (30 µg/mL; n = 3), RSD 0.4-8.2% 8.0
Slide 39: Enhanced Matrix Removal: Agilent Captiva EMR-Lipid
Enhanced Matrix Removal: Agilent Captiva EMR-Lipid EMR-Lipid sorbent technology effectively traps lipids through two mechanisms: • Size exclusion – unbranched hydrocarbon chains (lipids) enter the sorbent; bulky analytes do not • Sorbent chemistry – lipid chains that enter the sorbent EMR are trappe
Slide 40: Application Case – Pesticides in Edible Oil by GC/MS/MS
Application Case – Pesticides in Edible Oil by GC/MS/MS Classification Classification Pesticides Pesticides Classification Pesticides Dichlorvos Lindane Dichlorfluanid Sulphamide Trichlorfon Aldrin Tolylfluanid Sulfotep Endrin Captan Organochlorine Endosulfan Diazinon Phthalimide Folpet Chlorpyripho
Slide 41: Pesticides in Edible Oil by GC/MS/MS
Pesticides in Edible Oil by GC/MS/MS Sample preparation procedure visual Olive oil Olive oil extract Captiva Transfer Mix w/ 20% EMR-Lipid LLE x2 water cleanup supernatant Olive oil Supernatant for extract MgSO4 salt GC/MS/MS EMR-Lipid analysis partition eluent 41 October 10, 2019 Don’t Fear the Gho
Slide 42: Captiva EMR-Lipid Cleanup Improves Analytes S/N Ratio and Integration Accuracy
Captiva EMR-Lipid Cleanup Improves Analytes S/N Ratio and Integration Accuracy on GC/MS(/MS) Pesticide Captan Permethrin Deltamethrin EMR-Lipid cleanup Zirconia sorbent cleanup + MRM (151.0 -> 79.1) Post-S 50ppb Fatty dSPE C1-3.D Counts x10 5 1.4 1.2 1 C18/PSA 0.8 0.6 cleanup 0.4 0.2 *13.174 min. 0
Slide 43: EU Priority PAH Analysis in Pumpkin Seed Oil Using Bond Elut EMR-Lipid
EU Priority PAH Analysis in Pumpkin Seed Oil Using Bond Elut EMR- Lipid Cleanup by GC/MS/MS Application note 5994-0593EN 43 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 44: The Importance of Sample Cleanup
The Importance of Sample Cleanup Beef liver – Untreated Beef liver – EMR-Lipid treated 50 samples with cleanup For sample cleanup help, please contact us at spp-support@agilent.com 50 samples without cleanup 44 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention
Slide 45: The Benefits of Glass Wool in Your Liner
The Benefits of Glass Wool in Your Liner What is glass wool used for? • Prevents nonvolatile matrix from entering Filtration column • Provides volatilization surface for liquid Vaporization injections, promotes mixing with carrier gas Needle • Increases reproducibility by wiping needle wiping after
Slide 46: What's New? Glass Wool Alternative Liners
What’s New? Glass Wool Alternative Liners Ultra Inert liners with sintered glass frits • Designed for dedicated Low frit splitless analyses single taper • Ideal for SVOCs and OC/OP liner pesticides • General purpose split/splitless Mid frit liner single • Ideal for basic drugs analysis taper liner P
Slide 47: Where Can These Ghost Peaks Come From?
Where Can These Ghost Peaks Come From? Column contamination Vial contamination Dirty syringe Wash vial contamination Column contamination Inlet contamination 47 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 48: Does Your Baseline Look Like This? Do You See Extra Peaks?
Does Your Baseline Look Like This? Do You See Extra Peaks? When it should look like: 48 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 49: Example of Column Contamination
Example of Column Contamination 2.21 1.5e4 1.4e4 Agilent J&W DB-624 QC test mix after 75 injections of oily sample 1.3e4 3.30 1.2e4 1.1e4 1.0e4 6.03 9000 9.26 8000 10.46 7000 14.40 17.86 6000 0 5 10 15 20 Time (min.) *Temperature program// 35°C hold 1.50 min // 30°/min to 65°C, hold 10 min 49 Octobe
Slide 50: Example of Column Contamination
Example of Column Contamination 1 1/2 meters removed* 1.3e4 QC test mix to upper temperature limit 1.2e4 1.1e4 We have more 1.0e4 semivolatile 9000 contamination 8000 7000 6000 5000 0 10 20 30 40 50 60 70 Time (min.) *Before column bake Temperature program // 35 °C, hold 1.50 min // 30 °C/min to 65
Slide 51: Example of Column Contamination
Example of Column Contamination 1.2e4 2.80 1.1e4 1.0e4 7.34 9000 10.79 8000 17.19 12.33 7000 20.56 6000 5000 0 5 10 Time (min.) 15 20 25 *Before column rinse and bake Temperature program // 35 °C hold 1.50 min // 30° C/min to 65 °C, hold 10 min 51 October 10, 2019 Don’t Fear the Ghost or Unexpected
Slide 52: Carryover Ghost Peaks
Carryover Ghost Peaks Osthole Meranzin Isomeranzin x10 2 1.05 1 1 Final temp 250 °C 0.95 0.9 0.85 0.8 0.75 Initial injection 0.7 0.65 0.6 0.55 0.5 Repeat injection 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 -0.05 -0.1 x10 2 1.05 1 Final temp 280 °C 1 0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 Carryove
Slide 53: Another New Column: J&W DB-HeavyWAX
Another New Column: J&W DB-HeavyWAX The WAX column you’ve been waiting for • Increased temperature range – 280 °C isothermal – 290 °C programmed • Increased thermal stability – Stable retention times – Consistent peak order • Lower bleed – Greater sensitivity for “heavier” compounds – Increase analy
Slide 54: Where Can These Ghost Peaks Come From?
Where Can These Ghost Peaks Come From? Other Sources Vial contamination Dirty syringe Wash vial contamination Column contamination Inlet contamination 54 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 55: Inlet Breakdown
Inlet Breakdown • Thermally labile compounds • Very “active” compounds • Derivatize compounds • Inert flow path helps 55 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 56: Breakdown of DDT
Breakdown of DDT Pentachlorophenol DDT Benzidiene DDD DFTPP DDE DDM 14.5 14.6 14.7 14.8 14.9 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 17 17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8 17.9 18 18.1 18.2 18.3 18.4 18.5 18.6 18.7 18.8 18.9 19 19.1 19.2 19
Slide 57: Agilent Inert Flow Solution
Agilent Inert Flow Solution Agilent Ultimetal Plus inlet weldment, shell and transfer lines Agilent Ultimetal Plus– TCD, FPD, NPD/FID jets Agilent Ultra Inert inlet liner Agilent Ultimetal Plus ferrules Agilent Ultimetal capillary flow technology Agilent J&W Ultra Inert GC column devices, Ultimate u
Slide 58: Additional Troubleshooting Techniques
Additional Troubleshooting Techniques 58 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 59: Perform a Noninjection "Blank"
Perform a Noninjection “Blank” Remove syringe from autosampler If you see peaks, you have some sort of inlet Run your program contamination likely 59 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 60: Condensation Test
Condensation Test Procedure Blank 1 Blank 2 Remove syringe Leave GC at 40–50 ℃ from autosampler for >8 hours Run two blank runs and compare the two 60 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 61: Condensation Test
Condensation Test Results First blank run is worse • Contaminants (from injector, lines, traps or carrier gas) carried into the column Blank runs the same • Contaminants are not strongly focused on the front of the column 61 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting
Slide 62: Jumper Tube Test
Jumper Tube Test Purpose Analytical column • Helps to locate the source of contamination or noise Sample • Isolates GC components Autosampler Power Syringe Gases Vacuum system Inlet Detector Detector Quadrupole Source MS Interface GC electronics electronics October 10, 2019
Slide 63: Jumper Tube Test
Jumper Tube Test Isolate the detector • Remove column from the detector Sample • Cap detector and turn on Autosampler Power • Blank run Syringe Gases Vacuum system Inlet Detector Detector Quadrupole Source MS Interface GC electronics electronics 63 October 10, 2019 Don’t Fear the Ghost or Unexpected
Slide 64: Jumper Tube Test
Jumper Tube Test Isolation of Detector Results Detector OK Detector is the problem 64 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 65: Jumper Tube Test
Jumper Tube Test Isolate the injector • Connect the injector and detector Sample – 1 to 2 m deactivated fused silica tubing Autosampler • Turn on carrier gas Power Syringe Gases • Blank run Vacuum system Inlet Detector Detector Quadrupole Source MS Interface GC electronics electronics 65 October 10,
Slide 66: Jumper Tube Test
Jumper Tube Test Isolate the Injector Results Injector OK Injector, lines, or carrier gas contaminated 66 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 67: Jumper Tube Test
Jumper Tube Test Isolate the column Analytical column • Re-install the column Sample • Set up as before Autosampler Power Syringe Gases • Blank run Vacuum system Inlet Detector Detector Quadrupole Source MS Interface GC electronics electronics 67 October 10, 2019 Don’t Fear the Ghost or Unexpected P
Slide 68: Jumper Tube Test
Jumper Tube Test Isolate the column - results • Problem returns: It’s the column • Problem gone: Previous leak, solid debris, or installation problem 68 October 10, 2019 Don’t Fear the Ghost or Unexpected Peaks: Troubleshooting and Prevention Agilent Restricted
Slide 69: Conclusion
Conclusion • Distinguish between a “peak” and “nonpeak” • Isolate different components to hunt down the ghost peaks (autosampler, inlet, column, and so on) • Perform sample cleanup when necessary • Proactively change consumables • Please reach out to us for any assistance you might need 69 October 1
Slide 70: Contact Agilent Chemistries and Supplies Technical Support
Contact Agilent Chemistries and Supplies Technical Support 1-800-227-9770 option 3, option 3: Option 1 for GC and GC/MS columns and supplies Option 2 for LC and LC/MS columns and supplies Option 3 for sample preparation, filtration, and QuEChERS Option 4 for spectroscopy supplies Option 5 for chemic