Slide 1: Simplifying Sample Introduction
Simplifying Sample Introduction Rachael Simon Product Manager, GC Supplies 1 May 10, 2018
Slide 2: Sample Introduction
Sample Introduction A complex process dependent on many variables. Minimal adsorption Some of the keys to a successful injection: Speedy Narrow injection sample band “The Perfect Injection” No Correct column carryover installation No Just enough discrimination (clean) sample 2 May 10, 2018
Slide 3: Anatomy of a GC ALS Syringe
Anatomy of a GC ALS Syringe Barrel Flang e Needle Termination Plunger 3 May 10, 2018
Slide 4: Anatomy of a GC ALS Syringe
Anatomy of a GC ALS Syringe Barrel Flang e Needle Termination Plunger Cone Tip/PS AS (shown) Used in Agilent autosamplers for optimum performance and reliability by reducing septum coring, Bevel Tip/PS 2 General purpose, excellent choice for transferring liquids from ampoules or vials. For manual GC
Slide 5: Anatomy of a GC ALS Syringe
Anatomy of a GC ALS Syringe • Recommended for chlorinated solvents Barrel Flang e Needle Termination Plunger Cone Tip/PS AS (shown) Used in Agilent autosamplers for optimum performance and reliability by reducing septum coring, Bevel Tip/PS 2 General purpose, excellent choice for transferring liquid
Slide 6: Anatomy of a GC ALS Syringe
Anatomy of a GC ALS Syringe • Recommended for chlorinated solvents Barrel Flang e Needle Termination Plunger Standard plungers Cone Tip/PS AS (shown) • Fit tightly within syringe barrel Used in Agilent autosamplers • Limit loss of volatile sample for optimum performance and • Individually fitted to
Slide 7: Syringe Selection Tips
Syringe Selection Tips • 10µL cone-tip, 23/26s tapered needle with PTFE tipped plunger for most SSL and MMI applications • Taper provides strength of larger needle while minimizing puncture size in septum • Ensure proper syringe is configured in software • Gold vs. blue syringes • Use blue when: – A
Slide 8: Syringe Selection Tips: Microvolume Injections and Syringes
Syringe Selection Tips: Microvolume Injections and Syringes • 5µL syringes are ideal for small volume injections BUT: • Typically shorter lifetime (narrow plunger diameter → bends easier) • Do NOT use in solvent saver mode (too much strain on plunger) • Not available with PTFE tip (plunger sensitive
Slide 9: Need help?
Need help? Check out our online syringe selector tool https://www.agilent.com/search/gn/syringe-selector 6 May 10, 2018
Slide 10: ALS Method Parameters
ALS Method Parameters 7 May 10, 2018
Slide 11: Injection Volume
Injection Volume New GC driver Injection volume selection Syringe capacity: • Avoid injection volumes below the lowest 10% of syringe capacity – Injection will work, but may reproducibility may suffer Old GC driver • ALS software automatically limits max injection volume to 50% of Injection volume s
Slide 12: Starting points for injection volume
Starting points for injection volume Goal: Inject as little sample as possible to meet detection limit Split ≤ 1µL • Ensure compatibility between solvent type, volume, and inlet liner – Use vapor volume calculator Splitless ≤ 2µL • Injection volumes for most organic solvents should be within 1 – 2 µ
Slide 13: Sample Backflash
Sample Backflash Carrier gas in Septum purge H H e e Split vent a a t t e e d d Agilent Confidential 10 May 10, 2018
Slide 14: Sample Backflash
Sample Backflash How To Avoid/Minimize o Reduce injection volume o Larger liner volume o Use pressure pulse Carrier gas in Septum purge o Tapered liner o Choose the o UltiMetal Plus Inlet weldment H H e e Split vent Negative Effects a a o Tailing t t e e o Low compound response d d o Complete compou
Slide 15: Chromatographic signs that your injection volume is too high
Chromatographic signs that your injection volume is too high • Overloading • Watch for highly concentrated samples • Don’t inject too much sample 1 µL injection 0.5 µL injection Less injection Column overload volume = = Fronting peaks More Gaussian peaks
Slide 16: ALS Method Parameters
ALS Method Parameters 12 May 10, 2018
Slide 17: Washes and Pumps: Solvents
Washes and Pumps: Solvents • Ideally, 4 max volume (80%) washes reduces carryover to one part in 10,000 Analyte Solubility @ Potential Analyte for Viscosity Carryover Number & Type of Washes Syringe Solvent Barrel Viscosity Wear Wash Volume 13 May 10, 2018
Slide 18: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 14 May 10, 2018
Slide 19: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 ≤ 2 mL # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 • Use wash vial B > 2 mL • Reduce wash volume • Reduce # of injections 14 May 10, 2018
Slide 20: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 ≤ 2 mL # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 • Use wash vial B > 2 mL • Reduce wash volume • Reduce # of injections 14 May 10, 2018
Slide 21: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 ≤ 2 mL # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 • Use wash vial B > 2 mL • Reduce wash volume • Reduce # of injections 22 line sequence 14 May 10, 2018
Slide 22: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 ≤ 2 mL # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 • Use wash vial B > 2 mL • Reduce wash volume • Reduce # of injections 14 May 10, 2018
Slide 23: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 ≤ 2 mL # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 • Use wash vial B > 2 mL • Reduce wash volume • Reduce # of injections A = 6 washes 14 May 10, 2018
Slide 24: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 ≤ 2 mL # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 • Use wash vial B > 2 mL • Reduce wash volume • Reduce # of injections Solvent A A = 6 washes 22 * 6 * 5…
Slide 25: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 ≤ 2 mL # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 • Use wash vial B > 2 mL • Reduce wash volume • Reduce # of injections Solvent A A = 6 washes B = 12…
Slide 26: Washes and Pumps: How much wash solvent are you using?
Washes and Pumps: How much wash solvent are you using? #𝑝𝑟𝑒 + #𝑝𝑜𝑠𝑡 𝑤𝑎𝑠ℎ𝑒𝑠 ≤ 2 mL # 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛𝑠 ∗ ∗ 𝑤𝑎𝑠ℎ 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑤𝑎𝑠ℎ 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 𝑢𝑠𝑒𝑑 𝑖𝑛𝑗𝑒𝑐𝑡𝑖𝑜𝑛 • Use wash vial B > 2 mL • Reduce wash volume • Reduce # of injections Solvent A Solvent B A = 6 washes…
Slide 27: Washes and Pumps: Solvents
Washes and Pumps: Solvents 10 µL 25 µL • High wash application? Try solvent saver • MUST use PTFE-tipped syringe – Fitted syringes lubricate sufficiently, causing premature failure • 10%, 20%, 30%, 40%, and 50% of syringe size (µL) – Wash volume will automatically be configured upon syringe size sel
Slide 28: Washes and Pumps: Solvents
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
Slide 29: Washes and Pumps: Solvents
Washes and Pumps: Solvents • Choose a (or a series of) wash solvent(s) that make(s) sense for the analysis • Is the analyte soluble in the solvent? • If wash solvent ≠ sample solvent, are they miscible? • Do not use acidic or alkaline solvents with syringes • What other solvents are used/analytes de
Slide 30: Washes and Pumps: Solvents
Washes and Pumps: Solvents • Diffusion caps are important. • Reduce volatile solvent diffusion • Better alternative than using vial septa, which could core, contaminate wash solvent vial → septum bleed peaks 5182-0551, 4 mL wash vials with fill markings and caps 25/pk 07673-40180, Diffusion inserts
Slide 31: Use the right vial
Use the right vial • Choose high quality vials and caps • Poorly constructed vial septa → siloxanes → bleed peaks • Low quality vial → leach contaminants into sample • Choose the right cap/septa for your solvent Page 19
Slide 32: Washes and Pumps: Samples
Washes and Pumps: Samples 20 May 10, 2018
Slide 33: Washes and Pumps: Samples
Washes and Pumps: Samples • Sample washes • Primes syringe barrel with sample, discards into waste bottle • Improves reproducibility • Exercise caution if sequence includes reduced volume samples 20 May 10, 2018
Slide 34: Washes and Pumps: Samples
Washes and Pumps: Samples • Sample washes • Primes syringe barrel with sample, discards into waste bottle • Improves reproducibility • Exercise caution if sequence includes reduced volume samples • Sample pumps • Draws sample into syringe, discards into same vial • Eliminates air bubbles → improves
Slide 35: Washes and Pumps: Samples
Washes and Pumps: Samples • Sample washes • Primes syringe barrel with sample, discards into waste bottle • Improves reproducibility • Exercise caution if sequence includes reduced volume samples • Sample pumps • Draws sample into syringe, discards into same vial • Eliminates air bubbles → improves
Slide 36: Advanced Method Parameters
Advanced Method Parameters 21 May 10, 2018
Slide 37: Sample Depth
Sample Depth • Recommend default (3.6 mm from bottom of vial) • Can change to sample from different heights in the vial • So -2 mm setpoint will sample 1.6 mm from vial bottom • Range is (-2 mm to 30 mm) • Example uses: • analyzing samples that contain sediment (although properly filtering the sampl
Slide 38: Plunger Speed and Viscosity Delay
Plunger Speed and Viscosity Delay Dispense Carryover Air bubbles Draw Inject Goal: get sample in liner quickly 23 May 10, 2018
Slide 39: Plunger Speed and Viscosity Delay
Plunger Speed and Viscosity Delay Fast/Variable • Speed setpoints depend on configured syringe size • Fast/Variable • Same parameters to start, but fast is fixed • Best starting point for almost all hot S/SL applications – Slower draw ensures efficient sampling, prevents air bubbles µL/min µL/min µL
Slide 40: Plunger Speed and Viscosity Delay
Plunger Speed and Viscosity Delay • Viscosity Delay • Time (sec) plunger pauses between pump and injection • Allows additional time for viscous samples to flow into syringe during pump • Use for viscous solvents like isooctane • Use for highly volatile solvents dichloromethane (to prevent cavitation
Slide 41: Injection types and Automated Sample Preparation
Injection types and Automated Sample Preparation • Injection Types • Standard • Sandwich injections • Layered injections • Multiple injections • Air gap • 0.2 µL default • Helps retain sample in syringe before injection Interested? Let us know and we can devote a webinar to this topic 26 May 10, 201
Slide 42: Dwell Time
Dwell Time • Types • Pre dwell time – Mins. needle remains in inlet before injection • Post dwell time – Mins. needle remains in inlet after injection • Example uses: – longer dwell time to simulate manual injection process – longer dwell time to warm syringe needle to inject viscous sample • Fast i
Slide 43: 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/GCMS Columns and Supplies • Option 2 for LC/LCMS Columns and Supplies • Option 3 for Sample Preparation, Filtration and QuEChERS • Option 4 for Spectroscopy Supplies • gc-column-support@Ag
Slide 44: Troubleshooting
Troubleshooting 29 May 10, 2018
Slide 45: Troubleshooting: Bent Plunger or Stuck Syringe
Troubleshooting Problem: Bent Plunger or Stuck Syringe Possible Cause(s): • Particles such as dust, salts, metal, leftover sample, or glass can fill the narrow gap between the plunger shaft and the inside wall of the barrel. • Overtightened septum nut compresses septa, causing excessive resistance d
Slide 46: Troubleshooting: Bent needle
Troubleshooting Problem: Bent needle Possible Cause(s): • Improper needle alignment • Narrow gauge needles (26g) bend more easily than larger gauge (23g) needles • Needles tend to bend when inserted into sample vial, not the inlet. This can be caused by septa that are too “rough” • Needles bent duri
Slide 47: Troubleshooting: No peaks
Troubleshooting Problem: No peaks Possible Cause(s): • Syringe plunger malfunction • Plugged needle • Sample level in vial too low • Sample too viscous Suggested Action(s): • Clean or replace syringe • Check sample level, refill or use low-volume vial insert • Split ALS from rest of system by manual
Slide 48: Troubleshooting: Sample carryover
Troubleshooting Problem: Sample carryover Possible Cause(s): • Insufficient number or type of washes • Solvent wash vial empty • Syringe worn or dirty • Sample/solvent mismatch • Dirty ALS needle guide • Dirty septum nut Suggested Action(s): • Increase number or type of washes • Rinse with a variety
Slide 49: Troubleshooting: Poor Reproducibility
Troubleshooting Problem: Poor Reproducibility Possible Cause(s): • Poor plunger seal • Syringe worn or dirty • Glass walls of syringe are scratched Suggested Action(s): • Clean or replace syringe • Rinse and refill solvent wash vial • Do not allow sample to crystallize inside syringe between injecti
Slide 50: Septum maintenance: Septum coring
Septum maintenance: Septum coring • After many injections, pieces of rubber from the septum may break off and fall into the inlet liner. • 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 tea
Slide 51: Septum maintenance: TIC of an inlet septum
Septum maintenance: TIC of an inlet septum Septa contamination in wash vials or inlet liners can be diagnosed by looking for siloxane polymers in your total ion Common ions chromatogram. Each peak in the chromatogram corresponds to a cyclized (ring structure) siloxane molecule. These molecules for s
Slide 52: Sample Introduction: Important Takeaways
Sample Introduction: Important Takeaways • Successful GC injection is a complex process • Start with a PTFE-tipped 10 µL syringe • Handle the syringe carefully • Avoid pumping plunger when “dry” • Don’t let the wash solvent run low/dry/become contaminated • How long is your sequence? • How is your w