Agilent Technologies, Inc. · NYSE:A
Agilent Technologies — Technical Presentation (November 2016)
63 slides from Agilent Technologies's technical presentation, Nov 15, 2016
Slide 1: Practical Steps in GC Troubleshooting
Practical Steps in GC Troubleshooting Techniques, Tips, and Tricks Simon Jones Application Engineer GC Columns & Supplies Page 1
Slide 2: What went wrong and how to fix it…
What went wrong and how to fix it… Common problems Troubleshooting tools Troubleshooting examples Page 2
Slide 3: Everything was just fine and then this happened! How do I troubleshoot?
“Everything was just fine and then this happened! How do I go about TROUBLESHOOTING?” Page 3
Slide 4: Everything was just fine and then this happened!
“Everything was just fine and then this happened!” Logic = Something changed (slowly or sudden) = Something is different Track Events – log book -Changed column, liner, septum, syringe, etc. -Injected samples, other method, etc. -Did maintenance, cut column, inlet flush, etc. Page 4
Slide 5: Logical Troubleshooting
Logical Troubleshooting Troubleshooting Starts with Isolating the problem •There are 5 basic areas from where the problem arises •INJECTOR •FLOW •COLUMN •DETECTOR •ELECTRONICS • But of course it can always be some COMBINATION Knowing what can & can’t cause the symptom is the key Page 5
Slide 6: Typical Problems of Optimized Methods Becoming Unoptimized
Typical Problems of Optimized Methods becoming Unoptimized…and the Reason Why. • Peak Tailing – Flow Path or Activity • Bonus Peaks – In Sample or Back Flash (Carry Over) • Split Peaks – Injector Problems, Mixed Solvent • No Peaks – Wasn’t Introduced, Wasn’t Detected • Response Changes – Activity, I
Slide 7: Peak Tailing
Peak Tailing INJECTOR or COLUMN is Active -Reversible adsorption of active compounds (-OH, -NH, -SH) FLOW problem - dead volume, obstruction, poor installation, or severe column contamination Miscellaneous - overloading of PLOT columns, co-elution, polarity mismatch between phase, solute or solvent,
Slide 8: Bonus Peaks
Bonus Peaks Column: DB-5 30 m x 0.53 mm I.D., 1.5 µm J&W P/N: 125-5032 Oven: 60°C for 1 min 60-300°C at 20°/min Wh = 0.106 300°C for 3 min Carrier Gas: Helium at 36 cm/sec Injector: Split 1:100, 250°C sample C7 - C20 Detector: FID, 250°C Wh = 0.029 Wh = 0.030 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00
Slide 9: Bonus Peaks or Ghost Peaks
Bonus Peaks or Ghost Peaks Contamination in INJECTOR, COLUMN or FLOW (carrier gas) -Carry-over 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! Page 9
Slide 10: Bonus 'Siloxane' Peaks
Bonus ‘Siloxane’ Peaks Page 10
Slide 11: GC Column Bleed Ions
GC Column Bleed lons ee a ee ee ee aS Agilent Technologies
Slide 12: Column Bleed is Influenced by
Column Bleed is Influenced by: 1.3e4 1.2e4 Phase type Temperature 1.1e4 Column 1.0e4 dimensions 9000 DB-624 30M x .53mm I.D., 3.0µm 24 pA / 260°C 8000 7000 DB-1 30m x .32mm I.D., .25µm 12 pA / 320°C 6000 0 5 10 15 20 25 Time (min.)
Slide 13: Split Peaks
Split Peaks INJECTOR (poor sample introduction) -Injecting the sample twice (some how?) VOLATILITY -Mixed sample solvent (polarity difference) High boilers dropping out on Cold Spots -Sample in syringe needle (manual inject) -Transfer line temps INJECTOR (activity) -Unions or fittings not -Breakdown
Slide 14: No Peaks
No Peaks DETECTOR (not on or not operational) INJECTOR (not working) -Plugged syringe/plunger not moving -Wrong injector (or detector) -Huge leak (older systems) -No carrier gas flow NOT the COLUMN Unless… -Broken column or No column Page 14
Slide 15: Peak Response - All Change in Size
Peak Response All Change in Size INJECTOR -Leaky syringe -Split ratio set incorrectly -Wrong purge activation time -Septum purge flow too high -Injector temperature too low* DETECTOR (response problem) -Settings or flows changed -Electronics failing *Tip = Ask is it all of them or some of them, if a
Slide 16: Peak Response - Some Change in Size
Peak Response Some Change in Size INJECTOR or COLUMN is active/contaminated -Irreversible adsorption of active compounds (-OH, -NH, -SH) -Decomposition of sample -Temperature Change – Discrimination -Evaporation from sample *Tip = If only some change, then ask which ones? If active compounds then ac
Slide 17: Peak Fronting
Peak Fronting Shark Fin Shaped or Just Slight COLUMN (contaminated) -Overload (More pronounced with large solute and phase polarity differences) INJECTOR -Column installation -Compound very soluble in injection solvent (need retention gap) -Mixed sample solvent OTHER -Co-elution -Breakdown Page 17
Slide 18: Retention Time Shift
1.75 Retention Time Shift INJECTOR 4.50 -Leak in the septum 2.00 -Change in injection solvent 3.00 -Large change in sample 4.75 concentration FLOW 2.75 3.25 -Change in gas velocity COLUMN 5.50 -Contamination -Damaged stationary phase 4.00 -Loss of stationary phase -Change in temperature Page 18
Slide 19: Effect of Sample Overload on Retention Time and Peak Shape
Effect of Sample Overload on Retention Time and Peak Shape 1400 ng 7 ng 8 9 10 11 min Page 19
Slide 20: Loss of Resolution
Loss of Resolution Separation Peak Width Resolution is a function of separation and peak width Page 20
Slide 21: Loss of Resolution - Separation Decrease
Loss of Resolution - Separation Decrease Separation COLUMN -Different column temperature -Contamination (more phase?) -Matrix components co-eluting Peak Width -Different column phase? Page 21
Slide 22: Loss of Resolution - Peak Broadening
Loss of Resolution - Peak Broadening FLOW Separation -Change in carrier gas velocity -Make-up gas COLUMN -Contamination Peak Width -Phase degradation INJECTOR (efficiency) -Settings, Liner, Installation, etc. Page 22
Slide 23: Baseline Disturbances
Baseline Disturbances Sudden Changes, Wandering, or Drifting WANDER COLUMN or DETECTOR -Not fully conditioned or stabilized (electronics) -Contamination FLOW -Changes in carrier and/or detector gas flows -Valves switching, leaks DRIFT Page 23
Slide 24: Noisy Baseline
Noisy Baseline MILD SEVERE FLOW DETECTOR -Contaminated gas -Air leak - ECD, TCD -Incorrect detector settings -Electronics malfunction COLUMN -Bleed if at high temperature -In detector flame (poor installation) Page 24
Slide 25: Spiking Baseline
Spiking Baseline DETECTOR -Particles entering the detector -Random: poor connection -Regular: nearby "cycling" equipment (electronics) Page 25
Slide 26: Quantitation Problems
Quantitation Problems DETECTOR -Poor stability (electronics) or Baseline disturbances (contamination) -Outside detector's linear range or wrong settings Activity (adsorption) in INJECTOR or COLUMN 392538403 OTHER INJECTOR -Co-elution -Technique, settings, conditions -Matrix effects -Syringe worn -Sa
Slide 27: What is NOT caused by a Column???
What is NOT caused by a Column??? Peaks!! Any reproducible, sharp ‘chromatographed’ peak! Siloxanes Degradation product peaks: Endrin Aldehyde, Endrin Ketone, DDE, DDP…. Carryover of sample compounds Splitting of peaks Page 27
Slide 28: Troubleshooting Tools
Troubleshooting “Tools” Bleed Profile: baseline problems Inject a non-retained peak: peak shape problems Test mix: all problems Isolate the components: all problems Condensation Test: baseline problems Jumper Tube Test: baseline problems Page 28
Slide 29: Generating a Bleed Profile
Generating a Bleed Profile 1.3e4 Produce when the column is new (for future reference) 1.2e4 when there is a baseline problem 1.1e4 1.0e4 9000 8000 7000 6000 0 5 10 Time (min.) 15 20 25 *DB-1 30m x .32mm I.D., .25µm Temperature program // 40°C, hold 1 min // 20°/min to 320°C, hold 10 min. Page 29
Slide 30: Non-Retained Peak Shapes
Non-Retained Peak Shapes Used to Check Flowpath Good Installation Improper Installation or Injector Leak Potential problems: Injector or septum leak Too low of a split ratio Liner problem (broken, leaking, misplaced) Column position in injector and detector Page 30
Slide 31: Test Mix
Test Mix Used to determine how “good” the column is or if the problem is related to the chemical properties of the analytes. Test Conditions Inlet: Split (250°C) Detector: FID (320°C) Carrier Gas: Hydrogen Flow: 37.3 cm/sec (1.8 ml/min) Holdup Compound: Methane (0.671-min) Temperature Program: Isoth
Slide 32: Test Mixture Components
Test Mixture Components Compounds Purpose Hydrocarbons Efficiency Retention Alcohols Activity FAME’s, PAH’s Retention Acids Acidic Character Bases Basic Character Page 32
Slide 33: Own Test Mixture
Own Test Mixture • More specific to your application • Selective detectors • Concentrations specific to your application • Use same instrument conditions • Easiest to simply inject a calibration standard • Store for future measure of column performance Page 33 Group/Prese
Slide 34: Isolate the Components
Isolate the Components Simplify the system: - example - Direct injection instead of P&T sample introduction Put in a known good column Move column to a different GC, inlet or detector Page 34
Slide 35: Condensation Test
Condensation Test Used* to isolate the cause of: - Erratic baselines - Ghost peaks or carryover *Use when problems are worse after periods of GC non-use Page 35
Slide 36: Condensation Test
Condensation Test Procedure Leave GC at 40-50°C for > 8 hours Blank run Repeat a blank run immediately after the first blank run is complete Compare the two blank runs Page 36
Slide 37: 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 Page 37
Slide 38: Jumper Tube Test
Jumper Tube Test Purpose Helps to locate the source of contamination or noise Isolates GC components Page 38
Slide 39: Jumper Tube Test
Jumper Tube Test Isolate the Detector Remove column from the detector Cap detector and turn on Blank run Page 39
Slide 40: Jumper Tube Test
Jumper Tube Test Isolation of Detector - Results Detector OK Detector is the problem Page 40
Slide 41: Jumper Tube Test
Jumper Tube Test Isolate the Injector Connect the injector and detector - 1-2 meters deactivated fused silica tubing Turn on carrier gas Blank run Page 41
Slide 42: Jumper Tube Test
Jumper Tube Test Isolate the Injector - Results Injector OK Injector, lines or carrier gas contaminated Page 42
Slide 43: Jumper Tube Test
Jumper Tube Test Isolate the Column Reinstall the column Setup as before Blank Run Page 43
Slide 44: 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 Page 44
Slide 45: And Now Let's do Some Troubleshooting
And Now Let’s do Some TROUBLESHOOTING “3's Agilent Technologies
Slide 46: Troubleshooting-Example #1
Troubleshooting-Example #1 Page 46
Slide 47: A Real Troubleshooting Example
A Real Troubleshooting Example 30 No Peaks 28 26 24 22 20 18 16 14 10 20 30 40 50 Page 47
Slide 48: Logical Steps Taken to Find Peaks
Logical Steps Taken to Find Peaks (most of our problems are leaks and plugs) Is the flame Lit? put glass piece over FID outlet----Answer in this case, Water condenses look at output in instrument guage-- is the digital value greater than 0.0? Answer in this case is approximately 16.2 pico amps I
Slide 49: Peaks !!
Peaks !! 30 28 26 24 22 20 18 16 14 0 10 20 30 40 50 Page 49
Slide 50: Troubleshooting-Example #2
Troubleshooting-Example #2 Page 50
Slide 51: DB-624 Column
DB-624 COLUMN QC Test Mix 2.71 1. 1,2-Dichloropropane Column: DB-624 8.0e4 2. Octane 30m x 53mm I.D., 3.0µm 3. Tetrachloroethylene Carrier: Helium at 40 cm/sec 7.0e4 4. Chlorobenzene measured at 35°C 5. Nonane Injector: Mega Direct, 260°C 6.0e4 Detector: FID, 300°C 7.43 Oven: 35°C for 1.50 min 10.92
Slide 52: Example of Column Contamination
Example of Column Contamination 2.21 1.5e4 1.4e4 DB-624 QC Test Mix* 1.3e4 3.30 After 75 Injections of Oily Sample 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 Page 52
Slide 53: Column and Liner Contamination
Column and Liner Contamination Inlet coil of column Page 53
Slide 54: Example of Column Contamination
Example of Column Contamination 1.2e4 2.80 1.1e4 Removed 1 1/2 m from injector end * 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°/min to 65°C, hold 10 min Page 54
Slide 55: Looks Fixed Doesn't it?
Looks Fixed Doesn't it? Page 55
Slide 56: Example of Column Contamination
Example of Column Contamination 1 1/2 mtrs removed* 1.3e4 QC Test mix to Upper Temperature Limit 1.2e4 1.1e4 1.0e4 9000 8000 7000 6000 5000 0 10 20 30 40 50 60 70 Time (min.) *Before Column rinse and bake. Temperature program // 35°C, hold 1.50 min // 30°/min to 65°C, hold 15 min // 20°/min to 260°,
Slide 57: Backflush Column
Backflush Column Rinse with 10ml each: Methanol, Methylene Chloride, Hexane Capillary column Special connector and ferrule Flexible teflon tubing 1/16" flexible teflon line Special adapter to regulated pressure source Cap Vial Beaker for solvent collection Capillary column Page 57
Slide 58: Jumper Tube Test
Jumper Tube Test Used to Isolate Source of Contamination . Cap off the detector and establish normal gas flows and temperature. . Plot the baseline using a temperature program. If flat...... . Connect 1 meter of deactivated tubing between the injector and detector . Plot the baseline using a tempera
Slide 59: Contaminated Inlet
Contaminated Inlet 1.0e4 Jumper Tube Test* 9000 8000 7000 6000 5000 0 10 20 30 40 Time (min.) *1/2 mtr length of .53 mm I.D. deactivated tubing Temperature program // 35°C, hold 1.50 min // 30°/min to 65°C for 15 min Page 59
Slide 60: Rinsing Injector
Rinsing Injector Carrier gas line GC Oven Injector body MeCl2 C6 Page 60
Slide 61: Troubleshooting Tips
Troubleshooting Tips 1. Isolate the problem. (Blank Run, Inject Un-retained Compound, Jumper Tube Test) 2. Change only one variable at a time. 3. Compare before/after chromatograms. (Peak shape, response, retention, baseline rise, background, look for trends, etc.) 4. Utilize Technical Support. Page
Slide 62: Remember
Remember Complete system = Carrier Gas + Injector + Column + Detector + Data System Multiple cause and effect Do not change too many variables at once Page 62
Slide 63: Technical Support
TECHNICAL SUPPORT 1-800-227-9770, #3, #3, #1 E-mail: gc-column-support@agilent.com Page 63
Agilent Technologies — Technical Presentation (November 2016) on 6ix