Hi everyone,
Can somebody advice me on what could be possible cause of retention time shift and unstable areas (meaning poor repeatability) in GCMS? I have included picture below where day1 and day2 means that standards were run in different days. Is that a normal behaviour? Our system is INTUVO GCMS thus we are not cutting our columns or anything like that because we are using guard chips instead.
The GC method is attached as text file
INSTRUMENT CONTROL PARAMETERS: GCMS -------------------------------------- Fri May 27 14:00:29 2022 Control Information ------- ----------- Sample Inlet : GC Injection Source : GC ALS Injection Location: Front Mass Spectrometer : Enabled No Sample Prep method has been assigned to this method. GC GC Summary Run Time 16 min Post Run Time 0 min Cycle Time Optimization Fast Cool (default) Oven Temperature Setpoint On (Initial) 70 °C Hold Time 7 min Post Run 70 °C Program #1 Rate 20 °C/min #1 Value 150 °C #1 Hold Time 5 min Equilibration Time 0.25 min Max Temperature 240 °C Maximum Temperature Override Disabled Slow Fan Disabled ALS Injector Syringe Size 10 μL Injection Volume 0.2 μL Solvent A Washes (PreInj) 3 Solvent A Washes (PostInj) 3 Solvent A Volume 4 μL Solvent B Washes (PreInj) 3 Solvent B Washes (PostInj) 3 Solvent B Volume 4 μL Sample Washes 3 Sample Wash Volume 4 μL Sample Pumps 6 Dwell Time (PreInj) 0 min Dwell Time (PostInj) 0 min Solvent Wash Draw Speed 300 μL/min Solvent Wash Dispense Speed 6000 μL/min Sample Wash Draw Speed 300 μL/min Sample Wash Dispense Speed 6000 μL/min Injection Dispense Speed 6000 μL/min Viscosity Delay 0 sec Sample Depth Disabled Injection Type Standard L1 Airgap 0.2 μL Solvent Wash Mode A, B Sample Overlap Mode Sample overlap is not enabled ALS Errors Pause for user interaction SS Inlet He Mode Split Heater On 250 °C Pressure On 2.0699 psi Total Flow On 57 mL/min Septum Purge Flow On 6 mL/min Pre-Run Flow Test On Pre-Run Flow Test Action on Failure Abort Gas Saver Off Split Ratio 50 :1 Split Flow 50 mL/min Liner A Liner has not been selected. Column Column #1 Flow Setpoint On (Initial) 1 mL/min Post Run 0.57353 mL/min Column Information Agilent 123-9334UI-INT: US20400239 DB-BAC1 UI Temperature Range 20 °C—270 °C (270 °C) Dimensions 30 m x 320 μm x 1.8 μm Column lock Locked In SS Inlet He Out MSD (Initial) 70 °C Pressure 2.0699 psi Flow 1 mL/min Average Velocity 30.691 cm/sec Holdup Time 1.6291 min Control Mode Constant Flow Column Outlet Pressure 0 psi Agilent Intuvo 9000 GC Components Guard Chip Temperature Setpoint On (Initial) 210 °C Post Run 100 °C Model Number G4587-60565: Intuvo SSI Guard Chip Track Oven Off Max Temperature 450 °C Isothermal Setpoints Bus Temperature On 200 °C Use Default Bus Temperature On Valve 1 Type Gas Sampling Valve GSV Loop Volume 1 mL Load Time 0.5 min Inject Time 0.5 min Signals Signal #1: Test Plot Description Test Plot Save Off Data Rate 50 Hz Signal #2: Description None Signal #3: Description None Signal #4: Description None MS Information -- ----------- General Information ------- ----------- Acquisition Mode : SIM Solvent Delay (minutes) : 4.5 Tune file : D:\MassHunter\GCMS\1\5977\ATUNE.U EM Setting mode Gain : 5.000000 Number of SIM Groups : 2 Run Time (if MS only) : 650 minutes [SIM Parameters] Group 1 Group ID : toluen Resolution : 0 Group Start Time : 4.5 Number of Ions : 2 Ions Dwell In Group :( Mass, Dwell) ( Mass, Dwell) ( Mass, Dwell) ( 91.00,50 ) ( 92.00,50 ) Group 2 Group ID : amyl alcohol Resolution : 0 Group Start Time : 5.8 Number of Ions : 2 Ions Dwell In Group :( Mass, Dwell) ( Mass, Dwell) ( Mass, Dwell) ( 55.00,50 ) ( 70.00,50 ) [MSZones] MS Source : 230 C maximum 250 C MS Quad : 150 C maximum 200 C Timed Events ----- ------ Number Events= 0 END OF MS ACQUISITION PARAMETERS TUNE PARAMETERS for SN: US1422L218 --------------------------------- Trace Ion Detection is OFF. 34.593 : EMISSION 70.007 : ENERGY 31.712 : REPELLER 90.331 : IONFOCUS 17.627 : ENTRANCE_LENS 1121.040 : EMVOLTS 1388 : Actual EMV 5.00 : GAIN FACTOR 358.000 : AMUGAIN 123.938 : AMUOFFSET 1.000 : FILAMENT 0.000 : DCPOLARITY 15.482 : ENTLENSOFFSET 0.000 : Ion_Body 0.000 : EXTLENS -1040.000 : MASSGAIN -35.000 : MASSOFFSET END OF TUNE PARAMETERS ---------------------- END OF INSTRUMENT CONTROL PARAMETERS ------------------------------------
Best Regards,
Standwi