How To Achieve Lowest Carry-Over - Agilent Technologies Agilent 1260 Infinity System User's Manual

How to Achieve Lowest Carry-over

Carryover is measured when residual peaks from a previous
active- containing injection appear in a subsequent blank solvent injection.
There will be carryover between active injections which may lead to
erroneous results. The level of carryover is reported as the area of the
peak in the blank solution that is expressed as a percentage of the area in
the previous active injection. The Agilent 1260 Infinity Autosampler is
optimized for lowest carryover by careful design of the flow path and use
of materials in which sample adsorption is minimized. A carryover figure
of 0.002 % should be achievable even when a triple quadrupole mass
spectrometer is the detector. Operating settings of the autosampler allow
the user to set appropriate parameters to minimize carryover in any
application involving compounds liable to stick in the system.
The following functions of the autosampler can be used to minimize
carryover:
• Internal needle wash
• External needle wash
• Needle seat backflush
• Injection valve cleaning
The flow path, including the inside of the needle, is continuously flushed
in normal operation, providing good elimination of carryover for most
situations. Automated delay volume reduction (ADVR) will reduce the
delay volume but will also reduce the flushing of the autosampler and
should not be used with analytes where carryover might be a problem.
To ensure lowest carry- over, consider the following recommendations:
• Always use the autosampler with the injection valve in mainpass
• Flush the exterior of the needle with an appropriate solvent using the
• If possible, reduce the draw speed to 10 µL/min.
• Use Agilent capped 2 mL vials (Screw cap vial, 2 mL (5182- 0556)).
• If the seat is contaminated, use an appropriate seat- flush procedure.
• Use flushing solvents that are capable of dissolving the sample
• Use acidic mobile phases for basic compounds.
1260 Infinity Binary LC - System User Guide
position.
flush port. The flush time should be a minimum of 10 s.
compounds.
Optimization of the Agilent 1260 Infinity Binary LC

How to Achieve Lowest Carry-over

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