1.1.1 Flow-through-needle injector
The sample manager's flow-through-needle mechanism aspirates a sample and holds
it in the sample needle, prepared to inject the sample onto the column. The needle
serves as part of the injection flow path when the sample is pushed onto the column.
The flow-through-needle mechanism facilitates the transfer of HPLC methods,
improves injection accuracy and decreases cycle time for small-volume injections,
and does not require learning new injection modes. Mobile-phase gradients pass
through the needle during injection, ensuring complete sample recovery.
1.1.2 Wash solvent
The wash system uses a single solvent to clean the outside of the sample needle and
prime the wash system. The solvent does not enter the injection flow path.
1.1.3 Purge solvent
The primary function of the purge solvent is to move sample along the injection
pathway. The purge solvent also primes the sample syringe and injection pathway.
The solvent’s injection onto the column occurs only during auto-dilution, when it is
used as the dilution solvent.
1.1.4 Software enhancements
1.1.4.1 Quantum Synchronization
Introducing a low-pressure sample into the high-pressure fluid stream during
injection causes a pressure pulse that can affect chromatographic results. The
Quantum Synchronization feature reduces the affect of this pressure pulse. The
sample manager and solvent manager communicate to automatically coordinate the
injection sequence, enabling the solvent manager to provide additional pressure at
the exact moment the sample manager switches its injector valve to the inject
position, to introduce the low-pressure sample.
1.1.4.2 Gradient Smart Start
Before each sample injection, a sample manager typically performs wash sequences
and aspirates the appropriate sample volume. When these tasks are completed, the
solvent manager begins to deliver the gradient to the injection valve. The dwell
volume of the system affects the amount of time required for this gradient to reach
the column and can be a significant component of the overall cycle time.
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