Autosamplers for Purge and Trap The Best Ones

An autosampler automates the loading of laboratory samples into the sample injector of a chromatograph. In combination, the autosampler and the sample injector are referred to as the autosampler injection system - something that separates compounds from the sample so the chromatograph can detect them. There are five main types of autosampler injection systems:

S/SL (split/splitless) injection systems
On-column inlet systems
PTV injector systems
Gas source inlet systems
Purge and trapsystems
With its dynamic ability to trap low level compounds, the purge and trap system is used for samples whose compounds occur at low-ppb (parts per billion) levels. If they choose an autosampler for purge and trap, many laboratories narrow their choices to the Centurion WS Autosampler and the Archon/OI Model 4552 Autosampler. In case you are evaluating these autosamplers, the comparisons below will aid your evaluation.

Centurion WS Autosampler vs. Archon Autosampler

Comparing the Centurion WS to the Archon/OI Model 4552 ought to be done using criteria that determine the overall value of an autosampler to the user. These criteria are:

Analytical superiority
Mechanical robustness
Productivity
Ease of use
Ease of maintenance
Analytical Superiority
The Centurion WS features electronic, three-position delivery, a programmable 1ul-100ul delivery, and does not require priming. These features give it probably the most versatile, reliable, consistent, and economical IS/Surr delivery systems available. By using a fast hot water rinse in a set volume loop that keeps water in the pathway hot, and flushing the minimizer parameter soil needle and transfer line with P&T's Bake gas, it also features excellent carryover reduction.

The Archon/OI Model 4552 features mechanical, two-position delivery, a 1ul delivery, and requires priming. These features make it less versatile, reliable, consistent, and affordable than the Centurion WS. Its slow hot water rinse with a syringe also offers less carryover protection.

Mechanical Robustness
The Centurion WS displays a higher level of mechanical robustness because of the following specs:

A fully supported X-Y-Z arm
Water vial sampling occurring in the tray
A fiber optic vial sensor
Vial sensing during transport only for soil samples
An elevator mechanism that only carries soil
Modular electronic design
A P&T concentrator that manages flow control
Elimination of the syringe mechanism within most autosamplers
In comparison, the specs for the Archon/OI Model 4552 are that it:

Has an arm whose left side is unsupported
Will not sample water vials in the tray
Features a mechanical switch (not just a fiber optic sensor) that must be manipulated during vial transport
Has an elevator that moves both water and soil samples
Contains an all-in-one printed circuit board instead of modular electronic design
Features separate pressure and flow control
Uses a syringe mechanism, that may lead to syringe errors.
Productivity
The Centurian WS achieves high productivity due to its dual concentrator mode for liquid and soil samples, and its generous sample positioning of 100 water samples and 90 soil samples. These features create cost benefits for the GC/MC process and increase unattended autosampler operation. autosampler The Archon/OI Model 4552 lacks a dual concentrator mode and only features positioning for 51 samples.

Ease of Use
Featuring remote control and intuitive OR WINDOWS 7 Software that's displayed on a 15" smart monitor, the Centurion WS is one of the easiest autosamplers to use. On the other hand, the Archon/OI Model 4552 cannot be controlled remotely, and features an interface that is manipulated with a small keypad.

Ease of Maintenance
The Centurion WS possesses three features which make it easy to maintain: an error tracking and sample log, on-board real-time flow diagrams, and complete on-board diagnostic checks. The Archon/OI Model 4552 will not possess these features.

Conclusion
An autosampler for purge and trap is an important investment for independent researchers and laboratories that analyze solids and liquids using the GC/MC process. Although many laboratories use the Archon/OI Model 4552, it generally does not offer the same analytical superiority, mechanical robustness, productivity, ease of use, and ease of maintenance as the Centurion WS. For large laboratories and independent researchers whose funding depends upon research cost and quality, the Centurion WS the very best autosampler for purge and trap.