How to Automate Sample Preparation

Agilent Technologies has taken an important step forward in automating sample preparation with its 7693A Automatic Liquid Sampler.


Problem: The labor-saving benefits of automation have long been recognized and applied in all types of laboratories. For example, autosamplers are a common sight in separations labs since unattended operation of chromatographs has obvious benefits that are intuitively cost effective. The one area that has been most challenging to automate is sample preparation due to the complexity and variety of samples that typically pass through labs.

Solution: Agilent Technologies has taken an important step forward in automating sample preparation with its 7693A Automatic Liquid Sampler (Figure 1). In designing the new autosampler, Agilent realized that many of the common preparation procedures for chromatography samples could be done by incorporating a precision liquid dispenser along with mixing and heating capabilities into the new design. Addition of a second tower option with a large capacity syringe provides the capability to precisely dispense liquids to a sample vial for common operations such as internal standard addition, solvent dilution, and addition of derivitizing agents. An optional bar code reader/stirrer station that heats up to 80oC is sufficient for most dissolution or derivitization procedures while an optional heater/chiller module maintains samples at up to 50oC to keep solutes in solution while in the tray awaiting injection. To accommodate the in-vial chemistry strategy, it was also necessary to provide the capability to sample at any point in the vial to allow the analyst to select the correct phase for injection. As with any complex technology, software automation is necessary in order to reap full benefit. A simple script command language was developed to allow the analyst to set-up and save methods within a matter of minutes (Figure 2).

Agilent 7693A Automatic Liquid Sampler

Sample Preparation Screen for the Agilent 7693A ALS

Lab managers know that any innovative solution must also be vetted against sound business requirements in order to be successful. In developing the business case for this product, the following benefits show that the solution meets financial, safety, quality, and environmental requirements:

  • Productivity: Automated sample preparation can save ½ hour or more of analyst time per shift which translates to ≈ 550 hours labor savings per year (0.5 hrs per shift x 3 shifts per day x 365 days per year).
  • Safety: Automated sample preparation typically reduces personnel exposure time to potentially toxic solvents and reagents by more than 75 percent. Reduced quantities used in small scale preparation also limit exposure and reduce risks associated with other solvent properties such as flammability. Ergonomic issues are also eliminated for labs with high pipetting requirements.
  • Quality: Precision of automated sample preparation exceeds the precision achieved by multiple analysts across shifts which improves the quality and reliability of results. The repetitive nature of automation is more consistent than manual preparation which reduces the risk of analyst errors. This in turn lowers laboratory costs by reducing rework and lowers the risk of price concessions for off-spec product due to lab error for the client.
  • Environmental: Small scale sample preparation reduces waste volume which lowers disposal costs. Waste reduction of >50 percent is typical. This approach also supports green waste reduction initiatives such as CMA’s Responsible Care® program and ISO 14001.

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Published: October 1, 2009

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