Just like any purchase, the number of options available when buying an autosampler can be overwhelming. And there are no easy-to-use web sites that compare features and pricing across multiple vendors like there are with consumer products. Instead you have to obtain brochures, specification sheets, and pricing from every vendor, and then hope you are making proper comparisons.
GERSTEL eliminates these issues by providing autosamplers that can be tailored to your exact needs. We configure a system to maximize your productivity from the simplest to the most complex using a single hardware and software platform.
Let’s take SPME analysis, for example. This is an extremely popular technique that can be used manually to quickly determine specific compounds in a wide variety of matrices. However, once a method is developed and larger numbers of samples need to be analyzed, automation is a must. MPS-type autosamplers are typically used for this where a simple standard method includes only sample heating with agitation followed by fiber desorption in a hot inlet. This can provide adequate results, but now with the new MPS Robotic Autosampler, SPME analysis can be brought to a much higher level of precision, accuracy, and robustness with lower detection limits.
What makes the MPS Robotic so ideal for SPME analysis automation?
The MPS Robotic automates ALL steps required for the method as well as unique options that further improve results. This is accomplished using the new tool-exchange feature where different injection techniques can be incorporated into the method as well as the very important feature of changing the liner to one optimized for SPME. Let’s take a detailed look at the SPME system and how it works.
The MPS Robotic is mounted on a GC that ideally includes a GERSTEL CIS inlet. This inlet includes a septumless sampling head that eliminates septum coring (no pieces of septum in your inlet liner) and also includes a narrow-bore inlet liner tailored to the SPME fiber to optimize fiber desorption. The SPME method is created using Maestro software by simply choosing method parameters from SPME-specific screens that allow even advanced features such as pre- or post-fiber derivatization to be selected. On screen help provides guidance on parameter ranges with advice on how to optimize these parameters. If the method requires the preparation of standards, calibration curves, or the addition of an internal standard or other reagent, this can all be automated by the analyst through the use of Maestro sample prep functions.
Here is a step by step example of a highly optimized SPME method:
1. Unlike other software packages used for SPME analyses that don’t make you aware of problems until samples are run, the first thing Maestro does is to check all parameters and procedures beforehand and guides you through the proper correction steps.
2. Next, Maestro optimizes the sample preparation steps in order to have as many processes running simultaneously as possible — providing maximum time efficiency. We call this “PrepAhead.” The screen shot from the Maestro sample scheduler below shows how the samples are run if the PrepAhead function is turned off (this is how other software packages would work). Note each step is performed sequentially, nothing is done in parallel.
The next screen shot shows how Maestro handles the method. Note sample preparation steps are overlapped and the time it takes to run the same number of samples in cut in half. The clear visual layout of the scheduler also lets you optimize the PrepAhead feature and provides a real time indicator of the sample sequence’s progress.
3. Prepare calibration curve standards using appropriate liquid handling tools.
4. Add internal standards or any other reagents (salts, acid, base) to sample vials.
5. Change liquid handling tool to GC liquid injection tool.
6. Inject calibration standards into GC to obtain calibration curve data.
7. Incubate sample — Maestro allows sampling directly from a tray, from a heated agitator, or from a heated stirrer. The GERSTEL unique stirrer allows the sample to come to equilibrium much faster and has the added benefit of not stressing the fiber during extraction.
8. Change inlet liner to SPME liner.
9. Exchange liquid injection tool to SPME tool.
10. Load derivatizing agent onto fiber.
11. Move SPME fiber to sample vial for extraction.
12. Move and insert SPME fiber to inlet and desorb compounds from fiber onto the GC column.
All the analyst has to do is load samples and reagents and walk away. This dedicated system will provide the highest quality results in the shortest period of time, and since the MPS Robotic is one of the most reliable autosamplers ever made, it can provide around the clock results increasing even further the productivity of your laboratory.
Reach out for a conversation about how to improve the efficiency of your own lab with automated sample preparation.