Solid phase microextraction, or SPME, is a sample preparation technique used both in the laboratory and on-site. Developed in the early 1990s at the University of Waterloo by Dr. Pawliszyn's group, it is a simple and inexpensive technique where the use of solvents is not necessary.
SPME can be thought of as a very short gas chromatography column turned inside out. SPME involves the use of a fiber coated with an extracting phase, that can be a liquid (polymer) or a solid (sorbent), which extracts different kinds of analytes (including both volatile and non-volatile) from different kinds of media, that can be in liquid or gas phase. The quantity of analyte extracted by the fiber is proportional to its concentration in the sample so long as equilibrium is reached or, in case of short time pre-equilibrium, with help of convection or agitation. After extraction, the SPME fiber is transferred to the injection port of separating instruments, such as a Gas Chromatograph, where desorption of the analyte takes place and analysis is carried out.
The attraction of SPME is that the extraction is fast and simple and can be done without solvents, and detection limits can reach parts per trillion (ppt) levels for certain compounds. SPME also has great potential for field applications; on-site sampling can be done even by nonscientists without the need to have a GC-MS at each location. When properly stored, samples can be analyzed days later in the laboratory without significant loss of volatiles.
Solid phase microextraction is a fast, solvent less alternative to conventional sample extraction techniques. In SPME, analytes establish equilibria among the sample matrix, the headspace above the sample, and a polymer-coated fused fiber, then are desorbed from the fiber to a chromatography column. Because analytes are concentrated on the fiber, and are rapidly delivered to the column, minimum detection limits are improved and resolution is maintained. SPME is compatible with analyte separation/detection by gas chromatography or HPLC, and provides linear results for wide concentrations of analytes.
SPME is an equilibrium process based upon Fick’s 1st law of diffusion
SPME is a technique where the sample is incubated or agitated to equilibrate the headspace. A SPME fiber is then introduced to the headspace for a predetermined period of time. The SPME fiber is then transferred to a hot GC injection port. Analytes that were adsorbed to the fiber from the sample headspace are desorbed directly in the GC inlet. SPME fibers are a distributed by Supleco and are available in a wide variety of polarities. By matching fiber polarity with target analyte characteristics, the analysis can be optimized for improved sensitivity and performance.
SPME extraction for heated and agitated samples
For use with standard SUPELCO SPME fibers
Septumless Injector and SPME liners recommended
SPME offers some important advantages:
- Single Step Extraction - reduces sample preparation time by 70%
- Versatility - various selectivities available, adapts to any GC or HPLC system, can be automated
- Efficient & Economical - little/no use of solvents, quantitative method, allows more than 50 extractions per fiber on average
Comparison of SPME to SPE
SPE exhaustively extracts all of the analytes, but they are diluted during elution 1mL of sample containing 1µg/mL of analyte passed through tube, eluted with 1mL of solvent = 1µg/mL X 1µl injection = 1ng (Concentrating to 100µl or injecting 10µl = 10ng on column
Dual SPME is now possible
LEAP now has the ability increase SPME throughput with Chronos Scheduling software
This is performed with a Dual Rail SPME extraction and injection to a GC. Synchronization with the GC can be integrated with Chronos or with contact closure. To achieve optimal throughput, the second arm will be prepping with SPME on separate tray while the previous GC run is in progress. This allows "Prep Ahead" functionality never before capable.
SPME on the PAL Uses Windows Media Player to view
LEAP Technologies provides fully automated sample processing workstation instrumentation solutions based on the LEAP CTC PAL X, Y, Z syringe only autosampler robot. This extremely flexible, precise, and adaptable liquid handling robotic platform is available in a variety of lengths and options depending on the requirements of your sample preparation and injections for your UHPLC, LC or GC chromatography. LEAP also offers process control systems and stand alone workstations. LEAP is an open, neutral resource for technical support of existing PAL. Keep your PAL in peak working order LEAP offers full support and service for the PAL platform with over 11 years of history with the PAL. LEAP can also write custom macros, cycles, and scheduling software for your specific applications. We're proud that LEAP is known as a productivity improver for laboratories including government labs in agencies such as FDA, USDA, EPA, FBI, Armed Forces, Homeland Security and others function more efficiently. Robotic sample prep equipment works well in government labs and challenges lab technicians to keep feeding those more samples. Analytical equipment such as chromatographs and mass spectrometers are expensive devices and also expensive to maintain. LEAP can help to keep them running and analyze samples around the clock. LEAP has most of its laboratory automation robots under GSAcontract and is eager to service and maintain everything it sells to keep your expensive lab equipment running around the clock. CTC Analytics Combi PAL and HTS PAL for Front-End Automation for LC and GC applications. LEAP offers customized on-site training. LEAP Is continuing to develop FAQ, Solutions, Tips & Techniques,a Learning Center with the LEAP Wiki for the benefit of all PAL Platform Robotic users. We will continue exceeding customer expectations for quality, cost effective and efficient results using the most current technology and expertise in our industry. Our aim is to be the ultimate knowledge base on everything related to the PAL. LEAP is known as the autosamplerguys being in business over twenty years. LEAP has extensive multi-vendor experience with integrating the PAL. HTX, HTS, HTC, HTX-xt, HTS-xt, HTC-xt, LC-Mini, Combi PAL,COMBI-xt PAL, and GC PAL models. We have the Quality, Training, Parts availability, Infrastructure, and Experience.LEAP is sometimes referred to as an Application Automation House who is continually adding new products and solutions to its Lab Automation line. As we do so we change the content of this web site so please check back.
Please contact LEAP Technologies on how we can help you get maximized throughput with flexible pipetting automation solutions whether it is our standard applications or customized to your needs. The Combi-xt PAL autosampler is able to perform liquid and headspace analysis. Headspace options include Solid Phase Micro-extraction (SPME) and ITEX-2 as alternative to purge and trap. The HTS-xt PAL autosampler dramatically increases sample throughput by offering automated sample prep, Peltier cooled and heated sample storage using the cooled stack, Peltier cooled and heated sample storage using the cooled stack and low carryover due to the self-cleaning DLW (Dynamic Load and Wash) module and L-Mark syringes, peltier cooled valves and columns. LEAP provides automation that fits your needs and reduces errors, increases sample capacity, increases efficiency, reduces cost by supplying long term productivity improvements with user friendly software and flexible hardware. LEAP performs just in time or on time sample prep and inject. LEAP offers full support of integrated and non-integrated PAL software with both sales and support for Cruise Control, Cycle Composer and Cycle Composer Macro Editor, Agilent ChemStation CTC Control, Mass Hunter and EZChrom CTC integration, Xcalibur, Waters Masslynx or Analyst CTC Control software, Thermo (Finnegan) XCalibur, LEAP Shell, and Chronos software. The PAL is more than just an autosampler, it is a high-quality and efficient laboratory robot platform that can be customized by LEAP Technologies to meet your specific needs.
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