Mass Spectrometry has recently undergone a transition from purely research discovery scale applications to rapid high-throughput screening platforms. As research and clinical investigations have grown in size and complexity, so have the capabilities of MS instruments to analyze large numbers of test samples. In many cases, however, the sheer number of samples has overwhelmed the MS workflow of testing labs, such as those involved in proteomic research, as well as clinical, forensic, and toxicology analysis.
A common bottle neck in the MS workflow is the sample preparation stage, during which primary samples are treated, analytes are extracted and enriched, and buffers are often exchanged for compatibility with LC-MS or MS instrumentation. Sample prep may involve any number of techniques and products either for manual or automated processing. Likewise, there are many products for sample filtration, precipitation, solid phase extraction SPE, and pass through enrichment processing, both at the single sample and 96-well microplate scale.
Solid Phase Extraction (SPE), or technically known as liquid-solid phase extraction, is a sample prep technique which incorporates chromatographic material such as reversed phase sorbent in the clean up process. SPE functions to remove matrix materials from blood, urine, cell lysates, etc, thereby enriching small molecules, metabolites, drugs, and other analytes for MS analysis.
Waters offers a wide selection of SPE products, including the Oasis brand cartridges and plates, for targeted removal of contaminant materials, designed to reduce ion suppression and enable sensitive detection of small (trace) levels of compounds. The Oasis line includes: Oasis HLB reversed-phase hydrophilic polymer ideal for a range of analyte chemistries; the Oasis Prime HLB technology for simplified sorbent conditioning, equilibration and sample processing; and the MCX, MAX, WCX, and WAX products, which make use of distict chemical interactions for more selective extraction. The Oasis brand of products and kits are proven and popular throughout the MS community for a range of applications.
Agilent offers the Bond Elut and Captiva lines of SPE products for rapid sample prep in cartridge and 96-well plate formats. The Bond Elut technology is designed to support a wide range of selective SPE techniques by using a catalog of unique polymeric sorbent materials. Bond Elut products are also meant to make the transition from pilot scale to microplate scale processing easier and faster.
To facilitate processing of microplate scale sample arrays, there are a number of products including plate vacuum and positive pressure manifolds. These products can dramatically increase the speed and throughput of SPE plate (and other sample prep plates) processing by multiplexing and accelerating this stage of the MS analysis workflow.
Beyond the transition from single sample to microplate processing, the next jump in scale is to automated microplate processing for MS analysis.
Tecan offers products to serve sample prep at the microplate level. These include microparticulate sorbents such as the TICE technology and others designed for sample cleanup and enrichment for a broad range of MS workflows and applications. Semi-automated positive pressure workstations such as the RESOLVEX line are optimized for use with their RESOLVEX smart extraction consumables as well.
Automated liquid handing solutions for clinical analysis include dilute and shoot, for simple urinary drug screening, and liquid-liquid extraction for rapid precipitation of background matrix materials in more complex samples. The Freedom EVO automated workstation can be outfitted with multichannel liquid handling, reagents carriers, tube racks, bar code readers, shaking stands, and LCMS data conversion tools to suit specific applications. The technologies and products are designed to easily integrate sample prep procedures and automated liquid handing solutions for true high throughput MS applications.
The many technologies and products available assist in lowering sample complexity and enriching sample analyte concentrations -- necessary processes to support the sensitivity and selectivity of MS workflows. The continued development of effective sample prep solutions serve to lower the barriers of speed and versatility of MS analysis -- enabling a greater range of research and clinical testing possibilities to be realized.