New Sample Preparation Products and Accessories at Pittcon 2015

This yearly report on new products introduced at Pittcon (or in the preceding year) covers sample preparation instruments.

As expected, the new products introduced in the past year in the area of chromatographic sample preparation, while somewhat limited, mirror the current development in the field. That is, a few systems were developed to automate or streamline the sample preparation process; new sorptive phases and formats, including QuEChERS (quick, easy, cheap, effective, rugged, and safe), were developed; and accessories and other stepwise advances in the field were noted. In late 2014, the LCGC editorial staff submitted a survey to vendors of sample preparation products. Responses to this survey are compiled in this review. Additionally, a keyword search using the terms "sample preparation" and "extraction" was conducted for exhibitors at Pittcon 2015; then each of these vendors was visited. While attempts were made to be as inclusive as possible, we apologize for any oversight.

Hollow-Fiber Microextraction

Perhaps the highlight among new sample preparation products is an unheralded introduction by one of the smallest vendors. Biomics, Inc., brought forth devices for hollow-fiber microextraction (HFME) at Pittcon 2015. HFME has been developed for quite some time (more than a decade) and is performed in a variety of configurations; for example, it was reviewed in a 2010 "Sample Prep Perspectives" column (1). Biomics claims that their hollow-fiber product, available in single-vial and 96-well formats, is the only commercially available HFME product. Regardless of the validity of this claim, such products are certainly scarce and this development by Biomics should drive the acceptance of the technique. Figure 1 shows an example of the format of a 96-well plate HFME device. The HFME approach should work for the isolation of environmental, pharmaceutical, food, and nutraceutical samples.

Figure 1: Hollow-fiber microextraction in a 96-well format: (a) the plastic base, (b) the attachment of hollow fiber to the plastic base, (c) the 96-well plate, and (d) an expanded view of the hollow-fiber device. 1 = hollow-fiber attachment tip, 2 = donor phase collection tip, 3 = acceptor phase, 4 = donor phase, 5 = hollow fiber. Adapted with permission from reference 2.

Systems

Several sample preparation systems were introduced in the past year, typically with multisample capabilities and generally in the bioanalytical realm.

Similar to the HFME product introduction above, Phenomenex expanded its offerings with the Novum Simplified Liquid Extraction (SLE) product line. Available in both cartridge and 96-well plate formats, these liquid extraction products are designed to replace conventional liquid–liquid extraction (LLE) in bioanalytical, food safety, and environmental testing. In the suggested protocol with the Novum product, a sample is diluted with buffer solution and added to the SLE medium, and after a brief soaking period, elution with ethyl acetate or dichloromethane follows -the process is completed within about 15 min. The Extrahera system by Biotage supports both supported liquid extraction and solid-phase extraction (SPE), in either column (1, 3, and 6 mL) or plate formats. The Extrahera system also can be used in protein-crashing applications and uses positive pressure for more reproducible flow. Added automation to the Fotector Plus automated SPE system (Reeko Instrument USA) provides capacity to run 48 samples continuously with positive pressure sampling and elution modes.

Keeping with developments in the bioanalytical area, the ECO₂Chrom flash chromatograph from Applied Separations uses liquid carbon dioxide to reduce organic solvent use and lower the analyte concentration time. The high diffusivity of the mobile phase allows smaller particle sizes to be used, allowing for greater efficiency or faster analysis times for the same efficiency as with liquid organic solvents. This flash chromatography system accommodates multiple sample introduction formats with time- or peak-triggered fraction collection. Meanwhile, wet or dry homogenization of biological samples can be performed with the Biotage Bead Ruptor 24. The bead mill uses 24 2-mL tubes, 12 7-mL tubes, or six 30-mL tubes simultaneously. The SiliCycle MiniBlock is a general purpose system that allows flow-through parallel processing of chemical reactions, including derivatizations, peptide synthesis, and screening, with resin agitation and washing. The system operates over a temperature range from -20 °C to 120 °C with capacities ranging from six 40-mL vials to 48 4-mL tubes.

Other significant introductions in the area of sample preparation systems were updates or product extensions, especially in systems for environmental analysis. The Pickering Laboratories DEXTech system uses columns with different formats for sample cleanup in the analysis of dioxins and polychlorinated biphenyls. Meanwhile, Horizon Technologies added plungers for greater flexibility to the SmartPrep Extractor automated SPE system and Environmental Express added chemistries to its SimpleDist system for the distillation of phenols. The Omni-Sampler Plus sample handling system from Entech Instruments updated cryogenic preconcentration for volatile organic compounds onto glass beads, with mild temperatures (60–100 °C) for the transfer of C₂–C₂₄ compounds. The Omni-Sampler Plus sample handling system has multiple modes for the determination of volatile analytes, including headspace sampling, thermal desorption, porous cartridge microextraction (a high-capacity version of solid-phase microextraction [SPME]), and on-column trapping. For water analysis, the 4100 Water/Soil Sample Handler from OI Analytical automates sample handling and processing in collaboration with the company's Eclipse 4660 purge-and-trap concentrator.

Sorbents

Various sorbents, in cartridges or as bulk phases, have been introduced in the past year. These phases are designed for SPE, including dispersive SPE (dSPE) approaches such as the QuEChERS method, high sample capability via polymer supports, and selectivity in sample cleanup. These sorbent products are summarized in Table I.

Accessories and Other Products

Several other sample preparation products were recently introduced to the market. Most notably, Supelco continues to develop its SPME product line in the area of biocompatible SPME. This product extension is more compatible with biological analyses such as the direct sampling of small animals like mice, as well as dried blood spot analysis, 96-well plates, and other microsampling situations. Since gas chromatography (GC) and derivatization reactions for GC are often considered mature technologies, it is somewhat surprising to see a new derivatization regent from Regis Technologies. N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) with 1% trimethylsilyl chloride is also marketed by other vendors for the silylation of hindered hydroxyl groups that do not ordinarily react with MSTFA, along with secondary amines, amides, carboxyls, and steroids. Thermo Scientific addresses an expanding number of application areas for accelerated solvent extraction (ASE), particularly polymers, with the offering of ASE extraction thimbles for samples that melt at the operating temperatures used in ASE. The goal is to prevent the plugging of filters and tubing by fine particles by using cellulose or glass fiber filters. The GlycoWorks RapiFluor-MS N-Glycan kit from Waters is a 96-well plate product based on hydrophilic interaction chromatography. The GlycoWorks kit is used for the sample preparation of N-linked glycans released following rapid deglycosylation and labeling to provide enhanced sensitivity for both fluorescence and mass spectrometric determination. Sample analysis of glycoproteins can be completed in less than 1 h. Finally, J.G. Finneran Associates marketed a vial loader for 96-well plates with insert vial sizes ranging from 350-μL glass vials to volumes of 2 mL.

Conclusions

With this review of new product offerings in the field of chromatographic sample preparation, the natural question is: "What's next?" Based on this year's offerings and advancements in the field, it is anticipated that commercial developments in the current year will address several issues. Sorbent-based sample preparation will continue to see significant commercialization in several areas. QuEChERS will remain a growing area and the end of patent protection for SPME will bring new competitors to the field and new areas such as biocompatible SPME and SPME designed for liquid chromatography applications. Other advancements will accommodate serial or parallel sample processing for increased throughput. Bioanalytical and food safety applications will drive these developments.

References

(1) L. Zhao, H.K. Lee, and R.E. Majors, LCGC North Am.28(8), 580–591 (2010).

(2) G. Borijijan, Y. Li, J. Gao, and J.J. Bao, J. Sep. Sci.37, 1155–1161 (2014).

Douglas E. Raynie "Sample Prep Perspectives" editor Douglas E. Raynie is an Associate Research Professor at South Dakota State University. His research interests include green chemistry, alternative solvents, sample preparation, high resolution chromatography, and bioprocessing in supercritical fluids. He earned his PhD in 1990 at Brigham Young University under the direction of Milton L. Lee.

Douglas E. Raynie