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As a business segment, chromatography is still the largest single technology segment ($8 billion global sales) in the chemical and life science laboratory space ($48 billion annual sales). Still, at Pittcon 2017, the number of products fitting under the separation science umbrella, especially from the major vendors, was unusually low. Possibly, developers are working on new platforms to take advantage of advances in column technology and micromachining, including 3-D printing.
Figure 1 – Section of 2-meter-long capillary column for HPLC with micromachined pillars in place of particles. The flow path is etched into the chip, ~ 2 × 5 cm. (Image courtesy of PharmaFluidics.)What might be on the drawing boards? Historically, column technology has led instrument design. PharmaFluidics (Ghent, Belgium) was one of 128 firms exhibiting for the first time at Pittcon. The company, which commercializes the inventions of Prof. Gert Desmet of the Vrije Universiteit Brussel, has developed pillar array columns for LC/MS (Figure 1). The column’s uniform flow profile, made possible by micromachining, yields separation units that outperform capillary packed columns for LC/MS in structural biology. The pillars are machined into a solid surface about the size of a microscope slide. Using a folded channel design, the separation channel can be as long as 2 meters. Traditional surface chemistries such as C18 can be bonded to the pillars for retention. I inquired about dispersion of the peak from the racetrack effect at the folds of the channel; this is eliminated through proprietary design elements.
Figure 2 – Gradient elution pumps, mixer, and injector for nanoflow UHPLC. (Image courtesy of VICI Valco.)Analyzing the biome can entail complex chromatograms. The μPAC column from PharmaFluidics seems to be up to the task. One example showed a very busy high-resolution chromatogram with MS detection. Run time was 275 minutes. Pmax was less than 300 bar pressure.
VICI (Houston, TX) introduced a highly engineered integrated fluidics module that includes dual syringe pumps, a mixer, and an injector for nanoflow UHPLC (Figure 2). The targeted application is the mounting of a nanoflow UHPLC around the inlet of nearly any MS. Current LC/MS units involve transfer lines between the LC and MS, which dilute and delay. The fluidics module avoids all that; in addition, capillary columns, such as those from PharmaFluidics above, fall into the nanoflow region. With nanoflow, significant improvements in detection limit from the MS are expected. For high-throughput applications, I expect the integration of a micro-autosampler. VICI’s business model is to market modules and components to instrument vendors.
These key enabling technical benchmarks—the fluidics modules and the pillar array columns—should lead to reduced costs, lower environmental impact, and higher resolution and productivity in LC assays. How soon? Look for first products incorporating these technologies in about two years. Beyond these key products, vendors showed several new and unique instruments and columns, etc.
Instrumentation for LC
Agela Technologies
Figure 3 – Octopus preparative HPLC for sample fractionation. (Image courtesy of Agela Technologies.)Agela Technologies (Wilmington, Del.), a Danaher company, introduced the Octopus modular HPLC purification system for lab-scale fractionation and prep (Figure 3). UV absorbance, UV/VIS, photodiode array, evaporative light scattering, and refractive index detectors are available.
Pumping systems offered include binary and quaternary gradient elution with maximum flow of 200 mL/min. The fraction collector module contains four vial racks with up to 180 tubes. Operating software is based on Windows 7.
Bruker and Spark Holland
Bruker (Billerica, Mass.) is known for its broad MS product line and nuclear magnetic resonance (NMR) technology. Ultrahigh-performance liquid chromatography (UHPLC)-MS and UHPLC-NMR are hyphenated instruments that beg for a UHPLC from the same vendor.
For four decades, Spark Holland (Emmen, The Netherlands) has been supplying premium-performance modules for HPLC through OEM arrangements, and is best known for its autosamplers. This year the company introduced the SPH1299 UHPLC pump, which uses four independently driven reciprocating pumps to deliver mobile-phase concentrations with high accuracy and precision at pressures up to 18,850 psi. The pressure ripple is less than 1% of operating pressure or less than 75 psi, whichever is greater. A priming pump quickly sucks the mobile phase to the high-pressure pumps during startup, and a solvent degasser is integrated into the flow path.
The new Bruker Elute LC series features a Spark Holland SPH1299 binary gradient pumping module. Looking ahead, Bruker intends to add other modules or accessories such as the CTC PAL3 autosampler (LEAP Technologies, Carrboro, N.C.) for the EluteHT (high throughput) to further extend system capabilities. The company also offers the Elute OLE, a version optimized for the online extraction of analytes from water or urine.
Cromite
Figure 4 – Expanded view of compact, portable Cromite HPLC. The base houses electronics, communications, and optics. Samples are introduced on the side with a novel sorbent. The chromatography column clicks into the base; the mobile phase reservoir (right) fits over the column to form a compact instrument. (Image courtesy of Cromite.)Cromite’s (Wheeling, Ill.) prototype chromatograph (called the Cromite, Figure 4) was generated with a 3-D printer. The top of the instrument is a mobile phase reservoir; the bottom contains the pump, injector, column, and a UV/VIS absorbance detector with a 4-μL cell. Noise level is less than 0.05 mAU. The combined unit weighs only 2.5 pounds. Power is 15 V DC, 15 W. Column flow is a unique two-pass design in which the mobile phase flows up and back to the detector. This avoids long transfer lines. Target applications include on-scene, forensic drug analysis; food identification and adulteration; and at-site monitoring of chemical production processes. The company notes that many HPLCs run the same assays 24/7. Although the Cromite is not very flexible, it is simple to use and offered for routine quantitative work. Its low price makes it possible to dedicate a chromatograph for each assay and location.
FF Runge GmbH
Mikron LC detectors from FF Runge GmbH (Potsdam, Germany) have UV/VIS, fluorescence, and conductivity detection modes. The mikron 31 photometer uses LED light sources to select the wavelength from 240 to 1050 nm. Specs include: bandwidth, <15 nm; noise, <10-5 AU at 1 sec TC (time constant); flow cell volume, 10 μL; and pathlength, 10 mm. Unit size is 5.9 × 1.3 inches.
The mikron 71 fluorimeter consists of modular elements for λex (240– 650 nm) and λem (350–800 nm). Flow cell volume is only 5 μL. The entire unit is only 6 inches long, including power supply, flow cell, and light detection and signal processing units. The mikron 81 conductivity detector has the same profile but is only 3.1 inches long. It calibrates at startup, and identifies the cell constant.
Sedere
Sedere (Alfortville, France) introduced the SEDEX LT-ELSD (evaporative light-scattering detector) for low-temperature applications in supercritical fluid chromatography (SFC), UHPLC, and HPLC. The LT model is optimized for evaporation of low-boiling-point mobile phases. Further improvements include a new high-power laser, which improves signal-to-noise. New software extends the dynamic range to more than 105. Sedere offers a detection cell specifically designed for SFC using carbon dioxide.
Shimadzu
Three new liquid chromatography analyzers were introduced by Shimadzu (Columbia, Md.). The PPSQ-51A/53A automates Edman degradation with an isocratic HPLC. Isocratic operation facilitates recycling the mobile phase, which reduces waste and cost. The software is FDA 21 CFR Part 11-compliant.
The LC/MS/MS Method Package for Cell Culture Profiling simultaneously analyzes up to 95 analytes commonly found in cell culture.
Shimadzu’s Cannabis Analyzer for Potency includes HPLC software and consumables with three application-specific workflows for the reliable assay of cannabis samples. Installation (including validation) and training can be done in one day.
Thermo Fisher Scientific
Vanquish Flex Binary UHPLC from Thermo Fisher Scientific (Waltham, Mass.) uses two independent metering pumps combined with high-pressure mixing to offer the most rapid gradient response. The binary gradient system will appeal to labs developing or troubleshooting analytical methods or applications that require a biocompatible mobile-phase flow path.
HPLC and UHPLC columns
ES Industries
Chiral separations by HPLC and SFC are still rather empirical. Some enantiomers are difficult to separate with existing columns, which justifies adding more stationary phases. ESI (West Berlin, N.J.) introduced ChromegaChiral CCX, which is phenyl amylose coated, not bonded, to silica spheres that have been previously bonded with a combination of methylbenzylcarbamate and 3,5-dimethylphenylcarbamate. The bonded carbamates stabilize the amylose coating and improve durability. ESI showed a 9-minute SFC separation of methaqualone.
ChromegaChiral CCU is a column chemistry in which 3-chloro-4-methylphenylcarbamate and methylbenzylcarbamate are bonded to amylose, which is coated on porous silica spheres. This produces a robust column packing with unique selectivity. One application example showed the SFC of enantiomers of the herbicide benoxacor.
The Epic SCX (strong cation exchange) stationary phase is for the separation of organic bases such as cytosine and adenine. Aromatic sulfonic acid groups are bonded to spherical silica particles to give a capacity of 3 meq/g. Nominal sizes are 1.8, 3, 5, and 10 μm.
MacroSep Bio-Gold premium-performance HPLC columns are designed to take advantage of new ultrahigh-purity spherical silica, which greatly improves acid and alkaline resistance. The silica has a wide pore suitable for biologics sized between 10 and 100 kD. Bio-Gold comprises 10 bonded phases, with endcapping, on 1.9-, 3-, 5-, and 10-μm silica spheres. The columns can be regenerated with short washes of NaOH. Surface chemistries include MacroSep Bio-Gold C4, C8, C18, naphthyl, biphenyl, diphenyl, HPR (perfluorinated alkane), and PFP (pentafluorophenyl). The unique HPR chemistry uses perfluorinated aliphatic groups designed to separate based on fluorophilic interactions with new fluorine-containing active pharmaceutical ingredients (APIs).
Fortis Technologies
Fortis Technologies Ltd. (Cheshire, U.K.) was an early promoter of core-shell stationary phases. The company’s line continues to expand with SpeedCore BIO Peptide C18 (160-Å pores), Protein C18, Protein C8, and Protein C4 (all with 300-Å porosity). These columns are suitable for mobile phases in the pH range 1–8. The SpeedCore pH Plus C18 is now rated for operation at pH 2–11, which can be useful for basic compounds. Selectivity of the RP18-Amide is often orthogonal to pure reversed-phase liquid chromatography (RPLC).
Nacalai USA
Nacalai USA (San Diego, Calif.) displayed pentabromobenzyl (PBr) surface chemistry bonded to Cosmosil porous silica (5 μm, 120 Å) and Cosmocore 2.6-μm solid-core particles (~90 Å). According to the company, the PBr phase provides better retention and capacity for polar compounds using RPLC conditions than hydrophobic interaction liquid chromatography (HILIC). The PBr phase offers greater selectivity than C18 phases for aromatics such as nucleic acid bases, B vitamins, and phenylalanine.
PolyLC
For years, PolyLC Inc. (Columbia, Md.) has focused on developing column packings for bioseparations, including proteins, amino acids, peptides, and glyco forms. This year, Andy Alpert, founder and president, presented a lecture on columns for top-down proteomics using hydrophobic interaction chromatography (HIC). It is fair to say that HIC is one of the least popular modes of HPLC. However, HIC does preserve the native structure of proteins better than most other modes.
Traditionally, for HIC, one runs a reverse salt gradient elution with ammonium sulfate. Ammonium sulfate is not compatible with mass spectrometry. While ammonium acetate is MS-compatible, it affords inadequate retention with conventional HIC materials. A new series of HIC materials from PolyLC makes its use practical. Several HIC-MS applications were shown using PolyPENTYL A (2 or 3 μm, 1500 Å) in a 100 × 0.2-mm capillary. A Bruker maXis Plus Q-TOF gave the mass spectra. Applications included several protein standards such as ribonuclease A, trypsinogen, and lysozyme. The parent and fragment ions were consistent with previously reported values, and the mass spectra were typical of proteins with native structure intact. Alpert also looked at monoclonal antibodies and an antibody-drug conjugate (ADC). Variant glycoforms were identified, and the spectrum of the ADC clearly showed the number and mass of drugs conjugated to the antibody via the linker. PolyLC makes a range of columns for HIC with ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl ligands.
Restek
Force premium-performance silica-based HPLC and UHPLC columns from Restek (Bellafonte, Penn.) feature biphenyl, endcapped C18, and pentafluorophenylpropyl surface chemistries. Phase selectivity is the same, irrespective of particle size. Columns packed with larger particles (such as 3 or 5 μm) give wider and shorter peaks than 1.8 μm (but the pressure drop is lower) and are compatible with legacy HPLC instruments. Method transfer from UHPLC to HPLC is easier. The silica is robust, with a Tmax of 80 °C and operating range of pH 2–8. One study showed no loss of efficiency after 1000 injections at 12,000 psi.
Shiseido
Shiseido (Tokyo, Japan) CAPCELL CORE columns have a 2.7-μm solid-core particle with a 0.5-μm shell of porous silica with a 90-Å pore. Surface chemistries include bonded C18, C27, PC (propylene carbonate) (zwitterion), PFP (pentafluorophenyl), and ADME (adamantylethyl). The C27 is most unique—it is compatible with 100% aqueous eluents and has stronger retention of polars than C18. The selectivity of the ADME phase differs significantly from the C18 and C27 phases. CAPCELL columns are available from JM Science (Grand Island, N.Y.).
Showa Denko
Traditionally, chromatography of amino acids, carbohydrates, and organic acids requires three different columns and runs. Showa Denko (New York, N.Y.) Shodex HILICpak VG-50 2-D HPLC columns resolve these analytes in a single 20-minute run. The column packing has a tertiary amino group bonded to 5-μm polyvinyl alcohol particles with a 100-Å pore. A related column with a bonded COOH group—the VC-50 2D—is recommended for separation of neurotransmitter, aminoglycosides, and antidiabetics.
Over decades, Showa Denko has developed a wide range of columns for steric exclusion chromatography (SEC). The LW-803, introduced this year, is specifically optimized for the analysis of IgGs. This column is a 3-μm silica bead in 300 × 8 mm. Run time is 15 minutes. For polystyrene polymers, the company introduced a new column packed with a very narrow-range polymer bead for high-range gel permeation chromatography (GPC). The HK-404L can resolve polystyrene standards from 127,000 D down to 580 D. It is suitable for GPC of polysulfones, polyvinylacetates, and polycarbonates.
Tosoh Bioscience
Tosoh Bioscience (King of Prussia, Penn.) introduced the TSKgel Protein A-5PW for analysts working with antibodies. Protein A has very high bio-affinity for antibodies. One application showed capturing and eluting an antibody in less than 2 minutes. The column won a Bronze Pittcon Today Excellence Award.
Welch Materials
Ghost peaks appear in a chromatogram, even when no sample is injected. Tracing them to their origin for elimination is time-consuming, and resolving the problem is expensive and/or impractical. Welch Materials (Shanghai, China) has developed a highly retentive column that is mounted between the mixer and injector. This traps the impurities from the gradient system. Ghost-Buster columns are packed with Ultisil XB-C18 (4.6 × 250 mm) from Welch. Ultisil Bio-UHPLC columns provide a PEEK flow path encased in stainless-steel housing, and are packed with C4, C18, or SEC bonded to 1.8-μm silica spheres with a 300-Å pore. The columns are packed at 20,000 psi, and service is rated to 15,000 psi.
YMC America
The growing importance of antibody-derived therapeutics has attracted the attention of column vendors. For example, the YMC-PACK Diol 2 μm was introduced by YMC America (Allentown, Penn.) for rapid gel filtration of proteins. The column packing starts with 2-μm silica spheres with 200-Å or 300-Å pores. Suggested mole weight limit is 300,000 or 1,000,000 D, respectively. Nominal particle size is 2, 3, or 5 μm. The smallest particles give the highest column efficiency and, hence, the highest resolution. Sample is protected from the nonspecific adsorption of proteins. Importantly, the separations scale with particle size.
LC accessories
FLOM
Overflowing waste crocks are a common and potentially dangerous issue with liquid chromatographs, especially with unattended operation. FLOM’s (Tokyo, Japan) Sonic Reservoir Sensor (SR-13) monitors reagent and waste levels in real time. It mounts in the cap of the container. The handheld controller monitors inputs from the umbilical cord to each reservoir.
Mott Corp.
Historically, low-dead-volume dynamic mixers have been used to mix mobile phases during gradient elution in HPLC. Mixer volume needed to be tuned to instrument flow rate: too large and the response was slow; too small and mixing was not complete, which perturbed peak shape and often increased baseline noise. Mott Corp. (Farmington, Ct.) used metal 3-D printing to develop mixers for both pre-pump and high-pressure gradient modes. The mixers were modeled using computational fluid dynamics that created fluid paths with varying length and width designed to create eddies and turbulent flow modes. This resulted in reduced baseline oscillations with one-third the internal volume. Pressure drop is less than 50 bar at 1 mL/min. Mixing volumes are 30, 60, 90, and 180 μL. The larger volumes are useful with pre-pump gradient modes.
Ion chromatograph
Sykam’s (Eresing, Germany) Ion Chromatography System S 150 features an automated conductivity suppressor with overpressure protection. Working range of the conductivity detector is 20 nS/cm to 20,000 μS/cm. The metal-free liquid flow system pump is rated for ±0.1% precision at 1.00 mL/min with a Pmax of 6000 psi. Quaternary gradient elution is optional. Sykam’s Ion Chromatography System S 153-A Dual is designed for the simultaneous assay of anions and cations. The autosampler includes a unique eight-port sample-injection valve (S-6165) that loads the anion and cation loops with the same sample. Anions are separated with an isocratic pump, column, and detector cell; cations are separated with another pump, column, and detector cell. The S 5300 sample injector is compatible with a range of vial racks and multiple-well plates.
Eluent preparation system for IC
Ion chromatography needs pure water for the mobile phase. A poster presented by Estelle Riche and colleagues at MilliporeSigma (Billerica, Mass.) described a two-stage purification of tapwater to ultrapure water suitable for mobile phase for ion chromatography of anions and cations in foods and beverages. The first stage uses reverse osmosis and electrodeionization followed by irradiation with a bactericidal UV lamp to produce “pure water.” This is collected and stored. As needed, the water passes through the new Milli-Q IQ 7000 system, comprised of Jetpore ion-exchange resins and new, fast-kinetic, IQnano ion-exchange resins. This is followed by an excimer-based (mercury-free) UV oxidation lamp, then a second series of purification steps, including activated carbon, followed by more of the IQnano ion-exchange resins. The final stage is filtration using a Millipak 0.22-μm filter in the dispenser.
Gas chromatography instruments
Activated Research Company
Methanizers have an interesting history, particularly for gas chromatography detection, where they convert CO2 to methane and feed the product to a flame ionization detector. Activated Research Company (Eden Prarie, Minn.) introduced the Polyarc system for gas chromatographic detection of carbon-containing compounds last year. Response has been enthusiastic, particularly since chromatographers found that splitting post-column flow between a Polyarc and a mass spectrometer lets the MS assay the peak identity and the Polyarc improve quantitation, which was not reported last year. Polyarc facilitates elimination of tedious calibration of many analytes.
Defiant Technologies
Defiant Technologies (Albuquerque, N.M.) updated its field-portable GC to the FROG-5000. It is designed to measure volatile organic compounds (VOCs) in air, water, or soil. When the FROG launched in 2011, it was the first commercial GC system to incorporate microelectromechanical system (MEMS) components, making it the smallest, most lightweight commercial GC available. Users appreciated the coupling of intuitive software and distinctive design. The new unit features longer battery life, a simpler interface and updated electronics.
Ellutia Chromatography Solutions
Ellutia Chromatography Solutions (Ely, Cambridgeshire, U.K.) introduced the 500 Series ALGas Chromatograph, which has half the footprint of the Series 200, but still maintains a large column oven with a Tmax of 380 °C. Air ovens consume a lot of energy, but the 500 uses a heat exchanger that saves energy. It also supports resistively heated capillaries, which further reduces power consumption while facilitating high-speed temperature programming. This cuts cycle time by a factor of 10.
Gasera
Formaldehyde is everywhere, yet is a recognized carcinogen with a toxic threshold starting at about 100 ppb. NIOSH recommends an occupational exposure level of no more than 16 ppb. Gasera’s (Turku, Finland) ONE FORMALDEHYDE is a GC equipped with a patented cantilever photoacoustic detector. The instrument offers a detection limit of 1 ppb for formaldehyde.
Nanova Environmental
Nanova Environmental, Inc. (Columbia, Mo.) introduced the NovaTest P100 Portable 2-D gas chromatograph, which is optimized for at-site environmental assays, particularly of semivolatile organic compounds. About the size of a brick, the compact unit contains the columns, heart-cutting valve and photoionization detector (PID) with 10.6- or 11.7-eV light. Helium is the preferred carrier gas. A lithium ion battery provides power for more than 8 hours at 24 V dc. The P100 can detect as little as 10 ppt of benzene in air. Twenty years ago, when 2-D GC was a hot research topic, many questioned if it had any compelling applications. As the technology improved, applications—including biofuels, odors and fragrances, biomarkers in breath, and food spoilage—began to fall into place.
Scion Instruments
The Scion Instruments (Austin, Texas) Rapid Gas Analyzer is based on the 456-GC. Some configurations are specifically optimized to fit the unique requirements of standard methods, or particular sample streams. In many cases, reference methods have not kept up with improved technology. Three injector/column and detector configurations are supported by Scion’s CompassCDS software for control and reporting.
Thermo Fisher Scientific
The Orbitrap MS from Thermo Fisher Scientific has been used in LC/MS for almost a decade. This combination is responsible for many advances in life science research, particularly proteomics. When the Orbitrap was introduced, I asked if it would also work in GC/MS, and was told that it was probably overkill for GC. Thus, I smiled when I saw the Exactive GC Orbitrap GC/MS. It seems to be focused on nontargeted assays where the high resolution and accurate mass might help narrow the range of unknowns. The GC is a Thermo Scientific TRACE 1310.
VICI Valco
Most GC assays are run on big-box instruments, with large air bath ovens. These big boxes are optimized around designs and materials of construction that were appropriate in the 1960s. The air bath oven is a prime example—it requires more than a kilowatt of electrical power. Connectors and fittings for gas flows are another obsolete design technology. But, it is the column technology that usually sets the pace.
With this in mind, I attended a lecture session on fast GC. Stan Stearns, president of VICI Instruments, pointed out that subminute GC chromatograms are possible with low thermal mass columns. For example, thin (100-μm-i.d.) capillaries and a heating wire are wound together on a ¾-inch mandrel at a heating rate of 1200 °C/min. Because the low-wattage column heater was not compatible with the injector and transfer lines, engineers developed a small four-zone heater power supply. This permitted active control of the injector, column, and transfer lines from the injector and to the detector. An eight-component assay was complete in 13 seconds with a column temperature ramp of 800 °C/min. Peak width at half height was 120 milliseconds. A simulated distillation of petroleum from C5 to C44 was complete in two minutes. Cool-down is also rapid.
A second paper from VICI discussed new technology required for connections and injection valves. The thin capillary columns are intolerant of dead volume or misaligned flow paths. Fittings of 1/16 and 1/32 inches were replaced with 360-μm (~1/64-inch) tubes and fittings; 360-μm tubing needs special technology to cut and electropolish the ends to reduce dead volume. A new injection valve design reduces peak width to 8 milliseconds. This enabled a BTEX (benzene, toluene, ethylbenzene, and xylene) assay to be completed in 2.5 seconds (Figure 5).
Figure 5 – Ultrafast chromatogram of BTEX. Time is in seconds. (Image courtesy of VICI Valco.)Supercritical fluid chromatography instruments
The Shimadzu Nexera UC won the Pittcon Editors’ Gold Award in 2015. This year, Kenichiro Tanaka et al. presented a poster illustrating the power of the hybrid instrument for the analysis of mycotoxins in foods, including corn and peanut butter. The workflow is simple: 1 gram of peanut butter is mixed with 1 gram of adsorbent and is placed in the supercritical fluid extraction (SFE) tube. After on-line SFE, the SFC stage of the Nexera elutes the extract to the analytical column (4.6 × 150 mm Cosmosil NAP, 5 μm, Nacalai USA), and then to a Shimadzu 8060 triple-quadrupole mass spectrometer. Run time is 38 minutes. Hands-on labor is a minute or two for sample prep.
SFC columns
Nacalai USA
Nacalai USA recognized the need for more selective phases in SFC and extended its Cosmosil Cholester line to include quinoline, 2-ethylpyridine, 3-hydroxyphenyl, and pentabromobenzyl. These surface chemistries are bonded to 2.5- or 5-μm silica particles.
Princeton Chromatography
Column selectivity is much more important in SFC than in HPLC: surface chemistry needs to be moderately polar. Thus, Princeton Chromatography (Cranbury, N.J.) introduced the PrincetonSFC 2-Ethylpyridine, PrincetonSFC PPU (propylpyridylurea), and PrincetonSFC Diol columns, which provide a range of selectivity. Column hardware ranges from analytical (~2 to 4.6 mm i.d.) to preparative (50 mm i.d.).
TLC-MS interface
Figure 6 – TLC-MS Interface 2. TLC plates are placed on the table, target spots are located and registered, the sampling head (center) is lowered onto the plate, and liquid is dispensed onto the plate and sucked up for transfer to the MS inlet. (Image courtesy of Camag.)Camag (Muttenz, Switzerland) displayed the TLC-MS Interface 2 (Figure 6) as an upgrade to previous interfaces. It consists of a scanner bed for the thin-layer chromatography (TLC) plate with an elution head that is lowered to the spot on the plate. Once in contact, a suitable solvent, often methanol, is pumped through the delivery orifice on the elution head onto the plate. The vacuum orifice is only 2 mm away, so the elution liquid with the analyte is sucked up and transferred to the inlet of the mass spectrometer. Because the spot is located with the cross-hairs of a precision laser, the elution head is accurately positioned over the centroid of the spot. Any residual silica from the plate is removed from the solvent output by a 2-μm filter.
Capillary electrophoresis instrument
Advanced Analytical Technologies, Inc. (Ankeny, Iowa) exhibited the FEMTO Pulse Automated Pulsed-Field CE Instrument for RNA and DNA assays, even from a single cell. The key is the programmed electric field that focuses the resolution of the wide separation range on a particular region. DNA as large as 165,000 base pairs can be separated in one hour; 200,000 bp requires two hours. The FEMTO Pulse can process 12 samples simultaneously. Pacific Biosciences (Menlo Park, Calif.) distributes the instrument under the name “Fragment Analyzer.”
Acoustophoresis
Another example that the capillary and nanoworld is much more than simply scaling down was given in a poster by Gayatri Gautam of the New Mexico Institute of Mining and Technology (Socorro). His poster introduced acoustophoresis in capillaries for the separation of particles, including cells. It operates by irradiating particles in a narrow planar capillary with ultrasonic sound. The particles have a resonance frequency, so they migrate to different regions depending on analyte density, compressibility, and size. For example, cells often change their density when treated with taxol. Another example showed the focusing effect on polystyrene particles. The first target is to separate normal and malaria-infected red blood cells as part of an assay for malaria.
Centrifuges
The Optima Analytical Ultracentrifuge (AUC) from Beckman Coulter (Indianapolis, Ind.) won a Bronze Pittcon Today Excellence Award. It has improved electronics so that data acquisition is five times faster than the previous model, the ProteomeLab XL-A/XL-1. Radial resolution is three times higher for a 15× improvement. The optical systems are located outside the rotor chamber, which improves maintenance. AUCs have helped characterize larger molecules, oligomers, and particles in polymer, life, and material sciences.
Distillation systems
Chemtech Services
Chemtech Services (Lockport, Ill.) introduced a laboratory unit for short-pathlength distillation. Unlike conventional batch distillations, the source liquid flows over the evaporator quickly, which reduces residence time in the hot zone to less than 1 minute. Operation is performed in a vacuum, further reducing the temperature required for vaporization. The units find application in the fractionation of natural products and oils, including cannabis.
GT Instruments
Designed for ASTM D2892 and D5236, the GT Instruments (Kemah, Texas) Potstill distillation model RTBP accommodates flasks ranging from 0.5 to 3 L. Fractions are collected automatically in up to eight receivers. Run time is less than 8 hours. The RTBP is designed for catalyst evaluation and small crude oil labs.
Sample preparation systems
Applied Separations
Applied Separations (Allentown, Penn.) introduced a new combination supercritical CO2/subcritical water extraction system in response to numerous requests for subcritical water (not to be confused with supercritical water) additions to the popular Helix modular SFE system. This was previously provided as an add-on, but is now included as a standard, integrated instrument system complete with upgraded heating and pressure, integrated software control, and improved safe subcritical water-extract collection. The subcritical water Helix system still has all the 10,000-psi supercritical CO2 (SCCO2) capabilities.
The company’s redesigned pressure-extraction vessels handle both SCCO2 and subcritical water. Note that the temperature at the end of the subcritical water extraction can be 150 °C to 180 °C—Applied Separations has engineered this issue to provide safe recovery of the extract.
CEM Corp.
The new Discover SP-D 80 microwave digestion system from CEM Corp. (Matthews, N.C.) facilitates digestion or extraction of 2-gram samples at temperatures up to 260 °C. This versatile technology, which takes advantage of the very wide solubility of polar and nonpolar analytes in superheated but very hot water, is useful for extracting target analytes from a variety of matrices, including pharmaceuticals, plastics, leachables, and environmental contaminants as per U.S. EPA Methods 3015, 3051, and 3052. Optional accessories include a 24-position sample rack. Even with this, the unit is small enough to fit in a fume hood.
Reproducibility of high-temperature extraction depends on the temperature inside the extraction vessel. Prior technology used fiber-optic probes to measure the extraction process. This worked, but was cumbersome since it involved loading a reference tube for comparison. The Mars 6 features iWave technology, which allows a contactless way to measure temperature inside the extraction tube. This can be added to existing CEM platforms.
The Oracle fat analyzer uses microwave dissolution combined with NMR.
Gerstel
Gerstel (Linthicum, Md.) featured the automated micro-scale chamber analysis sampling accessory for emission of semivolatile organic compounds using GC. These analytes are generally high-boiling-point finishing agents found in automobiles and enclosed rooms. The DHS L 3.5 measures emissions from 1-L samples of upholstery rather than relying on small punch disks or full-scale furniture.
TD 3.5 and 3.5+ extend the line of thermal desorption units for 3.5-inch thermal desorption tubes, which are specified in several reference methods. The 3.5-inch tubes typically contain 25% more sorbent than other designs. This improves capacity and capture efficiency.
Horizon Technology
Figure 7 – SPE-DEX 5000 Disk Extraction System for automated extraction of up to three samples according to standard protocols. (Image courtesy of Horizon Technology.)Horizon Technology (Salem, N.H.) introduced two new products. The SmartPrep Extractor II automates manual extraction workflows. The positive pressure design moves the liquids during the extraction process, which avoids problems of pumps losing their prime. This is important for pumping solvents such as methylene chloride. Like its predecessor, the Extractor I, it is designed for the reliable, reproducible extraction of difficult analytes such as perhalogenated compounds, nitrosamines, aflatoxins in food, and furans in transformer oils.
The SPE-DEX 5000 Disk Extraction System extracts analytes with filter disks. Capacity is lower than the beds used in the Extractor II, but some methods specify large-volume samples. The 5000 has three parallel and independent channels that automate the entire workflow (Figure 7). Liquid sample (20 mL to 2 L) is loaded and filtered quickly; then the disk is eluted.
Polymer Char
Carbon black is used as filler in some polymers such as polyethylene. Pigments and catalyst residues are also found. All can be problematic in GPC of olefins, clogging filters, columns, and transfer lines, and producing noise spikes in light-scattering detectors. However, carbon black is notoriously difficult to remove. To solve this problem, Polymer Char (Valencia, Spain) developed the EFS (external filtration system) to filter the sample prior to analysis. The sample is placed in a 10- or 20-mL vial, and the shaking level and temperature range are set. Next, the receiver vial and filtration cartridge are loaded. In 2 minutes, the dissolved sample is clear and particulate-free, with no intersample contamination.
Restek
While SPME is a very popular sampling technology, scientists at Restek noted that durability and convenience could be improved if the tip of the SPME fiber had a longer-lasting, sharp point. They selected industrial diamonds for the tip, which they call Arrow. The diamond tips are very long-lasting and protect the fiber coating. Thus, fiber thickness is increased, which greatly boosts capacity. An improved analyte response is typically seen, which can be traded for a shorter extraction time.
SiliCycle
SiliCycle’s (Quebec, Canada) SilaPrep SPE tips facilitate solid-phase extraction in the femtomole to picomole range. Conventional SPE materials are mechanically embedded into the plastic tip without glue. The lack of binders improves sample integrity. SilaPrep tips are available with sample volumes of 0.5–10 μL, 2–25 μL, and 5–50 μL.
Credits and Pittcon 2018
Pittcon 2017 attracted about 14,150 conferees to Chicago’s McCormick Place. Visitors came from 89 countries; 28% were first-time attendees, and 787 firms participated in the exhibition, occupying 1404 booths.
Pittcon 2018 is scheduled for February 26 to March 1, 2018 in Orlando, Florida.
Robert L. Stevenson, Ph.D., is Editor Emeritus, American Laboratory/Labcompare; e-mail: [email protected].