Advances in Separation Science Technology and Applications at Pittcon 2015

After 50 years of uninterrupted growth, separation science, while showing signs of maturity, is still enabling significant advances in environmental research, in the so-called “’omics” sector and in health care. This review will focus on new instruments and accessories exhibited at Pittcon for analytical and laboratory-scale preparative chromatography.

Ion chromatography

Thermo Fisher Dionex

Dr. Yan Liu of Thermo Fisher Dionex (Sunnyvale, Calif.) introduced the Dionex EGC 500 K2CO3 cartridge and Dionex EPM 500 modifier for high-pressure eluent generation, which is rated for column pressure up to 5000 psi. This is compatible with columns packed with 4-μm-diameter ion exchangers.

Nichiri Kogyo K.K.

Nichiri Kogyo K.K. (Chiba, Japan) introduced two new detectors. The iCM8401 for nonsuppressed ion chromatography has the following specifications: noise, 0.95 nS/cm; drift, 1.5 nS/hr; cell volume, 0.1 μL; limit of detection at signal-to-noise (S/N) = 10, 0.25 ppb Clˉ. This is about a tenfold improvement over the previous model (iCM8301). The detector has a smartphone dock and communication capability.

The iCM2M 8401 is a novel, contactless conductivity detector for capillary LC and electrophoresis. Two low-volume detector cells are available (0.2 μL and 0.8 μL). Both use a barrier electrode mounted between the working electrode and the counter electrode. This reduces extracellular capacitance coupling, decreasing noise by half or more. The cell is rated to 725 psi, which should be more than sufficient to prevent bubble formation. Both detectors are distributed in North America by JM Science (Grand Island, N.Y.).

Liquid chromatography

Cole-Parmer

Cole-Parmer’s (Vernon Hills, Ill.) LC2 system is an integrated binary gradient HPLC with a fixed-wavelength detector (254 nm). Two flow rate options are available (0.001 to 5 mL/min and 0.01 to 10 mL/min), depending on the pump head. The standard flow path is stainless steel, but PEEK is an option. Pump heads are self-flushing to extend seal life.

JASCO

JASCO (Easton, Md.) has revamped almost its entire product line with new systems for ultrahigh-performance liquid chromatography (UHPLC), Rapid Resolution HPLC, analytical SFC and preparative SFC. Flow rate and Pmax best differentiate the three new liquid chromatographs: conventional HPLC, 500 bar; rapid HPLC, 700 bar; and UHPLC, 1300 bar. The latter two modes require specific flow cells for low dispersion. For preparative work, three pump modules are also available: JASCO recommends the 20-mL/min pump for columns up to 21 mm i.d., the 50-mL/min pump for i.d.s up to 30 mm and the 120-mL/min version for column diameters up to 50 mm.

Detector options for the LC-4000 series include photodiode array, differential refractive index, circular dichroism, optical rotation, UV/VIS and fluorescence. The latter two can monitor two wavelengths simultaneously.

Malvern Instruments

Malvern Instruments (Malvern, U.K. and Westborough, Mass.) introduced the OMNISEC REVEAL system, which integrates a liquid chromatograph optimized for steric exclusion chromatography (SEC) with four detectors. The output of these detectors can be combined to provide a universal calibration curve for polymers. The detectors can be purchased individually, but when they are integrated as the OMNISEC REVEAL, peak dispersion from inter-detector transfer lines is reduced and temperature control is improved. Photodiode array, refractive index and light scattering detectors are offered. A new self-balancing viscometer completes the detector package. The data output from each detector is processed to provide a universal calibration curve relating elution volume to molecular structure of polymers.

PerkinElmer

PerkinElmer (PE, Waltham, Mass.) introduced the Altus HPLC and Altus UPLC systems. UPLC, a registered trademark of Waters Corp. (Milford, Mass.), has, until now, been applied only to the Waters’ ACQUITY UPLC line of instruments. The Altus UPLC is an OEM instrument built by Waters, and the Altus HPLC is based on the Waters Alliance product and built to PE’s specifications for use specifically in the environmental sector. Waters Empower 3 chromatography data software is used for instrument control and report generation.

Scientific Systems Inc.

Scientific Systems Inc. (SSI, State College, Penn.) updated several HPLC pumps. The MX Class is designed for isocratic separations with a single piston pump. Flow range is 10–40 mL/min with a Pmax of 5000 psi. The flow path is stainless steel, PEEK or titanium. A pulse damper is optional. The pump is offered for laboratory-scale preparative applications such as flash chromatography or gel filtration. SSI’s CP Class dual-piston LC metering pumps come in five flow and pressure ranges, including flow rates that are often required for pilot plant and process scaleup. PR Class piston pumps provide either 100 or 300 mL/min flow rates at Pmax of 40,000 and 1000 psi.

Shimadzu

The Prominence-I and Nexera-I HPLCs from Shimadzu Scientific Instruments (Columbia, Md.) use an interactive communication module (ICM) for improved communication via Shimadzu’s LabSolutions network. Information is available for real-time monitoring or results sharing within the extended laboratory. Remote operation in a hood or isolation cell is supported by the ICM. An automated injector is specifically designed for viscous samples. Samples can be held in vial racks or multiple-well plates. The ICM should facilitate communication of results and reduce turnaround time.

Teledyne Isco

CombiFlash EZ Prep is Teledyne Isco’s (Lincoln, Neb.) new combination flash and high-pressure preparative LC. Flash separations provide a quick way to eliminate unwanted products and starting materials from a synthesis cocktail. With two clicks, the system converts to preparative LC separation with high-resolution columns. Column load for the first flash stage is 10 mg to 33 g. The chemist can then convert to higher-resolution preparative LC using columns as large as 50 mm i.d., eluting at up to 200 mL/min to a Pmax of 3500 psi. Detection options include UV, evaporative light scattering detection (ELSD) and MS.

Thermo Fisher Scientific

Thermo Fisher Scientific (Waltham, Mass.) introduced the Vanquish UHPLC platform, which was accompanied by columns packed with 1.5-μm coreshell particles to highlight the 22,000-psi Pmax. The compact design looks like a single cabinet, but inside the door is a highly tooled pump, columns and an autosampler. An accessory sample hotel holds up to 20 384-well plates. The transfer of vial racks or multiple-well plates is automated.

FPLC

Four new fast protein liquid chromatography (FPLC) systems were introduced this year.

Knauer GmbH

Dr. Ing. Herbert of Knauer GmbH (Berlin, Germany) introduced the Contichrom preparative LC, which is designed for developing bioprocessing purification methods including simulated moving bed (SMB), batch and continuous multicolumn purification schemes. A key goal is upward scalability while maintaining yield, and product purity profile from the laboratory to the plant. Software provides intuitive control of the purification scheme, and the system is FDA 21 CFR Part 11 compliant.

The lab pump flow rate is 0.01 to 10 mL/min, while the prep pump provides flows of 1 to 100 mL/min. The UV detector operates at a wavelength range of 190 to 750 nm using a D2 lamp.

For routine purification in proteomics, the company introduced the AZURA Bio LC line of stackable, modular LCs, which feature a metal-free mobile phase flow path. Six mobile phase pumps, with Fmax of 10, 50, 100, 250, 500 and 1000 mL/min, offer a metal-free mobile phase flow path. Radiofrequency identification (RFID) chips identify the pump heads and the flow rate is set accordingly. Options include a fraction collector, autoinjector, autosampler, mobile phase selection, column switching single and multiwavelength UV, diode array, conductivity and pH.

Practichem

Practichem (Research Triangle Park, N.C.) introduced the Arista Slice, a compact liquid chromatograph with biocompatible liquid flow path and integrated fraction collector. The pump is rated at 25 mps, or 3525 psi. Detection is dual-wavelength UV absorbance and conductivity.

Thermo Fisher Scientific

The UltiMate 3000 BioRS system from Thermo Fisher Scientific extends the popular UltiMate line into the biocompatible segment. The wide flow-pressure range allows the system to support fast, high-resolution assays as well as laboratory-scale prep.

Significant applications of LC

The GlycoWorks RapiFluor-MS N-glycan kit from Waters runs on an ACQUITY UPLC H-Class equipped with a fluorescence and QDa MS detector. Glycans are usually conjugated to proteins as part of the post-translational modification, which activates the protein. N-linked glycans also play an important role in cell–cell interactions. For example, tumor cells make N-linked glycans that are abnormal. These are recognized by the CD337 receptor on natural killer cells as a sign that the cell in question is cancerous. Glycans are common modification reagents. They can be bound to the protein either by oxygen (O-linked) or nitrogen (N-linked). Until now, N-linked glycans were more difficult to cleave and detect.

Update on acetonitrile

In early 2008, chromatographers worried about the declining availability of acetonitrile. Part of the problem was loss of production in the U.S., Europe and China. Now, Concord Technology (Tianjin) Co. Ltd. (Tianjin, PRC) offers acetonitrile in two grades. HPLC gradient grade has a UV cutoff of about 190 nm and featureless baseline in gradient blank runs. The lower-priced HPLC grade also has a low UV cutoff, but one may see some minor features in blank gradient runs. ACB SciTech, Inc. (Diamond Bar, Calif.) is the U.S. distributor.

Columns for LC

Advanced Chromatography Technologies

All too often MS instruments suffer from contamination by column bleed. Advanced Chromatography Technologies Ltd. (ACE, Aberdeen, Scotland) addressed the problem with encapsulated bonding technology (EBT), which increases C18 coverage. High surface coverage protects the silica from hydrolysis. This was illustrated with a featureless baseline on a gradient run from 5% to 100% acetonitrile. ACE also presented data showing that the new MS column has high chromatographic efficiency and low peak tailing. The high coverage provided by EBT helps extend the pH operating range to 1.5 to 11.0, which facilitates pH gradients. ACE columns are distributed in the U.S. by Mac-Mod Analytical Inc. (Chadds Ford, Penn.).

Advanced Materials Technology

Advanced Materials Technology (Wilmington, Del.) extended the applications-optimized line of HALO columns to HALO Glycan, which features a 90-Å pore. This joins the line of HALO Peptide (160-Å pore) and HALO Protein (400-Å pore). HALO Glycan’s surface chemistry is a highly polar entity with five hydroxyl groups bonded to 2.7-μm core-shell silica particles via a proprietary surface chemistry. This facilitates separations under hydrophilic interaction liquid chromatography (HILIC) conditions. Each column is tested with a glycan ladder to ensure efficiency and selectivity. Halo columns are distributed by MacMod.

AkzoNobel

AkzoNobel (Brewster, N.Y.) introduced Kromasil SFC, a new line of columns packed with 2.5-μm-diam silica that is optimized for SFC. Surface chemistry includes silica, 2-ethylpyridine, diol and cyano. These columns provide different chromatographic selectivity, including occasional reversals of elution order. The company also highlighted new Kromasil Eternity XT columns, which are packed with 1.8-μm-diameter silica. The particle size range of Eternity column packing now scales from 1.8 to 10 μm diameter.

ES Industries

Responding to the frustration of many mass spectroscopists running UHPLC-MS instruments, ES Industries (West Berlin, N.J.) exhibited a kit of three columns packed with different 1.8-μm stationary phases to help scout for useful selectivity in the UHPLC columns. Generally, the kit is used when results from C18 are not satisfactory. The Prevident-RP (1) LC/ MS column kit includes Epic PFP-LB (low bleed, pentafluorophenyl), Epic phenyl-SD (super dense) and Epic Polar, which has ether groups buried among the reversed-phase groups.

While the new Epic Biphenyl sub-2 is not in the kit, the company reports that the dense stationary phase coverage provides very different chromatographic selectivity compared to octadecylsilane (ODS) and PFP. Analytes with polarizable electrons (halogens, aromatics and nitrates), in particular, are strongly retained.

GL Sciences

Monolithic LC columns offer superior efficiency, peak counts and lifetime compared to traditional HPLC columns packed with particles. GL Sciences (Tokyo, Japan) presented a case in point with the introduction of MonoCap high-resolution 2000-mm fused-silica capillary columns for proteins and peptides. In one example, an LC-MS (Orbitrap XL, Thermo Fisher Scientific) separation of a THP-1 cell lysate showed an average of 2087 peptides with the monolith, compared to only 680 from the packed column. Run time was 10 hours. GL Sciences also introduced the MonoCap HILIC-UP for the assay of hydrophilic peptides and proteins. Both the C18 and HILIC MonoCaps are 2000 mL long and 100 μm i.d. The stationary phase is a bi-modal silica monolith. A similar study found 4000 peptide peaks from the HILIC-UP capillary and 5500 from the C18. Combined, they identified a total of 6500 peptides. The capillaries are installed with nanoViper fittings from Thermo Fisher Scientific.

Hamilton

The PRP-C18 stationary phase from Hamilton Co. (Reno, Nev.) promises useful efficiency and extended column lifetime. If one needs to work at 80 °C for solubility, the PRP-C18 shows double the plate count compared to room temperature. This is precisely why Hamilton recommends the columns for separation of synthetic oligonucleotides. Oligos above 60 °C are much less prone to hybridize with contaminating failure sequences. Hybridization can lead to complex chromatograms and loss of target product.

Imtakt

Amino acid analysis by ion exchange chromatography dates back to 1958 with commercialization of amino acid analyzers. Run times were many hours. The early analyzers were the predecessors of modern liquid chromatographs with metering pumps. Detection involved reacting the amino acids with ninhydrin and detecting visible absorbance. Today, column and detection technology have improved greatly. Imtakt USA (Portland, Ore.) introduced the Intrada Amino Acid column (50 or 100 × 3 mm) packed with mixed RPLC and ion exchange surface chemistry. With MS detection, the standard 18 amino acids can be analyzed in just over 1 minute. Another example showed the separation of 55 amino acids in less than 10 minutes. No derivatization is required.

JM Science

JM Science (Grand Island, N.Y.) introduced a sonic reservoir monitoring system that fits into the cap of the mobile phase reservoirs and measures the liquid level ultrasonically. When the ultrasonic system detects a problem, it can trigger a short message to the chromatograph. The contactless design nearly eliminates the risk of contamination. For the waste container, a floating sensor is used. When it gets near the top, this also triggers an LED indicator, audible alarm and error signal to the instrument controller.

Nacalai Tesque

Last year, Nacalai Tesque, Inc. (Kyoto, Japan and San Diego, Calif.) introduced COSMOCORE 2.6 C18, which was packed with 2.6-μm coreshell particles with bonded C18 for RPLC work. This year COSMOCORE 2.6Cholester, also for RPLC, was added, but the cholesterol provides superior resolution of cis- and trans-isomers, particularly in natural products. The larger particle size means that the columns are more compatible with non-UHPLC instruments.

Phenomenex

Phenomenex (Torrance, Calif.) exhibited two extensions to its Kinetex family of core-shell HPLC/UHPLC columns. Kinetex F5 is a new PFP phase that overcomes the reproducibility and performance limitations of existing PFP and F5 columns. Kinetex EVO C18 is a core-shell phase that incorporates a patented organosilica grafting process that provides pH stability from 1 to 12. Both are available in column diameters from 2.1 to 50 mm.

PolyLC

PolyLC (Columbia, Md.) continued its custom of adding new columns to meet important niches in clinical diagnostics and proteomics. The new PolyCAT A (2 μm, 1000-Å pore) provides superior resolution of post-translational modification of histone compared to a similar wide-pore 3-μm column. The improved resolution cleans up the MS chromatogram for natural and isotopically labeled histone H3.

For high-speed screening of protein-binding drug candidates, PolyLC has developed a novel high-speed SEC column. Drug candidates are incubated with the protein target and passed through a short SEC column. If the binding is strong, the protein–drug complex elutes at the V0 of the SEC column. Unbound drug candidates elute later since they are smaller. The bound drugs are displaced from the protein polymer and quantitated with RPLC/MS. Throughput is faster than one combination per minute.

Separation Methods Technologies

Self-assembly of a monolayer (SAM) stationary phase bonding is a novel concept developed by Separation Methods Technologies (SMT, Newark, Del.) for giving high surface coverage of silica bonding. Generally, high coverage improves stability and often reduces tailing. SMT claims coverage of 99.99% of the silanols compared to about 50% for conventional bonding, before end-capping. SAM bonding is especially useful in prep since the columns are so robust and peaks shapes are ideal.

SiliCycle

Using the adage “likes dissolve likes,” SiliCycle (Quebec, Canada) included a PFP surface chemistry in its offering of HPLC columns. The selectivity of PFP is high for fluorine-containing analytes, but is also finding favor for useful general RPLC. Also, the firm added strong cation exchange column packing that is effective for separating basic water-soluble analytes, including metabolites. Particle size ranges from 3.0 to 10.0 μm and in packed columns with diameters ranging from 2.1 to 50 mm.

Supelco

Supelco (Bellefonte, Penn.) introduced Bioshell glycan columns for HILIC mode separations. The K+LC columns start with Supelco’s fusedcore silica particles (2.7 μm diameter) with 90-Å pore diameter.

Previously, Ascentis core-shell columns from Supelco were built on 2.7- or 5.0-diam particles. Both were compatible with conventional HPLC instruments. However, for the UHPLC set, core-shell particles generally offer greater efficiency than porous particles of the same particle size. To take advantage of this, Supelco extended the Ascentis range down to 2.0 μm, hence Ascentis Express 2.0 micron. The shell of the column has 90-Å micropores with a 120 m2/g surface area. The surface chemistries are C18 and F5, but this is expected to expand in the near future.

Tosoh Bioscience

Hydroxyapatite (HA) is a nontraditional chromatographic stationary phase in the sense that it is a naturally occurring product (present in bones and teeth), whereas most commercially available stationary phases are cross-linked polymers or other synthesized base materials. HA has an affinity for many proteins, usually in a nonspecific manner. Its selectivity is not predictable and often not similar to conventional RPLC, silica and ion exchange phases. In most instances, the elution can be controlled through modifications in mobile phase concentrations of phosphates, NaCl or a combination of the two. CaPure-HA is available in bulk for packing into low-pressure columns for preparative applications from the laboratory to the plant floor. (Tosoh America, Inc. is located in Grove City, Ohio.)

Thermo Fisher Scientific

Julia Baek of Thermo Fisher Scientific in Sunnyvale, Calif. lectured on three new columns optimized for hydrophobic interaction chromatography (HIC) of monoclonal antibody fragments. These columns are particularly significant since I’m not aware of any introductions of columns for HIC in the last five years. HIC separations of proteins often avoid problems with protein denaturation, which can be significant with RPLC. Plus, the majority of the drugs in the FDA approval pipeline include intact antibodies, fragments or conjugates with other drugs.

The new columns are MAbPac HIC-10, MAbPac HIC-20 and MAbPac HICButyl. HIC is carried up using a reverse salt gradient elution. At high salt, the activity of water is reduced, which causes proteins to precipitate. As the salt content decreases, more water is available for dissolving the protein. Since the mechanism is not ion exchange, selectivity is generally orthogonal to both cation and anion exchange.

HIC-10 and HIC-20 have a proprietary amide surface chemistry covering high-purity 5-μm silica particles with 1000-Å pore. HIC-Butyl has a butyl surface chemistry bonded to a 5-μm-diameter nonporous hydrophilic polymer. The nonporous particle reduces capacity to one-third of that found for the porous silica phases.

Baek presented several enticing chromatograms. One showed the separation of MAb variants and aggregates from the main peak. Another compared the Fc and Fab fragments obtained after papain digestion on the three columns. The butyl column reversed the elution order compared to HIC-10 and HIC-20. These columns should stimulate interest in the HIC mode.

VWR

A well-engineered mobile phase isolation system for HPLC was presented by VWR (Radnor, Penn.). The mobile phase bottletop for a GL45 bottle is replaced with a plastic one that includes an air valve that selectively passes air in as the mobile phase is consumed, while preventing backflow of the vapors from the mobile phase; it also catches dust. A small indicator signals when the air filter needs to be changed. Color-coded pass-through fittings facilitate inspection of correct plumbing.

Welch Materials

Welch Materials, Inc. (Jinhua City, PRC and Potomac, Md.) is a new entrant in North America’s market for GC and HPLC chromatographic columns. A 100-page catalog describes several series of columns, often cross-referenced to popular Western brands.

Twenty years ago, nearly all LC columns in China were packed with stationary phases imported from Western firms. Prices were high (above U.S. list), especially if the columns were packed in the West. This was an unsustainable situation.

YMC America

YMC America (Allentown, Penn.) extended the YMC-Triart ExRS column line to add a high-carbon load C18 with 25% carbon bonded to a hybrid organic/inorganic particle. The high load provides strong retention of hydrophobic analytes. High-carbon loads often confer unique selectivity on C18 surface chemistry, which is useful in separating positional isomers. The hybrid particle base is recognized for its stability at very low and high pH.

The company also introduced YMC-Meteoric Core C18 and C8 columns. Either ligand is bonded to 2.7-μm core-shell silica particles with 80-Å pore. The C18 stationary phase has only a 7% carbon load compared to 25% for the ExRS (above). YMC also has a special C18 bio packing with 5% carbon load but 160-Å pore.

The BioPro SmartSep Q/S from YMC has a mixture of quaternary ammonium anion exchange mixed with butylsulfate groups for cation exchange. The surface chemistry is designed for protein separations for intermediate and polishing stages. Capillary columns are favored in LC/MS and sample limited assays. To meet this need, YMC extended the MicroLC column line with four diameters (75, 100, 300 and 500 μm) and four lengths (50, 75, 100 and 150 mm). Thirty-two stationary phases and choices of pore diameter hydrophobicity, pH operating range and more are included.

Supercritical fluid chromatography

Applied Separations and ES Industries

Applied Separations (Allentown, Penn.) and ES Industries (West Berlin, N.J.) cooperated on the development of the eCO2Chrom for flash SFC using carbon dioxide/methanol as eluent. Samples are injected on the eCO2 as dry loads on silica or direct liquid injection onto a disposable column. Elution is with pressurized CO2, usually with a low percentage of methanol. The sample typically stays in the methanol as the CO2 evaporates from the vials in the built-in fraction collector. Since CO2 has low viscosity, one can use higher-resolution columns packed with smaller particles and still stay within the design pressure of the instrument. Fraction collection is based on a time window, or peak triggered by threshold or slope. The eCO2 is an integrated unit that has a small footprint. ES has developed a line of column packings specifically optimized for SFC.

JASCO

JASCO’s SFC-4000 series SFC covers the capillary to 3-cm-diameter columns. Five pumps cover the flow rate range from 0.1 to 120 mL/min. For narrow and microbore columns, the newly designed PU-4385 metering pump is designed for CO2 flow of 0.1 to 2 mL/min. For prep, the PU-4388 has an operating range of 10–120 mL/min. A co-solvent pump, the PU-4180, usually pumps methanol.

Reliable SFC requires cooling of the CO2 during the pumping cycle. The PU-4385 utilizes a solid-state Peltier cooler; PU-4386, 4387 and 4388 have a cooling jacket supported by an external circulating bath. The backpressure regulator is also an essential module. A variable stroke needle valve operates over the 1.0–50 MPa (7200 psi) range in steps of 0.1; adjustment precision is ±2%.

JASCO is noted for optical detectors. The CD/UV combination is used for on-line detection of chiral compounds after separation by chiral-SFC. The ratio of the CD and UV responses is called the g-factor, and is usually linear over the range of 0–100% of a potentially racemic mixture. This feature may be unique to JASCO.

Shimadzu

The big news was Shimadzu’s novel combination of SFE and SFC in one instrument, the Nexera UC (unified chromatography) system. Previously, interfacing these two techniques involved “tennis shoe” transfers of the sample. Plus, sample handling apparatus and quantities were seldom designed for compatibility.

Shimadzu started with a fresh design of an automated SFE instrument that involved putting milligram amounts of material in a sealed extraction vessel. This is placed in an automated sample hotel that stores 12 racks of six vessels. When the time is right, a rack is transferred to the SFE unit for processing. There, the sample is heated and extracted with CO2 under supercritical conditions. The extract passes to the injection port of the SFC, located immediately adjacent to the extraction module. The SFE loop is loaded, injected and eluted to the detector(s). A UV detector is the simplest choice, but Shimadzu’s staff recommends a top-of-the-line MS, especially for natural products, traditional Chinese medicines and trace pollutants such as pesticide residues. The instrument won the Editors’ Gold Award.

Gas chromatography

Several firms introduced GC/MS and GC×GC/MS instruments, but most mated an existing GC with a new MS.

Most gas chromatographs are set up and spend their life running the same assay day after day. They seldom push the envelope in terms of performance. Reliability is much more important.

For five decades, Gow-Mac Instrument Co. (Bethlehem, Penn.) has provided reliable, workhorse GCs. This year, the company introduced the 8100 series microprocessor-controlled GC, which is targeted for industrial laboratories, particularly for QA and QC. The human interface utilizes a high-contrast, high-resolution LCD and keypad. Two detectors can be mounted inside along with up to five columns. Temperature range is from ambient +5 °C to 450 °C. Cooldown from 350 °C takes 5 minutes.

Process GC

Pittcon 2015 was an ideal place to explore the status of the reshoring of the chemical industry that is developing as a result of America’s glut of natural gas and liquid petroleum. The first plants are scheduled to come on stream in 2015 and represent the initial phase of an estimated $200 billion investment. These plants will need GCs for process control and environmental compliance and product QC. Vendors report that activity is increasing smartly.

Orthodyne (Alleur, Belgium) showed the DID500/HE-ppb-ppm chromatograph, which uses a plasma detector to measure concentrations of Ne, H2, Ar, O2, N2, Kr, CH4, CO, CO2 and Xe in gas streams. Other process GCs focus on flame ionization detection (FID) or thermal conductivity detection (TCD), which has sensitivity in the high-ppb to percent range. Orthodyne has a library of purpose-built analyzers, each optimized for specific applications such as impurities in CO2 for carbonated beverages, and another for medical gases. Orthodyne is represented in the U.S. by COSA Xentaur Instrument Corp. in Yaphank, N.Y.

GC detectors

Shimadzu’s ECD-2010 Exceed Electron Capture Detector is designed to use proprietary Contact Free Technology to minimize fouling of the ECD source and collector from the analyte or matrix.

The Multi-Mode Plasma Detector (MMPD) for GC is a new detection option for GC from Analytical Flow Products (AFP, Thetford Mines, Quebec, Canada). The detector creates a soft plasma where the energy of the plasma is transferred to free electrons while the carrier gas remains cool. The stable discharge produces optical signals for detection in the emission or absorption modes in the IR or near-infrared (NIR) range, and fluorescence. By matching the optical filters to the analytes, responses can be group specific. The company recommends the MMPD as a replacement for TCDs and FIDs in GC. Supported applications include hydrocarbons +CO and CO2 without methanizer, mercaptans, BTEX and VOC; N2 in argon or helium; and ppb and ppm assay for moisture in gases.

GC/IR

Dani Instruments S.p.A.

The DiscovIR-GC from Dani Instruments S.p.A. (Colongo Monzese, Italy) deposits GC effluent onto an IR transparent rotating disc, which sorbs and transports the analyte to the IR beam. A few months ago, it was announced that Dani had acquired Spectra Analysis (Marlborough, Mass.). Over the decades, there have been several GC/IR combinations, but applications did not materialize and the technique went to the back burner. However, in the Dani booth, it was demonstrated that the DiscovIR-GC is often superior to MS for drug identification since the structure and signal of isomers is preserved. One application note showed that the number of synthetic cannabinoids of concern increased from two compounds in 2009 to 14 in 2010. Five of these made Schedule 1 on the Controlled Substances list.

Prism Analytical Technologies

Prism Analytical Technologies (Mt. Pleasant, Mich.) introduced MAX, The Absolute Standard, which is a gas chromatograph optimized for the assay of permanent gases with FTIR. The eluted gases pass into a multipass absorbance cell to increase detection sensitivity. Data processing algorithms use spectral time averaging to further improve S/N for ppt detection limit. As with MS, the infrared spectrum of analytes is information rich, so dynamic range is an incredible 10 logs. Chromatography does not affect quantitation.

GC software

Bruker (Billerica, Mass.) president Frank Laukien described PACER 2.0 software, which is designed for quick exception-based review of triple-quadrupole MS on GC or HPLC. The software looks for exceptions in a batch of similar samples such as pesticides. When unusual events are noticed anywhere in the peak-to-paper workflow, flags notify the operator. The PACER 2.0 workflow simplifies and accelerates the process.

GC headspace analysis

Headspace analysis by GC can involve thermal cycling of syringes from room temperature to over 110 °C. This challenges conventional PTFE plunger seals. Hamilton introduced a new spring-in plunger tip that greatly improves the seal integrity of the syringe plunger and barrel. CTC CombiPAL autosampler headspace syringes are particularly recommended for in-tube extraction (ITEX) assays using CTC CombiPAL autosamplers. Volumes offered include 1.0, 2.5 and 5.0 mL.

VOC monitoring

The U.S. EPA is getting serious about perimeter monitoring of hydrocarbon processing plants for VOCs. Benzene is the primary target analyte. By mid-2015, locations will need to comply with CFR 40 Part 63 Annex A, which requires two-week sampling into sorbent tubes, followed by thermal desorption in a GC/MS. Markes International Ltd. (Llantrisant, U.K. and Cincinnati, Ohio) introduced a series of products for Method 325 compliance, including a layout of the sampling points, sampling tubes, sampling tube conditioner, sampling apparatus and TD-100 automated thermal desorber. The laboratory needs to select a GC/MS, but Markes has designed sample processing and control interfaces for most of the common chromatographs.

Method 325 requires that sampling tubes remain capped after sampling. Markes DiffLoc caps fit on both ends of the sampling tube before the tube is placed in the desorber. The tube remains sealed until the carrier gas is applied, which sweeps the VOCs onto the column for assay.

Valves and tubing for GC

Analytical Flow Products introduced valves and actuators designed for GC. The new MRV mini rotary valve is designed after AFP’s purged rotary valves with 4-, 6- or 10-port design, with optional internal sample loop. Materials of construction include 316 stainless steel and Hastelloy C-22. Seals include PEEK, polyimide and polyphenylene sulfide (PPS). Pmax is 400 psi. AFP also introduced the VMOV modular valve oven for GC.

Precut metal tubing for GC and HPLC is made of SS-316L, Hastelloy C-22 or Monel 400. Outer diameters are 1/32, 1/16 and 1/8 in. Internal diameter can be as small as 0.005 in. The tubes have square ends, which facilitates making low-dispersion connections, and they are passivized after fabrication. Inner sufaces can be bare or coated with various materials.

Thin layer chromatography

For five decades, Camag (Muttenz, Switzerland and Wilmington, N.C.) has promoted thin layer chromatography (TLC) in the face of the explosion of HPLC and, more recently, UHPLC. Yet TLC is used daily by organic chemists and a range of analysts in the less developed world. After all, TLC works. This year, Camag featured visionCATS, a second-generation software platform optimized for TLC. The software’s new graphical user interface supports a client/server system that provides flexibility in integrating data from a wide range of analytical instruments. The key resource is a large database that facilitates retrieval of all data associated with a particular sample. Qualitative and quantitative results are provided for components of any encountered sample.

Centrifuges

Centrifuges are on the perimeter of separation science, so what could be new? On the Pittcon exhibit floor was a centrifuge equipped with dynamic rotor balancing. Conferees were allowed to challenge the unit, effectively putting the rotor out of balance by removing tubes and then starting a spin. Initial vibration quickly stopped. The unit featuring this capability is a benchtop centrifuge that operates at 13,000 rpm, generating 19,839 × g and manufactured by Hanlab of Chungcheongbuk-do, Korea.

Conclusion

For several decades, Pittcon was viewed by many as the world’s largest separation science meeting and exhibition. However, during the last decade, the focus has shifted from chromatography to spectroscopy, including imaging. Advances in mass spectrometry, including spectacular advances in imaging, are competing for attention.

I hope to see you in Atlanta for Pittcon 2016, and am already anticipating the range of technological advancements that will be an important part of the conference. For more information, please visit www.pittcon.org.

Robert L. Stevenson, Ph.D., is Editor Emeritus, American Laboratory/Labcompare; e-mail: [email protected].