Editor’s Page
Review of HPLC 2014: Advances in HPLC and So Much More—Part 2
by Robert L. Stevenson
art 1 of this meeting review of HPLC 2014 (May 11–15, New Orleans, LA) appeared in the August issue (http://www.
americanlaboratory.com/163469-Review-of-HPLC-2014-Advances- in-HPLC-and-So-Much-More/). Topics included the current state of LC, ultrahigh-performance liquid chromatography (UPLC), column packing technology, and flash chromatography. Part 2 will start with an overview of column lines, and conclude with my impressions of the decade in sepa- ration technology.
P
Columns and column packings HPLC columns are a well-served market with an amazing 47-year history
of continuous innovation and development. Interest is always high. Why? Columns give chemists an opportunity to discuss chemistry. After all, we spent years in school studying books of descriptive material. It’s not surprising that we like to show that all the work has present value.
Column product lines
/g for larger molecules, and shorter retention times. Surface chemistries include C18, C8, and silica. The AichromBond AQ is designed for separation of moderately hydrophilic compounds. For even more polar analytes, a HILIC phase is also available. The AichromBond SB series is designed for chromatography at low pH, even as low as pH 1.0. The alkyl side chains shield the silica surface from the analyte, which reduces silanol interference. SAX and SCX ion exchangers round out the product line.
Flare columns
Diamonds are nearly nondestructible, so it is not surprising that Flare columns from Diamond Analytics (Orem, UT) are rated from pH 1–13 and 100 °C. Flare columns are 3.6-μm particles that provide about 100,000 plates/m chromatographic efficiency. The phase starts off with a carbon core that is coated with a thin layer of polyamine followed by a thin layer of nanodiamonds. This cycle is repeated layer by layer until the proper
AichromBond columns Aichrom HPLC columns from Abel Industries (Vancouver, Canada) were expanded from the AichromBond XB-1 series, which includes C18, C8, phenyl, CN, NH2, and bare silica with a dp of either 3 or 5 μm. The silica is rated for use in basic eluents up to pH 10. AichromBond X-2 has a lower surface area, 200 m2
particle size is reached. Then, the entire composite is locked in place with a diperoxide crosslinker. Finally, the surface chemistry such as C18 is covalently attached. Phases include Flare C18+; C18 MM (for mixed C18 and weak anion exchange); and Flare HILIC, which features an amino– diol surface chemistry.
SpeedCore HPLC columns Fortis™ Technologies (Cheshire, U.K.) is the latest firm to jump on the core-shell bandwagon with introduction of the SpeedCore HPLC column line. Speed core starts with a 1.8-μm solid silica core encased in a 0.4- μm silica shell with 80-Å micro pores. Surface chemistries include C18, diphenyl, PFP (pentafluorophenyl), and HILIC. Packings for RPLC are end- capped. The columns are stable from pH 2 to 9. The principal advantage is that column efficiency declines very slowly as the flow rate increases. This favors running the column at very high linear velocity to save time.
PRP™ columns Hamilton (Reno, NV) continues to expand the PRP column line with introduction of the PRP-C-18. The C18 surface chemistry is bonded to cross-linked polystyrene, divinylbenzene copolymer beads that are much more stable toward strong acid or base and temperature (up to 100 °C) than corresponding silica. The particle size is 5 μm. Pmax
is 5000 psi.
Kromosil UHPLC columns AkzoNobel’s (Amsterdam) Kromosil UHPLC columns start with 1.8-μm- diam spherical silica with 100-Å pore. C4, C8, and C18 surface chemistries are bonded to the particles before packing into 2.1 × 50 or 100-mm columns. Thus, AkzoNobel’s product line of columns now includes 1.8-, 2.5-, 3.5-, and 5-μm-diam packings. Kromosil is respected for providing silica-based column packings with exceptional stability to extremes in pH. With the range of particle sizes, one can select the optimum particle size to fit the constraints of the method.
Titan and BIOshell™ columns In the Supelco (Bellefonte, PA) booth, I found two new column lines for LC. Titan columns start with a 1.9-μm totally porous silica that has been produced by the Ecoporous™ manufacturing process. Test chromato- grams for 2.1-, 3.0-, and 4.6-mm-i.d. columns (all 5 cm long) show that efficiency increases significantly with column diameter, up to 306,000 plates per meter. Initially, the surface chemistry is endcapped C18. In
AMERICAN LABORATORY • 4 • SEPTEMBER 2014
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