The Effect of Microwave and Electron-Beam Treatments on Food and Packaging
January 20th 2016A team of researchers based in France has examined the consequences of microwave and electron-beam treatments on food and its packaging using high performance liquid chromatography (HPLC) and gas chromatography (GC).
Ion Exchange Sorbents for Metals Extraction- Analysis & Sorbent Use Selection Guide
January 19th 2016The use of ion-exchange sorbents for the preconcentration, separation and determination of metal ions is well established in the literature. Selection of an appropriate sorbent ensures both high efficiency in metal chelating while minimizing the mass of sorbent required for a particular analytical task. A high efficiency sorbent means that a smaller bed mass may be used thereby reducing the quantity of solvent required for elution yielding greater analytical sensitivity.
Pattern Modulation Offers Alternative to Pulse Modulation in GC×GC
January 19th 2016New research into flow modulation methods in valve-based two-dimensional gas chromatography (GC×GC) has produced an effective alternative to traditional pulse modulation.1 Described as “pattern modulation”, this new method increases effluent to the secondary column with flow rates compatible with most chromatographs and spectrometers.
Extending the Detection Limits for the Analysis of Organotin Contaminants Using Soft Ionization
January 19th 2016The inherent sensitivity and selectivity of time-of-flight mass spectrometry (TOF-MS) can be augmented by soft electron ionization (EI) to provide ultratrace-level quantitation of organotins in complex environmental extracts. These organotin species are a focus of current concern as environmental contaminants, but analysis using conventional 70 eV ionization energies is made difficult by their propensity to undergo extensive fragmentation. The use of soft EI helps to solve this problem by producing simplified spectra with enhanced diagnostic ions.
The LCGC Blog: Column Overload in Gas Chromatography with Vacuum Ultraviolet Detection
January 19th 2016Column overload is a very commonly encountered issue in gas chromatography (GC) for beginners. Changes in peak symmetry, generally observed as peak fronting, can be subtle in the sharp peaks generated by GC, but the result can be significant shifts in retention times, loss of resolution, and error in peak integration. LCGC Blogger Kevin Schug explains more.
An Italian Sabbatical to Bring 2D Chromatography to Texas
January 13th 2016After 10 years at U.T. Arlington, I have decided it is time to take one of the best opportunities afforded to researchers in an academic faculty position-to travel abroad and assimilate new techniques into my repertoire to enhance future research activities.
Scaled Down EPA Methods 8270 and 625: Solid Phase Extraction of 100 mL Samples or Less
January 8th 2016The EPA has updated methods 8270 (8270E) and 625 (625.1) to both now permit the use of solid phase extraction (SPE) to analyze for semi-volatile organic compounds (SVOCs) in aqueous samples and TCLP leachates. As a result of new advancements in instrumental sensitivity, smaller sample sizes can now be utilized to obtain required method detection limits, reducing solvent and standard consumptions and overall sample preparation time. This application note describes a reliable, efficient, and cost-effective SPE method utilizing two stacked cartridges for the extraction of 100 mL water samples or less.
Surfactant-Mediated Extractions, Part I: Cloud-Point Extraction
January 1st 2016Cloud-point extraction (CPE) manipulates temperature and surfactant concentration to move aqueous solutes into a micelle phase for separation. Although CPE has been around for some time, it is still considered an emerging technique. Much of the development, and most applications, of CPE have dealt with extraction and preconcentration of inorganic solutes. More recently, attention has turned to the use of CPE in the isolation of organic solutes. This month, we review how CPE works and focus on applications for extracting organics.
In Defense of Nitrogen as a Carrier for Capillary GC
December 14th 2015There has been much written about the use of nitrogen as a carrier gas for capillary GC. Formerly, to say it wasn’t any good. Latterly to say that it’s pretty good and a better alternative to Helium than hydrogen from a practicality standpoint.