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A 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)

Click the title above to open the LCGC North America February 2016 Application Notebook Issue, Vol 34 No s2, in an interactive PDF format.

Click the title above to open the LCGC North America February 2016 Chromatography and Sample Preparation Terminology Guide, Vol 34 No s2, in an interactive PDF format.

The winner’s of LCGC’s 9th annual awards are highlighted

Recently several states have legalized recreational and medical marijuana. This has created a confusing set of circumstances due to legalization at the state level, but cannabis is still an illegal schedule 1 drug at the federal level. This confusion also affects the development of analytical methods because there are no clear guidelines available to laboratories. This whitepaper will discuss the following topics: • Overview of state analytical requirements • Discussion of analytical method development for cannabinoids and related compounds of interest • Discussion of method performance

UV technologies are being increasingly used in water purification systems, taking advantage of the germicidal properties of UV and also its effect in reducing organic contaminants. This paper discusses the effectiveness of using UV technologies along a water purification chain and the parameters and configurations to be considered when selecting UV lamps for water purification systems.

Volatile organic compounds (VOCs) are carbon containing compounds that evaporate easily at normal temperatures. They are typically generated from petroleum products, plastics, paints and solvents,. Other sources are the disinfecting agents used to control microbial contaminants in drinking water. Disinfecting agents react with naturally occurring organic matter in the source water to produce VOCs known as trihalomethanes. When VOCs are spilled or improperly disposed of a portion will evaporate, but some will soak into the ground and eventually end up in drinking water supplies

Ion chromatography (IC) has been recognized as one of the most competitive techniques for trace analysis, based on results from continuing research and development work into different types of instrumentation. Ultratrace analysis requires the use of extremely clean reagents, including water. The ionic content of water was monitored by IC along a water purification chain, from tap water to ultrapure water. This study shows that ultrapure water from a Milli-Q system is suitable for trace analysis by IC.

Semivolatile calibrations on this column dimension often range from 1.0 to over 100 ng/µL; however, a 0.25 mm ID column usually experiences peak overload as the mass on column approaches 10 ng. As shown in Figure 1, isobars that elute close together-such as benzo[b]fluoranthene and benzo[k]fluoranthene-quickly become unquantifiable as mass on column increases. Under split conditions, the resolution requirement (50% valley) is met for all nine calibration standards, and the peak apices shift less than 0.04 min, indicating only minor peak overload. Conversely, under splitless conditions, the three highest concentration calibration standards fail the resolution criterion. The peak fronting and resulting overlap from column overload make it impossible to generate a linear calibration including these points. Additionally, the peak apex of benzo[b]fluoranthene shifts more than 0.2 min, which could result in an erroneous compound identification.

Pavel Jandera spoke to Frantisek Foret about building his own liquid chromatograph, the birth of “modern” high performance liquid chromatography (HPLC), the importance of exploring (and understanding) earlier research papers, current trends in contemporary chromatography, and his inspiring advice for aspiring chromatographers.

Fluorinated stationary phases, especially those including a pentafluorophenyl (PFP) moiety, have become popular alternatives to the more traditional alkyl (C8 and C18) phases. Many modern column lines have, in fact, been initially introduced with the standard C18 and a PFP phase because of their orthogonality. In this instalment, the differences between alkyl phases and PFP phases are discussed in terms of fundamental interactions. The origin of the interactions is also interpreted to better understand how analysts can use and control them to develop effective and rugged analytical methods.

An excerpt from LCGC’s e-learning tutorial on sample preparation troubleshooting at CHROMacademy.com

Click the title above to open the LCGC Europe February 2016 regular issue, Vol 29, No 2, in an interactive PDF format.

Click the title above to open the LCGC North America February 2016 regular issue, Vol 34 No 2, in an interactive PDF format.

Ultrahigh-pressure size-exclusion chromatography (UHPSEC) can potentially offer a new direction and overcome some of the disadvantages (for example, limited resolution and long analysis time) associated with conventional SEC analysis. UHPSEC is based on using sub-3-µm silica-organic hybrid particles under elevated pressures (often above 400 bar) to improve the separation efficiency and increase analysis speed. In spite of the benefits promised by the chromatographic theory, there are some uncertainties that may limit the proliferation of UHPSEC in polymer analysis. As a result of possible issues associated with the use of a different stationary phase - including secondary interactions and polymer degradation - it is unclear whether UHPSEC will provide results comparable to those of traditional SEC methods. In this article, the advantages and challenges of UHPSEC for the analysis of different engineering thermoplastics are discussed, as well as a comparison of results obtained with UHPSEC and conventional SEC.

A glimpse of what’s on offer for chromatographers at Pittcon 2016, which will be held from 6–10 March 2016 at the Georgia World Congress Center in Atlanta, Georgia, USA.

This is the third “LC Troubleshooting” column in a series related to problems that we associate with liquid chromatography (LC) columns. This month is the first of several discussions looking at problems that are caused by chemical problems with the column.

Mark Schure spoke to LCGC Europe’s Lifetime Achievement Award winner, Hernan Cortes, about his career with Dow Chemical, multidimensional chromatography, the evolution of mass spectrometry (MS), and the direction that liquid chromatography (LC) is taking.

Thermal desorption sampling often provides a means for bringing otherwise intractable samples to a gas chromatography (GC) column for separation and detection. In this instalment, John Hinshaw describes the principles of thermal desorption sampling in relationship to other analysis techniques for volatile solutes.

Cloud-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.

The silica-based packing in reversed-phase columns is not inert. Here we consider what happens when the mobile-phase pH is too high or too low.

Data integrity issues are changing the way that we should be undertaking computerized system validation (CSV) of our chromatography data systems (CDSs). Do you understand what is required in the brave new world of CSV?

The selectivity of different combinations of organic modifiers, pH, and types of reversed-phase liquid chromatography (LC) materials has been characterized using Tanaka column characterization, linear solvent energy relationships (LSER), and selectivity correlations. The three characterization techniques highlighted the potential complementary selectivity of these phases and conditions as well as the type and dominancy of some of the retention mechanisms involved. Subsequently, selectivity differences were proven to be valid in the practical separation of acids, bases, and neutral analytes. This paper aims to assist chromatographers in producing highly efficiency method development strategies for reversed-phase LC separations in a relatively short time frame.

Since their beginnings in 1986, UCT has evolved into a major competitor in the field of silica based solid phase extraction technology. The first to pioneer commercially available ‘mixed-mode’ SPE products, 30 years later UCT is still optimizing sample analysis for forensic, pharmaceutical, clinical, environmental and agricultural laboratories. Michael J. Telepchak, founder and CEO UCT, Inc., has laid the foundation for this powerful technology and has truly served as a catalyst for its transformation from a novel technique to an industry gold standard. From fundamental chemistry to manufacturing and business development, he has bared witness to all facets of the evolution of solid phase extraction and will speak on the monumental impact it has made on the scientific community.

Since their beginnings in 1986, UCT has evolved into a major competitor in the field of silica based solid phase extraction technology. The first to pioneer commercially available ‘mixed-mode’ SPE products, 30 years later UCT is still optimizing sample analysis for forensic, pharmaceutical, clinical, environmental and agricultural laboratories. Michael J. Telepchak, founder and CEO UCT, Inc., has laid the foundation for this powerful technology and has truly served as a catalyst for its transformation from a novel technique to an industry gold standard. From fundamental chemistry to manufacturing and business development, he has bared witness to all facets of the evolution of solid phase extraction and will speak on the monumental impact it has made on the scientific community.

A 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).

Some modern HPLC systems resemble spacecraft in terms of their technology, designed as they are to operate to the highest efficiencies, compared to traditional systems.

A fully tested LC-MS/MS workflow for rapid and robust quantification of more than 250 pesticides below maximum residue limits (MRLs) with sensitivity, accuracy, and precision that meets stringent EU guidelines.