The Effect of Microwave and Electron Beam Treatments on Food and Packaging
February 7th 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)
The Cannabis Analytical Conundrum
February 1st 2016Recently 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
The R&D Notebook for UV Technologies for Water purification
February 1st 2016UV 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.
Water for GCMS Analysis of Volatile Organic Compounds
February 1st 2016Volatile 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
Semivolatiles Analysis Using Split Injection
February 1st 2016Semivolatile 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.
AFFF-MALS-RI for Determining the Mass and Size Distributions of Amylose and Amylopectins in Starch
February 1st 2016Integration of RI peak areas enabled calculation of the AMY:AMP ratios, in excellent agreement with the nominal values. The values for Mw and Rz fall within the generally accepted limits found in the literature. Conformational plots for the AMP component verify its branched nature.
Mechanisms of Interaction Responsible for Alternative Selectivity of Fluorinated Stationary Phases
February 1st 2016Fluorinated 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.
Ultrahigh-Pressure Size-Exclusion Separations of Engineering Plastics: Challenges and Opportunities
January 31st 2016Ultrahigh-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.
Detective Work, Part 3: Strong Retention and Chemical Problems with the Column
January 31st 2016This 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.
Surfactant-Mediated Extractions, Part 1: Cloud-Point Extraction
January 31st 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.
Maximization of Selectivity in Reversed-Phase Liquid Chromatographic Method Development Strategies
January 30th 2016The 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.
UCT A 30 Year Tradition of Excellence in Sample Preparation
January 29th 2016Since 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.
UCT: A 30 Year Tradition of Excellence in Sample Preparation
January 29th 2016Since 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.