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With many new biopharmaceuticals now being developed, robust analytical methods are needed to ensure that these protein-based drugs are of high purity and safe with a minimum amount of side effects. Size-exclusion chromatography (SEC) is an important technique for investigating purity and is useful to identify and monitor protein aggregation, which can have economic and immunogenicity effects. This article discusses those column p; for SEC separations. [ABSTRACT FROM AUTHOR]

In his final "Column Watch" instalment, Ron Majors looks into his crystal ball and discusses future needs in the areas of high performance liquid chromatography (HPLC) and ultrahigh-pressure liquid chromatography (UHPLC) column technology and related instrumentation. He looks at where current technology may be heading and makes a prediction that monolith-based columns may still have a rightful place in the HPLC and UHPLC laboratory. This article concludes Majors' legendary tenure as a monthly columnist for LCGC. [ABSTRACT FROM AUTHOR]

The 42nd International Symposium of High Performance Liquid Phase Separations and Related Techniques (HPLC 2015), chaired by Gerard Hopfgartner was held 21-25 June in Geneva, Switzerland. This instalment covers some of the highlights observed at the symposium including stationary-phase developments, particle technology, and areas of growing application of HPLC. In addition, trends and perspectives on future developments in HPLC culled from the conference are presented. [ABSTRACT FROM AUTHOR]

There has been a revival of supercritical fluid chromatography (SFC) in recent years, especially in the chiral preparative field, but also more recently in the analytical area. However, SFC is considerably more complex than liquid chromatography (LC), mainly because of the compressibility of the mobile phase. One can say that SFC is a "rubber variant" of LC where everything considered constant in LC varies in SFC. In this review, we go through advances in theory, instrumentation, and novel applications. [ABSTRACT FROM AUTHOR]

The use of superficially porous particles (SPPs) in the manufacture of high performance liquid chromatography (HPLC) columns has become prominent in recent years. Over the course of the past decade most major manufacturers have built column lines around the technology. At the recent Pittcon conference in New Orleans, Louisiana, USA, a large number of oral and poster presentations centred on the current research and advances using superficially porous particles. This instalment aims to provide some highlights of these recent trends. [ABSTRACT FROM AUTHOR]

This is our annual review of new liquid chromatography (LC) columns and accessories introduced at Pittcon and throughout the previous year. This year, Michael Swartz, former author of our "Innovations in HPLC" and "Validation Viewpoint" columns, steps in as a guest columnist to write the review. [ABSTRACT FROM AUTHOR]

Hydrophilic-interaction chromatography (HILIC) is a complex system involving partition, polar, and ion-exchange interactions. Method development can be greatly facilitated by understanding the interactions that the different stationary phases provide and applying that knowledge to the separation task at hand. Through an understanding of the main differences of the set of analytes to be separated, a column or set of columns can be judiciously chosen to screen for effective retention and selectivity. [ABSTRACT FROM AUTHOR]

In this instalment of "Sample Prep Perspectives", we cover some of the basic scientific principles behind solid-phase extraction (SPE) to allow the correct mode of extraction to be selected through an understanding of how analytes interact with and are separated by the sorbent. We also look at some of the most common causes of low recovery in SPE and how they can be investigated and remedied. Finally, we examine some of the emerging technologies within the area. [ABSTRACT FROM AUTHOR]

Although it has been happening to some degree for centuries, food adulteration is increasingly becoming a worldwide epidemic, as evidenced by the melamine scandal of 2008 and recent meat and fish substitutions at major food chains. Analysts are applying more sophisticated chromatographic, spectroscopic, and enzymatic analytical techniques to monitor and measure food adulterants, which are often economically motivated. In this instalment, guest authors Jeff Hurst and Kendra Pfeifer from Hershey Foods explore high performance liquid chromatography (HPLC), ultrahigh-pressure liquid chromatography (UHPLC), and mass spectrometry (MS) approaches being adopted to keep ahead of the food adulteration game. [ABSTRACT FROM AUTHOR]

Many problems encountered executing high performance liquid chromatography (HPLC) methods are the result of decisions made during early method development. This instalment of "Column Watch" discusses a critical variable in method development: the choice of stationary-phase chemistry. We discuss two stationary phase classes, embedded polar group (EPG) and perfluorophenyl (PFP), that are highly complementary to alkyl phases from a fundamental molecular interaction point of view. An understanding of the contrasting interactions that these different classes of stationary phase chemistries provide then leads to more accurate decisions regarding what phases may be most appropriate for a given set of analytes. [ABSTRACT FROM AUTHOR]

In high performance liquid chromatography (HPLC) column development, the bonded-phase silica is often only investigated to determine the suitability of a packed column for a particular separation class and not much thought is given to optimization of the base silica to make the overall packing material more suitable for the assay. Here, we examine general-purpose standardized tests to determine the quality of bulk silica before and after bonding. Base silica features such as mechanical strength, acid and alkaline durability, loadability, and overload characteristics are a few of the parameters evaluated that have an impact on the final separation and purification characteristics for a difficult test analyte such as insulin. [ABSTRACT FROM AUTHOR]

HPLC 2014 was held 11-15 May in New Orleans, Louisiana, USA, for the first time and much earlier than normal. This instalment of "Column Watch" covers some of the technology and application advances presented at HPLC 2014. We review the overall liquid-phase chromatographic trends, summarize the awards presented, and discuss the column technology highlights observed at the symposium. [ABSTRACT FROM AUTHOR]

Sample preparation has often been viewed as the bottleneck in analytical procedures. Surveys have shown that time is typically the most frequent problem area for sample preparation procedures and that analysts can easily spend a majority of the total analysis time on sample preparation. While newly developed extraction techniques address time, modern chromatography advances are also moving towards faster separations. Based on these considerations, what is high-throughput sample preparation? Do modern extraction methods adequately address the issue of time? How can we address the analytical need for speed? [ABSTRACT FROM AUTHOR]

Part 2 of our yearly report on new products introduced at Pittcon. This instalment of "Column Watch" covers gas chromatography columns, supercritical fluid chromatography columns, and products for sample preparation, including small benchtop instruments. [ABSTRACT FROM AUTHOR]

Part 1 of our yearly report on new products introduced at Pittcon. This month, columns are highlighted, and high performance liquid chromatography (HPLC) and ultrahigh-pressure liquid chromatography (UHPLC) columns, packings, and related products are covered. [ABSTRACT FROM AUTHOR]

To achieve lower detection limits and better selectivity, researchers are always exploring new ways to enhance sample preparation and separation technology. The addition of electrical potential to existing technologies or for entirely new approaches is relatively unexplored but can create another dimension of selectivity in sample preparation. In addition, speed and sensitivity are added benefits. This instalment looks at the use of electroenhancement to solid-phase extraction, solid-phase microextraction, and membrane and liquid extraction. [ABSTRACT FROM AUTHOR]

New sorbent materials for solid-phase extraction (SPE), dispersive solid-phase extraction (dSPE), solid-phase microextraction (SPME), and other solid-liquid extraction methods continue to be developed both in academia and the commercial sector. Here, we cover some areas of significant development, including molecularly imprinted polymers (MIPs), dSPE for QuEChERS, nanomaterials, and mixed-mode and silicone monolith sorbents. [ABSTRACT FROM AUTHOR]

The article discusses the top 10 high performance liquid chromatography (HPLC) and ultrahigh-pressure liquid chromatography (UHPLC) column myths. It informs that UHPLC packed columns plug more easily than conventional HPLC columns. Reversal of an HPLC column to remove particulates is not possible. Liquid chromatographic separations are not affected by pressure.

Webster's New Collegiate Dictionary defines a myth as "an ill-founded belief held uncritically, especially by an interested group." Could that group be misinformed chromatographers? In the first of a two-part feature from Ron Majors, the top 10 high performance liquid chromatography (HPLC) column myths are presented and attempts are made to demystify them by offering some evidence that they are untrue. This part will feature myths 10 to six. Since ultrahigh-pressure liquid chromatography (UHPLC) has come about, new myths are popping up and these shall also be dealt with here. [ABSTRACT FROM AUTHOR]

The article discusses the 39th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2013) held in Amsterdam, Netherlands from June 16 to 20, 2013. The symposium highlighted the column technology advances and liquid chromatographic trends. Topics discussed included hydrophilic interaction liquid chromatography (HILIC), stationary phases and liquid chromatography (LC) -mass spectrometry. It featured awards presented to people for work in LC.

The article discusses the Pittcon 2013 Conference and Expo formally known as the 64th Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy that was held in Philadelphia, Pennsylvania from March 17 to 21, 2013. The expo featured several high-performance liquid chromatography columns including Accucore from Thermo Fisher Scientific Inc., Poroshell 120 from Agilent Technologies Inc. and Nucleoshell Phenylhexyl from Macherey-Nagel GmbH & Co.

The author discusses the usage of ionic liquids (ILs) and polymeric ionic liquids (PILs) in solid phase microextraction and dispersive liquid-liquid microextraction (DLLME) chromatographic methods. It highlights that the application of ILs and PILs in sample preparation for chromatography separation of sample results in faster separation of sample. It also highlights the properties of ILs and PILs which includes viscosity and vapour pressure which enhances resolution of samples.

The article reflects on different methods for extraction and determination of nonpolymeric compounds in synthetic polymers through chromatographic analysis. It highlights that liquid-solid extraction techniques is the most common methods for determination of additives, contaminants, and low molecular compounds present in synthetic polymers. It mentions that microwave assisted extraction, polymer dissolution methods, and gas chromatography are the polymer additive extraction methods utilized.

The article focuses on the concept of just enough sample preparation in the analytical cycle. It says that columnist Diane Turner presented the subject of how selectivity can be integrated in the sample analysis cycle in her column "It's All About Selectivity." It states that the concept relies on the increased sensitivity and selectivity that can be attained with mass spectrometry (MS) matched with chromatographic seperation.

Information about the 38th International symposium HPLC 2012 held in Anaheim in California from June 16-21, 2011 on the trends of liquid-phase chromatography is presented. Topics include ultraviolet (UV) detection, aerosol detection and column elevations in high-performance liquid chromatography (HPLC). The symposium featured the Horvath Award given to Stefan Bruns of the Philipps-University.

Supported liquid extraction (SLE) has been around for a long time, but surprisingly it is seldom used to replace classical liquid-liquid extraction (LLE). In SLE, the same organic phases used in LLE are coated onto an inert diatomaceous earth, but instead of shaking two immiscible phases together, the aqueous phase is passed through the column (or cartridge) and a very efficient extraction takes place. SLE offers many advantages over LLE, including equivalent or more efficient extraction, no emulsion formation, easy automation, less organic solvent use, less labour and less glassware. [ABSTRACT FROM AUTHOR]

The article focuses on the history and phase development trends of chiral capillary gas chromatography (GC) as of 2012. It provides a comparison of high performance liquid chromatography (HPLC) and GC chiral separations. It discusses how to choose the best stationary phase and how to use it for the optimum capability of chiral GC separations. Also described are examples of injection of big volumes of diluted sample using retention gaps, racemates' elution order reversal, and other applications.

In gas chromatography selectivity is commonly thought to be about exclusivity of the column stationary phases and sometimes extended to the detector. This instalment of "Column Watch" explains how to incorporate selectivity throughout the sample analysis cycle, from the sampling analysis cycle through data analysis and report generation. [ABSTRACT FROM AUTHOR]

The article reports on the results of a survey regarding the trends of high performance liquid chromatography (HPLC) columns. It says that the survey focused on aspects such as mode and stage of use, particle size and buying decision factors. The survey revealed that liquid chromatographers used an average of 3.2 methods in solving separation problems. Tables of data on the results such as the HPLC device used, analytical methods and particle sizes are also presented.

In this instalment of "Sample Preparation Perspectives," Norwegian authors from the University of Oslo describe the practical aspects of hollow fibre liquid-phase microextraction in the three-phase mode (HF3LPME). The guest authors highlight important practical issues related to the supported liquid membrane, the hollow fibre and the extraction itself. They also discuss practical work with electromembrane extraction (EME), which is related to HF3LPME but uses an electrical potential as the driving force for the extraction. [ABSTRACT FROM AUTHOR]

With the recent emphasis on high-throughput high performance liquid chromatography (HPLC) and ultrahigh-pressure liquid chromatography (UHPLC), chromatographers are looking for ways to improve productivity. This instalment discusses the use of method translation calculators to make conversions from conventional HPLC to high-throughput HPLC and UHPLC more convenient to perform without the need for manual calculations. Both isocratic and gradient method translations are discussed and applications are demonstrated. [ABSTRACT FROM AUTHOR]

The article discusses the significance of using Gas Chromatography (GC) Method Translation Software in chromatography laboratories. It notes the complexities in analyzing and adopting methods for fast GC and separation efficiency. However GC software helps provide faster and efficient carrier gas and column dimensions in chromatographic processes.

An interview with inventors Michelangelo Anastassiades and Steve Lehotay is presented. When asked about the major improvements in the extraction protocols for pesticide analysis, they mention the aid of original method in experiments and current modifications, which includes buffering, addition of C18, and reduction of chlorophyll. Further, it explores on the major difficulties in advancing the QuEChERS methodology, the advantages and disadvantages, the matrices involved, and its applications.

For decades, reversed-phase (RP) chromatography has dominated HPLC applications. Almost as soon as bonded reversed phases became available in the early 1970s, this mode surged ahead as the most popular. Through the years, the technique has become more efficient, columns more stable, and new types of phases beyond the traditional C8 and C18 give different selectivity that is required for more difficult separations. Here, we focus on the characterization of reversed-phase columns with particular emphasis on the hydrophobic-subtraction model. A well-attended Pittcon 2010 session brought together many experts to update our knowledge in this area and help liquid chromatographers make more educated decisions on phase selection and usage. [ABSTRACT FROM AUTHOR]

Columnist Ron Majors discusses some of the practical considerations in the successful application of the popular yet age-old technique of solvent extraction (also known as liquid-liquid extraction, or LLE). After a brief review of the basics, guidelines on the selection of the appropriate extraction solvents and how to use acid--base equilibria to ensure efficient extractions of ionic and ionizable compounds are provided. Problems in LLE and the solutions to these problems are highlighted. A newer technique called dispersive liquid-liquid microextraction (DLLME) is introduced. [ABSTRACT FROM AUTHOR]

In this instalment of "Column Watch", columnist Ron Majors examines the role of pressure in high performance liquid chromatography (HPLC) from two viewpoints: the impact of the ultrahigh pressures encountered in ultrahigh-pressure liquid chromatography (UHPLC) on chromatographic parameters and increases in column pressure encountered in normal daily use. The latter is of more practical consequence to HPLC users because increased back pressure usually implies that something has gone wrong with the column. Pressure increases as a result of physical and chemical contamination are explored and practical approaches to solve these problems are suggested. [ABSTRACT FROM AUTHOR]

Selective sample preparation techniques are particularly attractive for the analysis of trace amounts of small molecules in complex matrices. In this month's instalment, columnist Ron Majors covers the field of immunoextraction, a technique that employs immobilized antibodies to selectively capture specific analytes using molecular recognition via antibody-antigen interactions. Recently, the introduction of commercial products for specific high-volume environmental and food safety applications should spur further applications of this technique. [ABSTRACT FROM AUTHOR]

This month's instalment of "Sample Prep Perspectives" describes a new extraction technique called QuEChERS (standing for quick, easy, cheap, effective and safe and is pronounced "catchers") for the sample preparation of pesticides in foods and agricultural samples. The technique uses simple glassware, a minimal amount of organic solvent and various salt/buffer additives to partition analytes into an organic phase for clean up by dispersive solid-phase extraction (d-SPE). The technique provides good recoveries, is reproducible and costs less than other sample preparation approaches. The technique is being adopted by many laboratories worldwide. It has the potential for applications outside of the pesticide in foods area. [ABSTRACT FROM AUTHOR]

Although the majority of solid-phase extraction (SPE) is performed with conventional bonded silica- and polymeric-phases, difficult and complex samples may require more specialized stationary phases. In this instalment of ‘Sample Preparation Perspectives’, columnist Ron Majors discusses advanced topics such as multimodal SPE, restricted-access media, molecular imprinted polymers, immunoaffinity extraction phases and other class- or compound-specific sorbents. These phases provide additional selectivity and procedures using them can be automated. Representative applications will be presented. [ABSTRACT FROM AUTHOR]

Traditional methods for the sample preparation of insoluble solid materials have represented one of the more time consuming and labour-intensive efforts in analysis. In this instalment of ‘Sample Prep Perspectives’, Ron Majors examines modern sample preparation methods for solids that often involve increased temperature and higher pressure to speed up the extraction process. In addition, modern sample preparation methods have been automated to relieve analysts of the drudgery associated with traditional methods. Here, he reports on automated Soxhlet extraction, supercritical fluid extraction, pressurized fluid extraction-accelerated solvent extraction, and microwave-assisted extraction and updates earlier coverage. [ABSTRACT FROM AUTHOR]

In any field there are often ‘misconceptions’ or ‘myths’ that are perpetuated and passed on to the next generation. These myths are often driven by a lack of understanding by practitioners of the real issues. In this instalment of ‘Column Watch’, the 10 most popular myths around high performance liquid chromatography (HPLC) column technology will be demystified by discussing the issues at hand. Among some of the popular myths that will be dispelled are that ‘All C18 (L1) columns are the same’, ‘You can't reverse an HPLC column’, ‘High temperature always leads to better separations’ and ‘The higher the carbon load the better the reversed-phase column’. [ABSTRACT FROM AUTHOR]

Higher productivity end faster analyses are two of the driving forces for continued improvement in high performance liquid chromatography (HPLC column technology. Reduction in the average particle size of HPLC porous column packings below 2 µm has resulted in sub-1.0 min separations in the gradient and isocratic modes. In this instalment of "Column Watch", Ron Majors traces the development of particle technology from the beginning of HPLC to the present discusses why mall particles am desirable, and probes some of the difficulties to be encountered, including extracolumn band broadening, pressure restrictions, and instrumental considerations. Finally, he shows a wide variety of fat- and ultrafast applications examples from commercial products in the sub-2 µm range. Speculation on future directions in HPLC in particle technology concludes the column. [ABSTRACT FROM AUTHOR]

Liquid-liquid extraction (LLE) is among the most widely used sample preparation methods. In this month's instalment of ‘Sample Preparation Perspectives,’ Ron Majors discusses newer LLE approaches that offer significant advantages over classic methods. The miniaturization of LLE has resulted in solvent and time savings, improved automation possibilities and faster sample preparation. The techniques of single-drop microextraction, extraction in levitated droplets, flow injection-, membrane-based- and solid-supported extractions are reviewed. Often, these techniques use the same immiscible solvent pairs of conventional LLE. [ABSTRACT FROM AUTHOR]

Protein-based drugs are a rapidly growing segment of the prescription drug market and must be isolated in large quantities. The starting material for many of these drugs is of cell origin, and the proteins must first be isolated from the myriad of undesired cell contents. Sample preparation and purification procedures suitable in the laboratory might not be scaled up to production processes easily. Here, Ron Majors discusses methods that can be used to isolate large amounts of proteins from crude biological samples. Discussed are mechanical and chemical cell disruption, clarification of disrupted cellular materials using centrifugation, filtration, flocculation and coagulation, and product concentration. [ABSTRACT FROM AUTHOR]

The micropipette tip containing solid phases is a relatively new sample preparation format that permits the handling of microlitre and submicrolitre amounts of liquid samples using the techniques of solid-phase extraction, dialysis and enzyme digestion. Phases are packed, embedded or coated on the walls of the pipette, permitting liquid samples to be moved and transferred without undue pressure drop or plugging. This column reviews the latest technologies in micropipette tip sample preparation used in the study of genomics, proteomics and metabolomics. [ABSTRACT FROM AUTHOR]

When a column is replaced with a new or "equivalent" column, sometimes the chromatogram can change so much that it is no longer suitable for its intended use. In such instances, method adjustment is necessary to correct the change. How much can the chromatographic variables be changed before revalidation is required? What do the regulatory agencies have to say about method adjustment? The authors discuss these issues and propose a technique that can be used to speed selection of new operating conditions. [ABSTRACT FROM AUTHOR]

This month's "Sample Preparation Perspectives" reviews some key considerations in the manufacture and use of microplates, particularly the 96-well plate, which has revolutionized laboratory automation and permits reduction of labour and sample, reagent and solvent requirements. [ABSTRACT FROM AUTHOR]

This article presents a discussion of preparative chromatography which focuses on the columns used in preparative high performance liquid chromatography, including how to select the appropriate mode, mobile-phase system and operating conditions. The column is the heart of the liquid chromatograph. Choice of the wrong column and mobile-phase conditions for the sample at hand can trivialize all of the advantages of expensive, sophisticated instrumentation and data systems. In preparative chromatography, this statement is also true. An unsuitable column-mobile-phase combination can be disastrous, with possible sample precipitation wreaking havoc on expensive wide-bore preparative columns and instrumentation.

This report aims to provide information about many of the new separation consumables and accessory products that were displayed at Pittcon 2004 conference. The information is based upon manufacturers' responses to a questionnaire mailed in December 2003. The report discusses gas chromatography columns, sample preparation products, hardware, accessories and kits for chromatography and sample preparation. Eight companies contributed new Gas Chromatography column information for Pittcon 2004, and one company introduced a series of columns for analytical and preparative superficial fluid chromatography.