Author


Ken Miller

Latest:

Targeted Quantitative Protein Analysis in Human Serum Using High-Resolution Multiple Selected Reaction Monitoring Assays

A common endpoint for a biomarker discovery experiment is a list of putative marker proteins. The next step is then to perform targeted quantitative measurements of these proteins in an expanded patient population to assess their validity as markers. Analytical accuracy and precision are required for unambiguous quantitative analysis of targeted proteins from very complex mixtures. Wide dynamic range and high sensitivity are critical for detecting low-abundance proteins. Such an assay also is appropriate for "targeted discovery" experiments, where the goal is to quantitate a large number (up to hundreds) of known proteins in a complex sample.


Millipore

Latest:

PFAS Analysis: Challenges in Various Matrices

When detecting and analyzing PFAS, the greatest hurdles lie in the various matrices in which PFAS are found. Custom methods and extensive expertise help to solve these issues.


Robert E. Smith

Latest:

An Evaluation of the Determination of the Lipophility of Apocynin and Diapocynin using HPLC

This study evaluates the use of HPLC to estimate the log P (the octanol–water partition coefficient) of two compounds, apocynin and diapocynin. The paper will discuss the effects of an unexpected reversal of retention that occurred when these compounds were chromatographed with various amounts of methanol–water mobile phases.


José Diana

Latest:

Facilitated Column Selection in Reversed-Phase Liquid Chromatography for Pharmaceutical Separations

This article gives an overview of the performance of a previously developed system for the ranking of C18 reversed-phase columns applied to different pharmaceutical analyses. The separation of eight different drug substances from their respective impurities was studied. The chromatographic procedure for acetylsalicylic acid, clindamycin hydrochloride, buflomedil hydrochloride, chloramphenicol sodium succinate, phenoxymethylpenicillin and nimesulide was performed according to the corresponding European Pharmacopoeia monograph. The separations of dihydrostreptomycin sulphate and vancomycin were performed according to literature. It was found that that the column ranking system is a helpful tool in the selection of suitable columns in these analyses.


Erwin Adams

Latest:

The Role of Liquid Chromatography and Gas Chromatography in the Analysis of Illegal Medicines and Health Products

This review article will give a general overview of the liquid chromatographic (LC) and gas chromatographic (GC) methods used by analytical laboratories for the detection and characterization of suspected illegal medicines and health products, including lifesaving drugs (antimicrobials and antimalarials), lifestyle drugs (erectile dysfunction drugs), and biotechnology drugs (doping peptides and skin-tanning peptides). Literature published from 2015 until early 2019 will be surveyed.


Erwin R. Kaal

Latest:

On-line SEC–Py-GC–MS for the Automated Comprehensive Characterization of Copolymers

The pyrolysis fragments are first refocused on the top of the GC column, then separated and finally detected by the MS. At the end of the GC run the SEC flow is resumed again and the entire process is repeated.


John Oosdijk

Latest:

Fast Analysis of Malt Whisky by GC–MS Using an Ultra High Performance VF-WAXms Column from Varian, Inc.

The flavours of malt whisky result from a complex blend of long chain esters and alcohols, derived from the distillation products and the composition of the wooden barrels in which the finished product is aged. As shown below, the new VF-WAXms column from Varian, Inc. is ideal for analysing whisky, especially when trace analysis is needed. The column's ultra-low bleed increases sensitivity, extends column life and improves accuracy, even at higher temperatures. In addition, VF-WAXms columns are suitable for use with MS detectors, as the ultra low bleed eliminates interferences and permits more sensitive detection.


Hamed Eghbali

Latest:

Pressure-driven Chromatography in Perfectly Ordered Pillar Array Columns

his article reveals the first liquid chromatography (LC) separations performed on a microfabricated pillar array column under pressure-driven conditions. The pillars were non-porous and produced using a Bosch-type deep reactive ion etch (DRIE) to pattern the surface of a silicon wafer and had a diameter of approximately 5 μm. Two different packing densities were compared: one similar to the packing density of a packed bed (external porosity of approximately 49%) and one similar to the packing density of monolithic columns (external porosity of approximately 70%).


Philipp Weller

Latest:

A Miniaturized Method to Determine Epoxidized Soybean Oil in Baby Food

This article describes the development of a routine method to analyse epoxidized soybean oil (ESBO) in baby food...


Pierre Gareil

Latest:

CE–MS-MS for the Identification of Chemical Warfare Agent Degradation Products

With the threat of terrorism growing, the development of analytical techniques for the detection and identification of chemical warfare agent defradation products has increased. Capillary electrophoresis (CE) presents interesting features for this application.



Dóra Visky

Latest:

Facilitated Column Selection in Reversed-Phase Liquid Chromatography for Pharmaceutical Separations

This article gives an overview of the performance of a previously developed system for the ranking of C18 reversed-phase columns applied to different pharmaceutical analyses. The separation of eight different drug substances from their respective impurities was studied. The chromatographic procedure for acetylsalicylic acid, clindamycin hydrochloride, buflomedil hydrochloride, chloramphenicol sodium succinate, phenoxymethylpenicillin and nimesulide was performed according to the corresponding European Pharmacopoeia monograph. The separations of dihydrostreptomycin sulphate and vancomycin were performed according to literature. It was found that that the column ranking system is a helpful tool in the selection of suitable columns in these analyses.



Tawakol A. El-Shourbagy

Latest:

High-Throughput Quantitative LC-MS-MS Assays by On-Line Extraction Using Monolithic Support

LC-MS-MS has become a widely used technique for the fast and sensitive quantitation of small molecules. In this article, this approach has been extended to high-throughput quantitative LC-MS-MS analysis under GLP applications for a drug candidate in development from preclinical animal studies through clinical development.


Thomas Zey

Latest:

Automated High-Throughput Formula Determination and Confirmation with "sub-ppm" Confidence

Combining an ultra fast LC system (e.g., Agilent 1200RRLC, Waters UPLC) with an accurate mass TOF mass spectrometer creates a powerful system for information-rich high-throughput analyses. However, for de novo formula generation and confirmation the residual mass accuracy tolerance of 3–5 ppm can still leave significant ambiguity in the proposed formula. Consequently, skilled manual inspection or further measurements deploying additional analytical techniques (NMR or MS–MS) are frequently required to arrive at a confident formula assignment.


Fang Xia

Latest:

A Quick and Accurate High Performance Liquid Chromatography (HPLC) Method to Determine the Amount of Trimethylamine in Fish Oil Softgels and Multivitamin Softgels Containing Fish Oil

A HPLC method was developed to measure trimethylamine in fish oil supplements, to determine if the level of this compound affects product quality attributes such as rancidity.


Ron Luchtefeld

Latest:

An Evaluation of the Determination of the Lipophility of Apocynin and Diapocynin using HPLC

This study evaluates the use of HPLC to estimate the log P (the octanol–water partition coefficient) of two compounds, apocynin and diapocynin. The paper will discuss the effects of an unexpected reversal of retention that occurred when these compounds were chromatographed with various amounts of methanol–water mobile phases.


Birgit Schneider

Latest:

Analysis of Secondary Metabolites from Myxobacteria using ESI-TOF–MS and PCA

The exploration of myxobacterial metabolite profiles by LC–MS screening for the presence of new natural products is described. Extracts from fermentations of Myxococcus strains are analysed by UPLC-coupled ESI-TOF mass spectrometry and the obtained data are processed using principal component analysis (PCA). The generation of molecular formulae from accurate mass measurements facilitates rapid compound identification.


Izumi Waki

Latest:

Electron-Capture Dissociation in a Radio-Frequency Linear Ion Trap

Here we describe a new compact device for electron-capture dissociation (ECD) analysis of large peptides and posttranslational modifications of proteins, which can be difficult to analyze via conventional dissociation techniques such as collision-induced dissociation (CID). The new compact device realizes ECD in a radio frequency (RF) linear ion trap equipped with a small permanent magnet, which is significantly different than the large and maintenance-intensive superconducting magnet required for conventional ECD in Fourier-transform ion cyclotron resonance mass spectrometers. In addition to its compactness and ease of operation, an additional merit of an RF linear ion trap ECD is that its reaction speed is fast, comparable to CID, enabling data acquisition on the liquid-chromatography (LC) time scale. We interfaced the linear-trap ECD device to a time-of-flight mass spectrometer to obtain ECD spectra of phosphorylated peptides injected into a liquid chromatograph, infused glycopeptides, and intact small..


Daron Decker

Latest:

The Art and Science of GC Capillary Column Production

In this month's issue, columnist Ron Majors and coauthors discuss the important steps in the successful production of fused-silica gas chromatography (GC) capillary columns.


Jérôme Ledauphin

Latest:

Chemical Characterization of Calvados (Apple Brandy) Young Spirits: Separation of Polar and Non-Polar Volatile Compounds

Calvados is an apple-brandy of Normandy (France). Mashed apples are fermented to obtain cider and then distilled to give the young spirit.


Ines Hädrich

Latest:

Improved LC–MS Performance — A Three-Step Method for Minimizing Background Signals and Increasing Ionization Efficiency

One problem frequently encountered in LC–MS is the appearance of mass peaks, which appear totally unrelated to the samples run - "ghost" mass peaks. It is impossible to differentiate whether these signals come from an unknown component in the sample co-eluting with a known peak, or from an impurity in the mobile phase or from some residual contamination "bleeding" from the column.


Ryan S. McCarthy

Latest:

HPLC Analysis of Non-volatile Analytes Using Charged Aerosol Detection

A detection method based upon aerosol charging was examined for its applicability and performance with high performance liquid chromatography.




Jill Polzin

Latest:

High-Throughput Quantitative LC-MS-MS Assays by On-Line Extraction Using Monolithic Support

LC-MS-MS has become a widely used technique for the fast and sensitive quantitation of small molecules. In this article, this approach has been extended to high-throughput quantitative LC-MS-MS analysis under GLP applications for a drug candidate in development from preclinical animal studies through clinical development.


Chris Pohl

Latest:

Haloacetic Acid Analysis Using Two-Dimensional Matrix-Elimination Ion Chromatography

The disinfectants commonly used to treat public drinking water can react with naturally occurring organic and inorganic matter in the source water to form disinfection byproducts such as haloacetic acids. Here, we describe the use of two-dimensional matrix-elimination ion chromatography (MEIC) for haloacetic acid analysis. This method minimizes the impact of matrix ions.


Shane Elliott

Latest:

ICP-MS: When Sensitivity Does Matter

It makes intuitive sense - the higher the sensitivity of an inductively coupled plasma–mass spectrometry (ICP-MS) system, the lower the detection limit. But there are many factors that affect the detection limit for a given isotope in a given sample. These factors include sensitivity, background noise, and interferences.


Alfred Donaubauer

Latest:

A Miniaturized Method to Determine Epoxidized Soybean Oil in Baby Food

This article describes the development of a routine method to analyse epoxidized soybean oil (ESBO) in baby food...


Christina M. Crimi

Latest:

Analysis of Pharmaceutical Residual Solvents Using Comprehensive Two-Dimensional Gas Chromatograhy

Comprehensive GCxGC was employed for the separation of ICH and USP 1, 2, and 3 pharmaceutical solvents. The significantly improved peak capacity in GCxGC allows a single method for any combination of solvents and mitigates interference due to impurities in the solvents, diluents, analyte matrices, and from column or septum bleed, through the increased separation space.