LC–MS

This study of a selected group of PPCP contaminants in eastern North Carolina demonstrates the advantages and disadvantages of LC–MS and GC–MS as well as SPE and liquid–liquid extraction.

An LC–MS method for simultaneous quantification of buprenorphine and three metabolites: norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide.

Validation of this rapid bioanalytical method for the determination of moxidectin in cattle hair demonstrated that the method is accurate, reliable, and reproducible.

High-resolution mass spectrometry (MS) is not readily compatible with chromatographic techniques using high-salt mobile phases. This study presents the development and use of 2D-LC–MS via an on-line desalting step for the analysis of monoclonal antibodies and antibody–drug conjugates.

Measuring trypsin inhibitors in legumes is important to feed processors, who are concerned with providing high-quality products for animal feed. In this study, a rapid, accurate, and precise method for the quantification of trypsin inhibitor activity is evaluated.

The development of various analytical MS methods to investigate the chemical composition of liquids used in electronic cigarettes and characterize their quality is presented in this study.

A review of the central role LC–MS plays in characterizing mAbs and biosimilars, including highlights of top-down and middle-up approaches to measure the intact masses of mAbs and their subunits, the current state of peptide mapping techniques, and glycoprofiling methods.

The last decade has seen a series of advances in the field of liquid chromatography that have resulted in improvements for many clinical diagnostic services. These innovations have included the expansion of superficially porous particle columns, new or improved stationary phase options, and “user-friendly” multiple-channel HPLC instrument options that allow sequential analysis-a boon for low and moderate throughput laboratories with limited hardware. As a result, diagnostic services are able to offer faster turn-around-times and measure analytes in patient types and disease states that were previously problematic. This article presents examples of the impact these innovations have had in a number of hospital settings.

Adequate detection of trans-resveratrol in wine is complicated by two factors: relatively low levels and interferences from matrix components. Here, we present two useful approaches to overcoming these issues depending on the instrumentation available. For HPLC–UV analyses, matrix peaks can be removed by microextraction using packed sorbent while simultaneously concentrating the trans-resveratrol peak by a factor of two. For LC–MS, the extracted ion chromatogram for the [M + H]+ analyte ion can be used to obtain specificity without prior extraction procedures.

This article presents a step-by-step DoE optimization strategy for an electrospray ionization source with the aim to quantitatively analyze 18 compounds in a metabolomic study of human urine.

This article provides useful tips for smooth validation of multi-analyte LC–MS-MS methods and summarizes important validation outcomes for 295 analytes, including more than 200 mycotoxins.

Non-targeted metabolite profiling by ultrahigh-performance liquid chromatography coupled with mass spectrometry (UHPLC–MS) is a powerful technique to investigate the influence of genetic and environmental influence on metabolic phenotype in plants. The approach offers an unbiased and in-depth analysis that can reveal molecular markers of desirable phenotypic traits which can be complementary to genetic markers in plant breeding efforts. Here, the power of non-targeted metabolite profiling is illustrated in a study focused on the determination of molecular markers in malting barley that are predictive of desirable malting quality for brewing applications.

Experiments presented here demonstrate the suitability of LC–SAI-MS for the detection and quantification of pharmaceuticals, with limits of detection in the low parts-per-trillion range. A comparison of LC–ESI-MS to LC–SAI-MS also yielded favorable results for SAI.

Enzyme immunoassay (EIA) is a conventional drug screening technique, but it can be limited by cross-reactivity that can lead to high false positive rates.

We recently spoke to Gary Duncan and Wendy Russell of the Rowett Institute of Nutrition & Health in Aberdeen, Scotland, about the significance of phytochemical bioavailability to human health and the important role of liquid chromatography linked to tandem mass spectrometry (LC–MS-MS) in their research.

Click here to view the complete E-Separation Solutions newsletter from February 20, 2014.

Secondary parameters in the interface and mass analyzer can have a major impact on sensitivity and reproducibility. Here, we examine how and when to consider optimizing these parameters through a study of the working principles of LC–MS analysis.

We assessed a simple method based on recovery for the detection of matrix effects and two alternative methods for the rectification of matrix effects in LC–MS: standard addition and the coeluting internal standard method.

Redox reactions are integral parts of many cellular processes. Thus, they are extensively studied in vitro and in vivo. Electrochemistry (EC) represents a pure instrumental approach to characterize direct and indirect effects of redox reactions on bioorganic molecules.

5-Fluorouracil (5-FU) is a low-molecular-weight anticancer drug in clinical use for several solid tumors in humans. Currently, the most widely used methodology for 5-FU quantitation is liquid chromatography–tandem mass spectrometry (LC–MS-MS) with either liquid–liquid extraction (LLE), protein precipitation, or a combination of both as sample cleanup procedures.

This article examines the problem of dermorphin doping in horse racing and presents an effective method for its detection using LC–MS TQ.

Hyphenated approaches to analysis have received much attention over the last three decades to the extent that techniques such as GC?MS, GC?FTIR and LC?MS have ? in the relevant fields ? become indispensable parts of the analyst?s arsenal. This concept has been extended to include multi-hyphenated techniques, where the chromatography is preceded by analyte extraction from a sample matrix. In the field of GC?MS, examples include thermal, sorptive or headspace extraction, with subsequent preconcentration, for instance, by thermal desorption (TD).

This article describes the operating principles of the direct-electron ionization (EI) interface, which is becoming more popular in many LC–MS applications. Matrix effects and the role of direct-EI as a universal detector for small molecule analysis are also discussed in detail. The advantages and drawbacks of this approach are described and a comparison with atmospheric pressure ionization (API) interfaces is made. The potential of direct-EI is illustrated with a selection of practical applications.

Industry veteran Thomas Beesley takes readers on a tour of his experiences in chromatography.

Well-known industry veteran and LCGC EAB member Peter Carr looks back at the early days of the chromatography field and reflects on his own experiences.

The coauthors discuss the various attributes of and approaches to reversed-phase chromatography.

The winners of LCGC's third annual awards were announced at Pittcon 2010.

The authors examine some critical factors with regard to buffers in LC and LC-MS research.

Presented here are four types of evaporation-free extractions that are widely applicable.

Researchers from the University of Barcelona (Barcelona, Spain) analyzed heterocyclic amines in meat samples using pressurized liquid extraction followed by liquid chromatography with tandem mass spectrometry detection (LC?MS-MS).