Mass Spectrometry

An LC–MS-MS method is presented that can assist with monitoring substance abuse patients who are prescribed naltrexone, a narcotic antagonist.

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.

Enhanced chromatographic resolution (GC×GC), increased resolving power with high-resolution TOF-MS, and software designed to leverage these attributes are combined to provide data that are easy to process and interpret.

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.

Is your swimming pool clean and safe? Recreational water illness, most commonly in the form of digestive tract illness or skin, ear, or respiratory infections, is often caused by water contamination. The authors present a robust method, using solid-phase extraction and high-resolution mass spectrometry, for monitoring swimming pool water.

Higher Order Mass Spectrometry Techniques Applied to Biopharmaceuticals

Recent progress in high-resolution mass spectrometry (HRMS) and liquid chromatography–mass spectrometry (LC–MS) methods for the structural characterization of brentuximab vedotin and trastuzumab emtansine are presented.

When evaluating the performance of mass spectrometers, one needs to consider the best (or most meaningful) figure of merit to use; options include instrument detection limit (IDL) and signal-to-noise ratio (S/N). In the last 15 years, vendor specifications for S/N have increased from 10:1 to greater than 100,000:1. Does that accurately reflect improvements in mass spectrometers? Although there have been many significant changes, the change in S/N specifications has been far greater than the corresponding change in method detection limits (MDL). Under appropriate conditions, S/N is a meaningful standard, but the value of any S/N must be evaluated in context of the chromatography and sample. Factors influencing the validity of vendor S/N specifications are reviewed, and the statistical alternative of IDL is presented as a replacement that is more consistent with regulatory guidelines and a more relevant indicator of instrument performance.

An analytical methodology for the characterization of the primary structure of biotherapeutic proteins using sheathless CE–ESI-MS-MS instrumentation is presented. For the first time, complete sequence coverage can be achieved using a bottom-up proteomic approach from a single analysis of a tryptic digest. In a biosimilarity assessment, a single amino acid substitution was detected.

GC–MS Analysis of Aroma Compounds in Edible Oils by Direct Thermal Desorption

To translate the enormous potential of MS into meaningful, actionable, and safe test results in the specific setting of a clinical laboratory is a very substantial challenge. It is essential to realize that reliability is not inherent to this technology but must be addressed carefully and questioned systematically.

We have developed a miniaturized, multifunctional device, called the "Single-Probe," that is capable of probing small targets and of sampling and ionizing molecular species.

A new method was developed and validated using automated on-line solid-phase extraction (SPE) with tandem mass spectrometry (MS). Urine samples were enzyme-hydrolyzed and diluted before detection. The validated method was applied to positive authentic urine samples to evaluate concordance with high performance liquid chromatography (HPLC)–MS-MS results.

An important attribute of a novel ionization process for use in mass spectrometry (MS) is its simplicity and flexibility to be hyphenated to conventional liquid-based separation methods.

The main objective of this study was to evaluate the capabilities of gas chromatography (GC) with time-of-flight mass spectrometry (MS) for screening pesticides in fruits and vegetables using a purpose-built accurate-mass database.

Digital waveform technology is emerging as a powerful tool in mass spectrometry (MS). Digital quadrupoles rely on precise control of frequency rather than voltage, which allows these devices to access a greatly extended mass range

Bryan Vining from SGS Environmental Service in Wilmington, North Carolina, reveals some of the cutting-edge research his team has performed involving dioxin analysis, and proposes some future possibilities for the direction of this field.

Marijuana, the common or slang term for cannabis in its herbal form, is one of the most widely used illicit drugs in the world.

The use of a mass spectrometer in quantitative analysis exploits its exquisite selectivity and sensitivity as a detector, allowing a signal to be ascribed to a particular chemical entity with high certainty, even when present in a sample at a low concentration. There are, however, some special considerations that are necessary when a mass spectrometer is used as a quantitative tool.

This article describes the development of a new data-independent acquisition (DIA) workflow for protein quantification that uses a mass spectrometer that combines three types of mass analyzers to achieve lower limits of detection (LOD), higher sensitivity, more accurate quantitative results, wider dynamic range, and better reproducibility than existing high-resolution accurate-mass (HRAM) tandem mass spectrometry (MS-MS) DIA workflows.

Worldwide trends in illicit drug use and production have shifted toward an increase in synthetic analogues and the emergence of new variations in their manufacture.

A multiresidue method has been developed and validated for the analysis of methylxanthines (caffeine and its metabolites) and cotinine in human plasma.

In most countries, herbal medicinal products (HMPs) are introduced into the market without proper scientific evaluation or enforced safety and toxicological studies.

Direct sample analysis coupled to high-resolution time-of-flight mass spectrometry (TOF-MS) may be effective at analyzing synthetic cathinones, especially for qualitative analysis, because it does not require potentially tedious sample preparation.