Collision-induced dissociation (CID) and electron transfer dissociation (ETD) are complementary mass spectrometric fragmentation techniques. We have used CID and ETD in different approaches to analyse tyrosine phosphorylation using a Thermo Scientific LTQ Orbitrap XL equipped with ETD.
Discover how to automatically manage all the purification steps involved in process scale chromatography including generation of the elution mobile phase, the injection of samples, the detection of molecules, and the collection of fractions.
LC–MS and CE–MS are the go-to techniques for characterizing biologics, but often help is needed from a range of other methods.
This article provides an introduction to electrochemical liquid chromatography mass spectrometry. The instrumental set-up is presented and selected applications in drug development processes are discussed.
For many years, the use of guard columns has been advocated by column manufacturers and other experts to protect and extend column lifetime and performance of analytical columns from potential damage caused by the presence of chemical contaminants and microparticulates in the sample and mobile phase.
Webinar Date/Time: Wed, Dec 7, 2022 9:00 AM EST
Trace-level analysis of VOCs in a tomato product using headspace extraction with large volume preconcentration (LVP) and multi-step enrichment (MSE)
An overview of current chromatography-based food toxicant screening is presented.
Analysis of biological samples frequently involves the identification of peptides from low amounts of complex samples. Confident identification of these peptides requires rapid generation of high quality, high sensitivity MS and MS–MS data. The maXis TOF mass spectrometer incorporates novel technical innovations, which together produce an unprecedented level of data quality, resulting in a significant increase in the number of peptides identified from challenging samples.
A rapid and environmentally friendly LC method for the simultaneous determination of 12 UV filters in cosmetic samples using ethanol as the mobile phase.
Quantification of European Union (EU)-priority polycyclic aromatic hydrocarbons (PAHs) in plant matrices is a crucial task. Various methods for enrichment and preconcentration, such as the preloaded-pipette tip solid‑phase extraction (SPE) (1), are available. Nevertheless, analyte recovery as a result of homogenization, sample preparation, and extraction are rarely discussed in the field of phytopharmacy. This study deals with the recovery in dry plant extracts, which are typically used in phytopharmaceuticals and reflect the actual polycyclic aromatic hydrocarbon content in the commercially available end product (2). The aim of this study was to monitor benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene loss of spiked samples as a result of commonly-used sample pretreatment, extraction, filtering, and evaporating techniques in 1:1 (v/v) cyclohexane–ethyl acetate primulae flos and sambuci flos dry extracts. Results showed that improper sample preparation can lead to false results. In the case of benzo[a]pyrene with a deviation of 155% from the theoretical true value.
The misuse of androgenic anabolic steroids in sports was banned in 1976 by the International Olympic Committee and global sports community. The illegal use of anabolic steroids has reached disturbing levels worldwide. This worldwide problem is fueled partially by an ever-increasing demand for better athletic performance. The World Anti-Doping Agency has formulated strict guidelines for minimum allowable concentrations of exogenous anabolic steroids and their metabolites. The standard test methods for doping control are analyzed in urine samples with trimethyl-silyl derivatization. Urine is a complex and difficult biological matrix. This research shows the advantages of using comprehensive two-dimensional gas chromatography–time-of-flight-mass spectrometry (GCÃ-GC–TOF-MS) and illustrates the capability of GCÃ-GC-TOF-MS to be an effective instrumental option for antidoping control screening.
Quantification of European Union (EU)-priority polycyclic aromatic hydrocarbons (PAHs) in plant matrices is a crucial task. Various methods for enrichment and preconcentration, such as the preloaded-pipette tip solid‑phase extraction (SPE) (1), are available. Nevertheless, analyte recovery as a result of homogenization, sample preparation, and extraction are rarely discussed in the field of phytopharmacy. This study deals with the recovery in dry plant extracts, which are typically used in phytopharmaceuticals and reflect the actual polycyclic aromatic hydrocarbon content in the commercially available end product (2). The aim of this study was to monitor benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene loss of spiked samples as a result of commonly-used sample pretreatment, extraction, filtering, and evaporating techniques in 1:1 (v/v) cyclohexane–ethyl acetate primulae flos and sambuci flos dry extracts. Results showed that improper sample preparation can lead to false results. In the case of benzo[a]pyrene with a deviation of 155% from the theoretical true value.
A simple and rapid HPLC method was established to simultaneously determine the active ingredients of red clover.
This article describes open access sofware for the modelling and prediction of retention times in gas and liquid chromatography. This software provides useful results for food analysis.
The tutorial sessions at HPLC 2018 are part of the conference’s educational mission. The sessions consist of presentations given by experts on various topics, with more background provided than might be presented in a typical 20-minute talk.
The coauthors discuss the various attributes of and approaches to reversed-phase chromatography.
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.
Most proteins, particularly soluble and membrane-bound proteins expressed in the endoplasmic reticulum, are glycosylated. The extent and result of glycosylation varies.
Mass spectrometry plays an increasingly significant role in the analysis of residues and contaminants in food. Here we will illustrate how the combination of ultrahigh-pressure liquid chromatography (UHPLC) and high-resolution time-of-flight-mass spectrometry (TOF-MS) is used to generate a screen of veterinary drug residues in products of animal origin. The use of UHPLC–TOF-MS and dedicated, workflow directed software allows rapid screening for large numbers of residues and automated quantification of positive samples. In addition, we illustrate how the data generated using MSE acquisition mode enable critical structural information to be collected, which offers additional selectivity and confirmatory data for compound identification and facilitates elucidation of the structure of newly discovered compounds.
Two-dimensional gas chromatography (GC×GC) and chemometrics are leading the way in new strategies on multivariate data analysis. Using GC×GC in untargeted analysis reveals how far the technique has advanced the field of separation science.
A number of clinical situations now call for high-sensitivity measurement of estrogens, including monitoring during female hormone replacement therapy, antiestrogen treatment, and estrogen deficiency in men. Traditional immunoassay methods and liquid chromatography–tandem mass spectrometry (LC–MS-MS) do not provide the sensitivity and selectivity required for these applications. In contrast, a gas chromatography–negative chemical ionization–tandem mass spectrometry (GC–NCI-MS-MS) platform can provide detection limits below 1 pg/mL when used in conjunction with the appropriate derivatization protocol, with very short cycle times.
On-line heart-cut LC–GC and, more recently, comprehensive LC–GC (LC?GC) are very powerful analytical techniques because of the combination of the selectivity features of LC with the high efficiency of GC. This article presents an overview of the most recently used interfacing systems, as well as applications in the food analysis.
Toxicology Laboratory at the Veterans Administration, Portland, Oregon, USA, Agilent Technologies
Therapeutic peptides represent one of the fastest growing segments in the pharmaceutical market. To bring these products to the market in a consistent manner, high quality is a major concern and requires stringent quality control (QC) methods. This article discusses the potential of zwitterionic chiral ion-exchangers to support peptide analysis and quality control as a flexible complementary tool to monitor the stereochemical integrity and chemical modifications.
Doug Kitson looks at some of Poland's leading separation science groups.
Separation scientists frequently encounter critical pairs that are difficult to separate in a complex mixture. To save time and expensive solvents, an effective alternative to conventional screening protocols or mathematical peak width reduction is called iterative curve fitting.
The development of analytical instrumentation for harsh terrestrial environments and outer planet space exploration exponentially increases instrument requirements-for features such as robustness, autonomous operation, and speed-and poses unique system integration challenges. Here, we explore the use of laser thermal desorption coupled to comprehensive two-dimensional gas chromatography (LTD-GC×GC) for use with a compact, high-resolution mass spectrometer for challenging applications.
A novel approach is described for the quantitation of three additives typically used in copper plating using a dual LC system with an ECD and a CAD.
The screening of pesticides, mycotoxins, and veterinary drugs is of great importance in regulated environments such as food or feed analysis. Due to some of the limitations of traditional triple quadrupole approaches (for example, targeted analyte detection, limited number of compounds, and unidentified unknown compounds), there is currently a trend towards use of full-scan MS data for the analysis of residue samples. Current screening approaches mainly rely on the use of ToF instruments coupled to U-HPLC delivering mass accuracy (~5 ppm) at a maximum resolution of <15,000. This can produce inaccurate mass measurements due the presence of unresolved background matrix interferences. In this work we show a full-scan MS screening approach with the Thermo Scientific Exactive mass spectrometer, a novel single-stage Orbitrapâ„¢ MS capable of providing precise mass accuracies at resolutions of up to 100,000 without the need for internal mass calibration.