The authors compare LC–MS/MS methods for quantification of the pesticide glyphosate with and without sample derivatization, and discuss ICP-MS methods for the determination of heavy metals.
Systematic toxicological analysis is an important step in medicolegal investigations of death, poisoning, and drug use. The primary goal is the detection and confirmation of potentially toxic compounds in evidence. This article describes a workflow using nontargeted liquid chromatography–tandem mass spectrometry (LC–MS/MS) for reliable compound identification.
In this study, regression and classification chemometrical algorithms were combined to achieve effective discrimination of pure body fluids from their binary mixtures.
FT-NIR spectroscopy can be used to overcome a range of challenges in raw material identification while also meeting the stringent requirements of regulated environments.
In life science research, detergents are primarily used in sample preparation to liberate cellular components through membrane disruption and to solubilize lipid-associated proteins.
The application note explains how the Raman Spectroscopy can be helpful in the analysis of cathodes and anodes in Li-ion batteries.
SciAps has developed a handheld analyzer based on laser induced breakdown spectroscopy (LIBS).
Chromium is a key ingredient in a number of metal alloys used for metal implants which, despite being coated with inert surface layer coatings, can break down over time as a result of biocorrosion. Leeching of metal ions from implants into surrounding bone, tissue, and body fluids can cause severe health problems. Although the toxicity of the metal is low, there is a potential health risk if chromium ions enter the body. In ICP-MS, the chromium (52Cr) signal can be affected by interference from the recombination of background plasma 40Ar and sample-specific matrix 12C. To eliminate this interference, hydrogen can be used in the iCRC as a reaction gas to allow accurate analysis of 52Cr. Results using certified clinical standards of chromium in blood, plasma, urine, and serum clearly demonstrate the benefit of using hydrogen as a collision gas to remove the argon-carbide polyatomic interference. This study shows that ICP-MS is an essential tool for clinical monitoring of metal ions in complex matrices and that hydrogen iCRC gas allowed for greater accuracy and a lower level of quantitation in clinical matrices.
In life science research, detergents are primarily used in sample preparation to liberate cellular components through membrane disruption and to solubilize lipid-associated proteins.
The power of nontargeted 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. The metabolite extraction, detection, and analysis methods are highthroughput and reproducible, and therefore, this approach represents a practical addition to the plant breeder’s molecular toolbox.
In life science research, detergents are primarily used in sample preparation to liberate cellular components through membrane disruption and to solubilize lipid-associated proteins.
This article presents developments in tip-enhanced Raman spectroscopy (TERS) that make possible nanoscale imaging of chemical and physical properties of graphene and other carbon species: Innovative integration of technologies brings high-throughput optics and high-resolution scanning for high-speed imaging without interferences between the techniques.
The authors investigated the analytical capabilities of three types of mass analyzers for liquid chromatography-mass spectrometry (LC-MS) applications, studying the effects of instrument parameters and issues related to sample preparation on the performance of LC-MS analytical methods.
The transition of cannabis from an illegal drug to a drug for medical and even recreational use raises challenging questions for regulatory agencies and analytical chemists alike. Here, we show a selection of analytical techniques based on compact mass spectrometry in combination with three different sample inlets (atmospheric solids analysis probe), thin-layer chromatography, as well as classical liquid chromatography) for the detection and quantification of cannabinoids and pesticides in cannabis-related material and contraband.
Melamine is a dangerous substance when it is used to increase the apparent protein content of food. In this article, the use of novel gold nanoparticles for surface-enhanced Raman spectroscopy (SERS) measurements with raster orbital scanning sampling is described for the detection of melamine and other food contaminants.
A rapid, accurate, and precise method for the quantification of trypsin inhibitor activity was evaluated. The method utilizes alpha hydroxyl acid capped oligo-lysines [hydroxy acid (Lys)n] or alpha hydroxyl acid capped oligo-lysines-methionine [hydroxy acid (Lys-Met)] as substrates. Hydrolysis of the oligopeptides yields unique chemical residues that were readily quantified with electrospray–mass spectrometry (ESI-MS). Accuracy and precision of the approach compared favorably with that of the standard test method.
Highlights of recent advances in three major areas of molecular spectroscopy: infrared (IR), Raman, and fluorescence.
This article presents developments in tip-enhanced Raman spectroscopy (TERS) that make possible nanoscale imaging of chemical and physical properties of graphene and other carbon species: Innovative integration of technologies brings high-throughput optics and high-resolution scanning for high-speed imaging without interferences between the techniques.
This article investigates the use of gas chromatography–time-of-flight mass spectrometry (GC–TOF MS) to fragrance-profile three essential oils (ginger, wintergreen and rosemary). As well as considering the compositional differences between the oils, we will examine the use of peak deconvolution to identify closely-eluting compounds, and explore the use of soft electron ionization, assisted by comparison of ion ratios, to discriminate between isomeric monoterpenes that are difficult to identify at conventional 70 eV ionization energies due to their very similar mass spectra.
Mass spectrometry has long been a preferred tool for protein identification and biomarker discovery, but preparation of biological samples remains a challenge. Hindrances include the wide range of protein concentrations, sample complexity, and loss or alteration of important proteins due to sample handling. This article describes recent developments in sample fractionation technologies that are overcoming these challenges in interesting ways and are enabling in-depth proteomic studies that were not possible in the past.
The purpose of this study was the development of various analytical MS methods to investigate the chemical composition of e-liquids used in electronic cigarettes and characterize their quality. Low-quality nicotine (the main active compound), glycerol, propylene glycol (solvents), or flavors could greatly increase the toxicity. The search of alkaloid contaminants of nicotine was performed by LC–MS-MS after a deep study of fragmentation pathways by high resolution ESI-MS. A fully validated method for quantitation of organic polar impurities such as cotinine, anabasine, myosmine, nornicotine, and N-nitroso-nornicotine and nicotine itself was developed using MS coupled to UHPLC. To evaluate organic volatile toxicants, headspace from e-cigarette refill liquids was sampled by SPME to perform GC–MS analysis. Finally, heavy metal residues as inorganic toxicants were determined by ICP-MS after simple dilution. A number of cases of contamination by metals (mainly arsenic) was detected.
Nebulizer selection is a critical but often overlooked aspect of inductively coupled plasma–optical emission spectroscopy (ICP-OES) analyses. There are many different nebulizers available for ICP-OES, and choosing the optimal one can be confusing and difficult. To achieve peak performance from your ICP, it is essential to choose the proper nebulizer based on your sample types in addition to any necessary accessories to maintain long-term performance. In this study, we compare the performance of Glass Expansion’s most popular concentric nebulizer designs for ICP-OES applications as well as a parallel-path nebulizer from another vendor, providing a complete selection guide based on performance and design.
SERS of bacterial cells can be a useful technique for clinical diagnostics, as illustrated by the analysis of a human urine sample spiked with urinary tract infection bacteria.
The purpose of this study was the development of various analytical MS methods to investigate the chemical composition of e-liquids used in electronic cigarettes and characterize their quality. Low-quality nicotine (the main active compound), glycerol, propylene glycol (solvents), or flavors could greatly increase the toxicity. The search of alkaloid contaminants of nicotine was performed by LC–MS-MS after a deep study of fragmentation pathways by high resolution ESI-MS. A fully validated method for quantitation of organic polar impurities such as cotinine, anabasine, myosmine, nornicotine, and N-nitroso-nornicotine and nicotine itself was developed using MS coupled to UHPLC. To evaluate organic volatile toxicants, headspace from e-cigarette refill liquids was sampled by SPME to perform GC–MS analysis. Finally, heavy metal residues as inorganic toxicants were determined by ICP-MS after simple dilution. A number of cases of contamination by metals (mainly arsenic) was detected.