Volatile organic compounds (VOCs) in exhaled human breath can serve as potential disease-specific and exposure biomarkers and therefore can reveal information about a subject's health and environment. Pyridine, a VOC marker for exposure to tobacco smoke, and isoprene, a liver disease biomarker, were studied using atmospheric pressure chemical ionization mass spectrometry (APCI-MS). While both m...

A method for the simultaneous determination of lutein and zeaxanthin stereoisomers by HPLC-DAD was developed. For this purpose, (Z)-isomers of lutein and zeaxanthin were prepared by iodine-catalyzed photoisomerization and their structures elucidated by 1Dand 2D-LC-NMR spectroscopy, by APcI-MS in the positive mode, and by UV/Vis spectroscopy. Near baseline separation was achieved for (13-Z)-lute...

The analysis of brominated flame retardants (BFRs) commonly relies on the use of gas chromatography coupled to mass spectrometry (GC-MS) operating in electron ionization (EI) and electron capture negative ionization (ECNI) modes using quadrupole, triple quadrupole, ion trap, and magnetic sector analyzers. However, these brominated contaminants are examples of compounds for which a soft and robu...

glucagon like peptide-1; Ala: Alanine; Gly: Glycine; Pro: Proline; HTS: high-throughput screening; ESI: electrospray ionization; APCI: Atmospheric Pressure Chemical Ionization; pNA: p-nitroanilide; Asp: Aspartic acid; Thr: Threonine; Met: Methionine; Phe: Phenylalanine; Leu: Leucine; Ser: Serine; HOBT: Hydroxybenzotriazole ; EDCI: 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride; Me:...

Raw space-based gravitational-wave data like LISA's phase measurements are dominated by laser frequency noise. The standard technique to make this usable for science is time-delay interferometry (TDI), which cancels noise terms forming suitable combinations of delayed measurements. We recently introduced the basic concepts an alternative approach which, unlike TDI, does not rely on independent ...

A sensitive, selective and generic method has been developed for the simultaneous determination of the contents ( g kg−1 range) of both volatile nitrosamines (VNA) and non-volatile nitrosamines (NVNA) in processed meat products. The extraction procedure only requires basic laboratory equipment and a small volume of organic solvent. Separation and quantification were performed by the developed L...

distributed in southwestern China, is a traditional Tibetan medicine used as a remedy for hepatitis and cholecystitis. Previous phytochemical investigations using this plant have led to the isolation of various poly-oxygenated xanthones, xanthone glycosides, and flavonoid glucosides. In this paper, we report the isolation and structure elucidation of two new iridoid glycosides senburiside III (...

It is well-known that the use of atmospheric pressure ionization (API) techniques, such as electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI), is associated with the formation of even-electron ions,1 for example, protonated molecules [M C H]C, adducts with alkali metal ions [M C Na]C and [M C K]C, adducts with ammonium ions [M C NH4]C in the positive-ion mode and d...