Chloride-attachment atmospheric pressure photoionisation for the determination of short-chain chlorinated paraffins by gas chromatography-high-resolution mass spectrometry.

In this work, a new gas chromatography-high-resolution mass spectrometry (GC-HRMS) method based on atmospheric pressure photoionisation (APPI) has been developed for the accurate determination of short-chain chlorinated paraffins (SCCPs) as a reliable alternative to the established methods. To the best of our knowledge, this is the first time these compounds has been analysed by GC-MS using atmospheric pressure photoionisation (APPI). Efficient ionisation of SCCPs was achieved using the new GC-APPI source by the formation of [M+Cl] adduct ions in negative ion mode using dopant-assisted APPI with a mixture of acetone/CCl (3:1, v/v).

Determination of banned dyes in red spices by ultra-high-performance liquid chromatography-atmospheric pressure ionization-tandem mass spectrometry.

This paper reports the development of an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC‒MS/MS) method to determine eight banned dyes (Sudan I-IV, Sudan Orange, Sudan Red 7B, Para Red, Rhodamine B) in turmeric, curry, and chili products. For this purpose, the feasibility of electrospray (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) for the ionization of these compounds was evaluated. The tandem mass spectrometry (MS/MS) fragmentation of all targeted compounds was studied and both multistage mass spectrometry and high-resolution mass spectrometry were used to establish the fragmentation pathways and identify common fragmentation behaviors.

Atmospheric pressure ionization for gas chromatography-high resolution mass spectrometry determination of polychlorinated naphthalenes in marine sediments.

In this work, the performance of the atmospheric pressure chemical ionization (APCI) and photoionization (APPI) was assessed to develop a new selective and sensitive gas chromatography-high resolution mass spectrometry (GC-HRMS) method for the determination of polychlorinated naphthalenes (PCNs) in sediment samples. The capability of both APCI and APPI sources for the ionization of PCNs was investigated, showing the formation of the molecular ion and the [M‒Cl+O] ion in positive and negative ion modes, respectively. Positive ion APCI provided high responses using high corona ion current, while the use of high vapour pressure dopant-solvents, such as toluene in positive mode and diethyl ether in the negative mode, was required to achieve high ionization efficiencies in APPI.

Ionic Liquid Stationary Phase for Improving Comprehensive Two-dimensional Gas Chromatographic Separation of Polychlorinated Naphthalenes.

The performance of comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) using a column combination of a non-polar stationary phase (DB-5MS) and an ionic liquid stationary phase (SLB-IL60) in the first- and the second dimension has been evaluated for the suitable separation of polychlorinated naphthalenes (PCNs). The optimization of the GC×GC-MS method was carried out using different oven temperature programs and modulation conditions, achieving the best results using a ramp temperature rate of 0.75 °C min and a modulation time of 12 s.

Gas chromatography and liquid chromatography coupled to mass spectrometry for the determination of fluorotelomer olefins, fluorotelomer alcohols, perfluoroalkyl sulfonamides and sulfonamido-ethanols in water.

In this work, the suitability of gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the multi-class determination of different families of neutral per- and polyfluoroalkyl substances (PFASs), such as fluorotelomer olefins (FTOs), alcohols (FTOHs) and fluorooctanesulfonamides (FOSAs) and sulfonamido-ethanols (FOSEs), was investigated and compared. Regarding GC-MS, the use of a semi-polar GC column (DB-624, 6%-cyanopropilphenyl 94%-dimethyl polysiloxane) allowed the adequate separation of all the compounds while chemical ionisation (CI) of positive ions as ionisation technique provided the best responses. Concerning UHPLC-MS/MS, atmospheric pressure chemical ionisation (APCI) and photoionisation (APPI) sources allowed the ionisation of all studied neutral PFASs, including FTOs for the first time.

Molecular detection of pathogens in water--the pros and cons of molecular techniques.

Pollution of water by sewage and run-off from farms produces a serious public health problem in many countries. Viruses, along with bacteria and protozoa in the intestine or in urine are shed and transported through the sewer system. Even in highly industrialized countries, pathogens, including viruses, are prevalent throughout the environment.

Tamoxifen does not prevent the mobilization of body lipids elicited by oleoyl-estrone.

Oleoyl-estrone is a powerful, slimming adipose tissue-derived signal that has biological effects widely opposed to those of its estrone moiety. The present experiment was designed to determine whether oleoyl-estrone effects on body energy are mediated by the estrogen receptor, blocked with the antagonist tamoxifen. Male Wistar rats were given daily oral doses of 10 micromol/kg d of oleoyl-estrone in oil containing 0 or 0.