Identification of two novel trace impurities in mobile phases prepared with commercial formic acid.

Unlabelled: While liquid chromatography/high-resolution mass spectrometry (LC/HRMS) is a versatile analytical technique, it is also sensitive to trace impurities. These impurities may come from a variety of sources, including reagents, solvents, and the sample matrix itself. Impurities in reagents may become concentrated and elute as peaks when a gradient method is used, and these peaks may cause suppression of peaks of interest both in the electrospray source, as well as in the C-trap in systems that contain one.

Determination of Neurotoxic Acetogenins in Pawpaw (Asimina triloba) Fruit by LC-HRMS.

The concentrations of the neurotoxins, annonacin and squamocin, were determined in a lyophilized sample of the fruit pulp of the North American pawpaw (Asimina triloba) by LC coupled to high resolution mass spectrometry or LC-HRMS. The sample was extracted using dry methanol at 100 °C and 10 MPa pressure in a sealed container. The extraction of annonacin and squamocin was optimal at 100 °C with 7.

Determination of mercury in ayurvedic dietary supplements that are not rasa shastra using the hydra-C direct mercury analyzer.

Mercury has been determined in Ayurvedic dietary supplements (Trifala, Trifala Guggulu, Turmeric, Mahasudarshan, Yograj, Shatawari, Hingwastika, Shatavari, and Shilajit) by inductively coupled plasma-mass spectrometry (ICP-MS) and direct mercury analysis using the Hydra-C direct mercury analyzer (Teledyne Leeman Labs Hudson, NH, USA). Similar results were obtained from the two methods, but the direct mercury analysis method was much faster and safer and required no microwave digestion (unlike ICP-MS). Levels of mercury ranged from 0.

Development and validation of ethylenethiourea determination in foods using methanol-based extraction, solid-phase extraction cleanup and LC-MS/MS.

To response to the need for a rapid, cost-effective, eco-friendly and efficient extraction process, a sensitive method for the determination of ethylenethiourea (ETU) in food matrices by high-performance liquid chromatography-mass spectrometry (HPLC-LC/MS) was developed and validated. ETU was extracted from food commodities with methanol, cleaned up by alumina-SPE column, and then determined by HPLC-MS/MS. The MS detection was operated in positive ionization mode.

Network medicine and high throughput screening.

A new paradigm is emerging in modern drug discovery. It is a fusion of traditional and modern medicine, phenotypic and targeted drug discovery, or systems and reductionist thinking. This is exemplified by using a combination of network medicine and high throughput screening.

Finding of pesticides in fashionable fruit juices by LC-MS/MS and GC-MS/MS.

Products labelled as containing extracts from two mushrooms (cordyceps plus reishi) and the juices from açaí, goji, mangosteen, noni, pomegranate, and sea buckthorn have been analysed for 174 different pesticides, using the validated QuEChERS method for sample preparation and electrospray LC-MS/MS in the positive ion mode for analysis. Pesticides were found in 10 of the 21 samples analysed. Most pesticides found were below the tolerance levels (1-6 μg/g, depending on the pesticide), but some were not.

Fast screening of lovastatin in red yeast rice products by flow injection tandem mass spectrometry.

Drug adulteration in dietary supplement materials is a world-wide problem and poses a regulatory challenge. Red yeast rice is a product used by consumers to lower blood levels of cholesterol. While most current methods to analyze red yeast rice are based on HPLC separation with a photo-diode array detector and/or a mass spectrometry detector, which takes 20-40min analysis time per sample, we developed a method to do fast screening of the active compound lovastatin by direct infusion into a mass spectrometer.

Collaborative validation of the QuEChERS procedure for the determination of pesticides in food by LC-MS/MS.

Seven FDA pesticide laboratories collaborated to develop and validate an LC-MS/MS method to determine 173 pesticides in <20 min. The average determination coefficient (r²) was >0.99 for all but two compounds tested.

"Cross-talk" in scheduled multiple reaction monitoring caused by in-source fragmentation in herbicide screening with liquid chromatography electrospray tandem mass spectrometry.

Interferences, or "cross-talk", have been found for the liquid chromatorgraphy mass spectrometry (LC-MS) determination of chlorophenoxy acid (CPA) herbicides. The time-scheduled multiple reaction monitoring (MRM) of m/z 161.0→125.

Determination of polycyclic aromatic hydrocarbons (PAHs) in shrimp.

A simple and rapid method for determining polycyclic aromatic hydrocarbons (PAHs) in shrimp is described. For sample preparation, the quick and simple QuEChERS procedure was used. Reverse-phase chromatography using an octadecyl silica (C18) column and water/acetonitrile gradient elution was used to separate analyte mixtures.

Determining the effect of calcium cations on acrylamide formation in cooked wheat products using a model system.

A model system was used to cook wheat flour and water dough pieces in sealed pressure tubes under controlled pH conditions and with various additives in the recipe water to determine acrylamide (AA) formation and elimination. The potential effectiveness of calcium as CaCl2 or CaCO3 salts to reduce the formation of AA in wheat based food products was assessed. Since the divalent Ca2+ was capable of inducing significant pH reduction in the dough, and pH lowering is known to reduce AA formation, it was necessary in some cases to adjust the pH before cooking or use a pH matched control.

Dose formulation and analysis of diapocynin.

Procedures based on high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and liquid chromatography-mass spectrometry (LC-MS) are described for analyzing diapocynin. Diapocynin was synthesized by oxidative coupling of two apocynin monomers, through the in situ generation of sulfate radicals. It was purified by washing 3 times each with boiling water, followed by boiling methanol.

Sources of variability of acrylamide levels in a cracker model.

Surveys determining amounts of acrylamide formed as a byproduct of cooking in frequently consumed fried and baked foods have sometimes found variability in the levels, even when comparing items having similar ingredients and cooking procedures. To better understand the sources of variability, the effects of different ingredients on formation and elimination of acrylamide were studied in a model system based on wheat flour and water, that resembled crackers. It was found that NaHCO3 eliminated acrylamide.

Automated one-step supercritical fluid extraction and clean-up system for the analysis of pesticide residues in fatty matrices.

An automated supercritical fluid extraction and in-line clean-up system has been developed for organochlorine and organophosphate pesticide residues contained in fats. This procedure utilizes supercritical carbon dioxide modified with 3% acetonitrile at 27.58 MPa and 60 degrees C to extract and separate the pesticide residues from the fat on a C1 bonded phase preparative column at 95 degrees C.

Automated method for cleanup and determination of benomyl and thiabendazole in table-ready foods.

An automated solid-phase extraction (SPE) cleanup with on-line liquid chromatographic (LC) analysis was developed to determine residues of benomyl (as carbendazim) and thiabendazole in table-ready food items from the U.S. Food and Drug Administration Total Diet Study (TDS).

Extraction and cleanup of organochlorine and organophosphorus pesticide residues in fats by supercritical fluid techniques.

A supercritical fluid extraction and cleanup procedure was developed for separating organochlorine and organophosphorus pesticides from fats. Supercritical carbon dioxide modified with 3% (v/v) acetonitrile was used to extract the pesticides at 60 degrees C and separate the pesticides from the fats at 4000 psi and 95 degrees C on an in-line, C1 silica-based column. The extraction and cleanup procedure gave good recoveries for 43 of 62 nonpolar to moderately polar organochlorine and organophosphorus pesticides from fats, whereas 49 were recovered through conventional Florisil column cleanup before quantitation.