Nicotinic acid, N-methylpyridinium ion, and trigonelline are well studied nutritional biomarkers present in coffee, and they are indicators of thermal decomposition during roasting. However, no method is yet available for their simultaneous determination. This paper describes a rapid and validated HPLC-diode array detector method for the simultaneous quantitation of caffeine, trigonelline, nicotinic acid, N-methylpyridinium ion, 5-caffeoylquinic acid, and 5-hydroxymethyl furfural that is applicable to three coffee matrixes: green, roasted, and instant. Baseline separation among all compounds was achieved in 30 min using a phenyl-hexyl RP column (250×4.6 mm, 5 μm particle size), 0.3% aqueous formic buffer (pH 2.4)-methanol mobile phase at a flow rate of 1 mL/min, and a column temperature at 30°C. The method showed good linear correlation (r2>0.9985), precision (less than 3.9%), sensitivity (LOD=0.023-0.237 μg/mL; LOQ=0.069-0.711 μg/mL), and recovery (84-102%) for all compounds. This simplified method is amenable for a more complete routine evaluation of coffee in industry.

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Harmful algal blooms (HABs) are known to produce lipophilic marine biotoxins (LMTs) such as okadaic acid (OA) (and its analogues dinophysistoxins (DTXs)), yessotoxins (YTXs), pectenotoxins (PTXs), and azaspiracids (AZAs), all of which can accumulate in bivalve mollusks and exert noxious effects on humans. Health regulations indicate a limit up to 160 µg/kg for OA/DTXs, PTXs or AZAs, and 3.75 mg/kg for YTXs.Argopecten purpuratus is one of the most important commercial marine products exploited in Perú. Despite its importance and the periodic reports of the presence of HABs in Peruvian coastal waters, the lack of information regarding potential contamination by LMTs is noteworthy.In this work, we report a study performed with 115 samples of A. purpuratus collected between November 2013 and March 2015 from 18 scallop production areas distributed along the Peruvian coast in search of LMTs. To magnify positive results, the hepatopancreas tissue was analyzed by an LC-MS/MS method implemented to quantify OA, YTX, AZA-1, and PTX-2. Baseline separation was achieved in 19 min. The method showed satisfactory linearity (R 2 > 0.997), precision (coefficient of variation < 15 %), and limit of quantification (0.155-0.479 ng/mL). The study revealed the presence of YTX in 72 samples and of PTX-2 in 17 samples, with both biotoxins found at concentrations below the regulatory limits. Free OA and AZA-1 were not detected in any scallop sample. This atypical profile, presence of PTX-2 in the absence of OA, has been previously reported and may be linked to presence of the dinoflagellate D. acuminata . The production of YTX could be associated to the phytoplankton G. spinifera and P. reticulatum .This is the first systematic assessment of the four groups of LMTs in shellfish from Peruvian coastal waters. The results attained suggest low prevalence of marine biotoxins in Peruvian bay scallops yet support the necessity of future surveillance and analysis of LMTs in Perú.

Electronic circular dichroism (ECD) and anisotropy spectra carry information on differential absorption of left-and right-circularly polarized light (LCPL and RCPL) by optically active compounds. This makes them powerful tools for the rapid determination of enantiomeric excesses (ee) in asymmetric synthetic and pharmaceutical chemistry, as well as for predicting the ee inducible by ultraviolet (UV) CPL. The ECD response of a chiral molecule is, however, critically dependent on the properties of the surrounding medium. Here, we report on the first ECD/anisotropy spectra of aqueous solutions of the calcium salt dihydrate of glyceric acid. A systematic study of the effect of the salt concentration and pH on the chiroptical response revealed significant changes and the appearance of a new ECD band of opposite sign. Based on the literature, this can be rationalized by the increase in the relative proportion of free glyceric acid/glycerate to Ca 2+ complexes with glycerate with decreasing salt concentration or pH. Glyceric acid can be readily produced under astrophysical conditions. The anisotropy spectra of the solution containing prevalently the free form of this dihydroxy carboxylic acid resemble the ones of previously investigated aliphatic chain hydroxycarboxylic acids and proteinogenic amino acids. This indicates possible common handedness of stellar CPL-induced asymmetry in the potential comonomers of primitive proto-peptides.alkaline earth metal, chiral hydroxycarboxylic acid, circularly polarized light, complexation, CPL scenario, enantiomeric excess, homochirality | INTRODUCTIONDifferentiation between enantiomers of a chiral species requires a chiral force. Circularly polarized light (CPL) represents a true chiral entity, 1 and the origin of biological homochirality-uniformity of handedness of amino [This article is part of the Special Issue: Chirality in France. See the first articles for this special issue previously published in Volumes 33:9, 33:10, 33:11, 33:12, and 34:1. More special articles will be found in this issue as well as in those to come.]

This work proposes a comprehensive two-dimensional gas chromatography method for the resolution and quantification of 27 amino acids, including 17 enantiomeric pairs, as stable N-trifluoroacetyl-O-methyl ester derivatives. The derivatization approach in combination with enantioselective two-dimensional gas chromatography has proven to be highly responsive with a method detection limit of 1-7 pg even for sterically hindered amino acids such as α,α-dialkylated, and N-alkylated amino acids. Accurate determination of the enantiomeric excess was achieved with errors in the range of ±0.5%-2.5% (1σ) at concentrations ≥10 -6 M. A thorough study of the mass spectra of the amino acid derivatives allowed the fragmentation pathways to be distinguished, enabling chromatographic peaks to be unambiguously assigned. The proposed method is particularly suited for applications that require the precise determination of enantiomeric excesses such as those concerning the role of d-amino acid enantiomers in humans, animals, and the environment, as well as for analyses of extraterrestrial samples aimed at understanding the selection of amino acids in stereochemical l-configuration.

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The diagnosis of neurocysticercosis (NCC) is principally based on neuroimaging (magnetic resonance imaging or computed tomography), instrumentation that is scarcely available in the rural regions where Taenia solium transmission, primarily occurs due to poor sanitation conditions. Immunological assays for antigen or antibody detection complement the neuroimaging approach. However, no field-applicable assays to diagnose viable NCC or to guide the referral of cases for neuroimaging or for appropriate management are available. We performed an exploratory study on urine and serum samples using 1H-nuclear magnetic resonance (NMR)-based metabolomics to discriminate NCC patients (n = 14) from healthy control subjects (n = 22). Metabolic profiles demonstrated a discrimination between the urines of NCC patients and noninfected control subjects with a moderate predictive accuracy (R2 = 0.999, Q2 = 0.434). NMR metabolomics analysis has been proven useful in depicting biomarkers linked to other infectious diseases, various types of cancer, and other disorders. Our results, albeit preliminary, open a door to the development of better methods for detecting NCC through the identification of biomarkers participating in disturbed metabolic pathways.