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Abstract Ten infrequently monitored antibiotics in biosolids were examined in archived American sewage sludges ( n = 79) collected as part of the 2006/2007 U.S. Environmental Protection Agency (EPA) Targeted National Sewage Sludge Survey. This study inspected the occurrence of amoxicillin, ampicillin, erythromycin, furazolidone [proxy metabolite: 3-(2-nitrobenzylidenamino)-2-oxazolidinone (NP-AOZ)], nalidixic acid, oxolinic acid, oxytetracycline, spiramycin, sulfadimidine, and sulfadimethoxine in sewage sludges after nearly a decade in frozen storage. Six antibiotics were detected at the following average concentrations (ng/g dry weight): amoxicillin (1.0), nalidixic acid (19.1), oxolinic acid (2.7), erythromycin (0.6), oxytetracycline (4.5), and ampicillin (14.8). The remaining four were not detected in any samples (

Liquid chromatography tandem mass spectrometry (LC-MS/MS), a widely used method for comparative 'omics analysis, experiences challenges with compound identification due to matrix effects, difficulty in separating isomer and isobaric ions, and long analysis times. Ion mobility spectrometry (IMS) has proven to be useful in separating isomer and isobar ions; however, IMS-MS suffers from decreased peak capacity due to the correlation in ion size and mass. In proof-of-principle experiments, the use of gas-phase hydrogen/deuterium exchange (HDX) combined with IMS-MS/MS techniques is demonstrated to offer advantages for compound identification. Measurements providing unique information for ions include m/z value, drift time in He buffer gas, drift time in He and D2O buffer gases, deuterium incorporation pattern (isotopic distribution), deuterium incorporation pattern after collisional activation, and fragment ion deuterium incorporation pattern upon collision-induced dissociation (CID). These techniques are here shown to be highly reproducible (drift time coefficients of variation < 1.0% and isotopic pattern root-mean-square deviations of 0.5-1.5%) while demonstrating an increased ability to distinguish individual molecules from diverse classes of compounds (peptides, catecholamines, nucleosides, amino acids, etc.). The concept of using such (and similar) information for rapid, high-throughput molecular identification via database searching of standard libraries is briefly discussed, and an example of such usage is presented for a bonafide metabolite extract sample. [ABSTRACT FROM AUTHOR]

Over the last decade, the field of ion mobility-mass spectrometry (IM-MS) has experienced dramatic growth in its application toward ion structure characterization. Enabling advances in instrumentation during this time period include improved conformation resolution and ion sensitivity. Such advances have rendered IM-MS a powerful approach for characterizing samples presenting a diverse array of ion structures. The structural heterogeneity that can be interrogated by IM-MS techniques now ranges from samples containing mixtures of small molecules exhibiting a variety of structural types to those containing very large protein complexes and subcomplexes. In addition to this diversity, IM-MS techniques have been used to probe spontaneous and induced structural transformations occurring in solution or the gas phase. To support these measurement efforts, significant advances have been made in theoretical methods aimed at translating IM-MS data into structural information. These efforts have ranged from providing more reliable trial structures for comparison to the experimental measurements to dramatically reducing the time required to calculate collision cross sections for such structures. In this short review, recent advances in developments in IM-MS instrumentation, techniques, and theory are discussed with regard to their implications for characterization of gas- and solution-phase structural heterogeneity. [ABSTRACT FROM AUTHOR]

Carotenoid identification and quantitation is critical for the development of improved nutrition plant varieties. Industrial analysis of carotenoids is typically carried out on multiple crops with potentially thousands of samples per crop, placing critical needs on speed and broad utility of the analytical methods. Current chromatographic methods for carotenoid analysis have had limited industrial application due to their low throughput, requiring up to 60min for complete separation of all compounds. We have developed an improved UHPLC-UV method that resolves all major carotenoids found in broccoli (Brassica oleracea L. var. italica), carrot (Daucus carota), corn (Zea mays), and tomato (Solanum lycopersicum). The chromatographic method is completed in 13.5min allowing for the resolution of the 11 carotenoids of interest, including the structural isomers lutein/zeaxanthin and α-/β-carotene. Additional minor carotenoids have also been separated and identified with this method, demonstrating the utility of this method across major commercial food crops. [ABSTRACT FROM AUTHOR]