New HST data and modeling reveal a massive planetesimal collision around Fomalhaut.

The apparent detection of an exoplanet orbiting Fomalhaut was announced in 2008. However, subsequent observations of Fomalhaut b raised questions about its status: Unlike other exoplanets, it is bright in the optical and nondetected in the infrared, and its orbit appears to cross the debris ring around the star without the expected gravitational perturbations. We revisit previously published data and analyze additional Hubble Space Telescope (HST) data, finding that the source is likely on a radial trajectory and has faded and become extended. Dynamical and collisional modeling of a recently produced dust cloud yields results consistent with the observations. Fomalhaut b appears to be a directly imaged catastrophic collision between two large planetesimals in an extrasolar planetary system. Similar events should be very rare in quiescent planetary systems of the age of Fomalhaut, suggesting that we are possibly witnessing the effects of gravitational stirring due to the orbital evolution of hypothetical planet(s) around the star.

Studying ultra-complex crude oil mixtures by using high-field asymmetric waveform ion mobility spectrometry (FAIMS) coupled to an electrospray ionisation-LTQ-orbitrap mass spectrometer.

High-field asymmetric waveform ion mobility spectrometry (FAIMS) was coupled directly to an LTQ Orbitrap mass spectrometer to analyze a nitrogen-rich crude oil. Analyzing crude oil is extremely difficult because of the complexity, as up to 100,000 different components can be present. Therefore, simplification of crude oil increases the information content because discrimination and suppression effects are reduced. Here, the first results are presented that show that FAIMS can be an important tool for the simplification of complex mixtures. Additionally, the results show that FAIMS is an excellent tool that allows not only a simplification of such complex mixtures, but also shows the separation of isomeric compounds that have the same elemental composition but different structure and conformation.

Molecular and structural characterization of dissolved organic matter during and post cyanobacterial bloom in Taihu by combination of NMR spectroscopy and FTICR mass spectrometry.

Seasonal molecular changes in dissolved organic matter (DOM) isolated from Tai Lake (Taihu) both during (June) and following (November) an algal bloom event in 2007 were characterized by nuclear magnetic resonance spectroscopy (NMR) and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Considerable biosignatures were present in summer DOM, yet with a near absence of algal extract compounds. Extensive molecular alteration resulting from multistep and massively parallel biotic and subordinated abiotic transformations of algal biomass to DOM included loss and synthesis of carbohydrates, fundamental changes of aromatic compounds and progressive formation of carboxyl-rich alicyclic compounds (CRAM). The DOM transformation from summer to fall resulted in smaller molecules, increased abundance of CHNO continuous molecular series and overall molecular diversity. Analysis of MS-derived compositional networks placed summer DOM in-between the algal extract and fall DOM. Metabolic pathway annotation by means of high-resolution mass analysis provided a wide range of pathways associated with secondary metabolites in DOM and more basic ones like carbohydrate metabolism characteristic of algal extract compounds. Overall, the time-dependent molecular signature of Taihu DOM was likely dominated by microbial metabolism rather than abiotic chemical transformations. Results from this study indicate that high-resolution organic structural spectroscopy resolves meaningful structural detail out of complex environmental mixtures and has the potential to contribute significantly to future functional biodiversity studies.

Capillary electrophoresis for the analysis of paralytic shellfish poisoning toxins in shellfish: comparison of detection methods.

Paralytic shellfish toxins (PSTs) are produced by marine and freshwater microalgae and accumulate in shellfish including mussels, oysters, and scallops, causing possible fatalities when inadvertently consumed. Monitoring of PST content of shellfish is therefore important for food safety, with currently approved methods based on HPLC, using pre- or postcolumn oxidation for fluorescence detection (HPLC-FLD). CE is an attractive alternative for screening and detection of PSTs as it is compatible with miniaturization and could be implemented in portable instrumentation for on-site monitoring. In this study, CE methods were developed for C(4) D, FLD, UV absorption detection, and MS-making this first report of C(4) D and FLD for PSTs detection. Because most oxidized toxins are neutral, MEKC was used in combination with FLD. The developed CZE-UV and CZE-C(4) D methods provide better resolution, selectivity, and separation efficiency compared to CZE-MS and MEKC-FLD. The sensitivity of the CZE-C(4) D and MEKC-FLD methods was superior to UV and MS, with LOD values ranging from 140 to 715 ng/mL for CZE-C(4) D and 60.9 to 104 ng/mL for MEKC-FLD. With the regulatory limit for shellfish samples of 800 ng/mL, the CZE-C(4) D and MEKC-FLD methods were evaluated for the screening and detection of PSTs in shellfish samples. While the CZE-C(4) D method suffered from significant interferences from the shellfish matrix, MEKC-FLD was successfully used for PST screening of a periodate-oxidized mussel sample, with results confirmed by HPLC-FLD. This confirms the potential of MEKC-FLD for screening of PSTs in shellfish samples.

Charge heterogeneity profiling of monoclonal antibodies using low ionic strength ion-exchange chromatography and well-controlled pH gradients on monolithic columns.

In this work, the suitability of employing shallow pH gradients generated using single component buffer systems as eluents through cation-exchange (CEX) monolithic columns is demonstrated for the high-resolution separation of monoclonal antibody (mAb) charge variants in three different biopharmaceuticals. A useful selection of small molecule buffer species is described that can be used within very narrow pH ranges (typically 1 pH unit) defined by their buffer capacity for producing controlled and smooth pH profiles when used together with porous polymer monoliths. Using very low ionic strength eluents also enabled direct coupling with electrospray ionisation mass spectrometry. The results obtained by the developed pH gradient approach for the separation of closely related antibody species appear to be consistent with those obtained by imaged capillary isoelectric focusing (iCE) in terms of both resolution and separation profile. Both determinants of resolution, i.e., peak compression and peak separation contribute to the gains in resolution, evidently through the Donnan potential effect, which is increased by decreasing the eluent concentration, and also through the way electrostatic charges are distributed on the protein surface. Retention mechanisms based on the trends observed in retention of proteins at pH values higher than the electrophoretic pI are also discussed using applicable theories. Employing monolithic ion-exchangers is shown to enable fast method development, short analysis time, and high sample throughput owing to the accelerated mass transport of the monolithic media. The possibility of short analysis time, typically less than 15 min, and high sample throughput is extremely useful in the assessment of charge-based changes to the mAb products, such as during manufacturing or storage.

Epoxy-based monoliths for capillary liquid chromatography of small and large molecules.

A versatile epoxy-based monolith was synthesised by polycondensation polymerisation of glycidyl ether 100 with ethylenediamine using a porogenic system consisting of polyethylene glycol, M(w) = 1000, and 1-decanol. Polymerisation was performed at 80 °C for 22 h. A simple acid hydrolysis of residual epoxides resulted in a mixed diol-amino chemistry. The modified column was used successfully for hydrophilic interaction liquid chromatography (HILIC) of small molecule probes such as nucleic acid bases and nucleosides, benzoic acid derivatives, as well as for peptides released from a tryptic digest of cytochrome c. The mixed-mode chemistry allowed both hydrophilic partitioning and ion-exchange (IEX) interactions to contribute to the separation, providing flexibility in selectivity control. Residual epoxide groups were also exploited for incorporating a mixed IEX chemistry. Alternatively, the surface chemistry of the monolith pore surface rendered hydrophobic via grafting of a co-polymerised hydrophobic hydrogel. The inherent hydrophilicity of the monolith scaffold also enabled high performance separation of proteins under IEX and hydrophobic interaction modes and in the absence of non-specific interactions.

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2010-2012).

CE has been alive for over two decades now, yet its sensitivity is still regarded as being inferior to that of more traditional methods of separation such as HPLC. As such, it is unsurprising that overcoming this issue still generates much scientific interest. This review continues to update this series of reviews, first published in Electrophoresis in 2007, with updates published in 2009 and 2011 and covers material published through to June 2012. It includes developments in the field of stacking, covering all methods from field amplified sample stacking and large volume sample stacking, through to isotachophoresis, dynamic pH junction and sweeping. Attention is also given to online or inline extraction methods that have been used for electrophoresis.

Impact of different ionization methods on the molecular assignments of asphaltenes by FT-ICR mass spectrometry.

Over the years, ultrahigh resolution mass spectrometry has successfully illustrated the extreme complexity of crude oil and related solubility or polarity based fractions on a molecular level. However, the applied ionization technique greatly influences the outcome and may provide misleading information. In this work, we investigate the atmospheric pressure laser ionization (APLI) technique coupled with Fourier transform ion cyclotron resonance mass spectrometer to analyze the asphaltene fraction of a crude oil. These results were compared to data obtained by using other existing atmospheric pressure ionization methods. Furthermore elemental analysis and solid state NMR were used to obtain the bulk characteristics of the asphaltene sample. The results of the different ionization techniques were compared with the bulk properties in order to describe the potential discrimination effects of the ionization techniques that were observed. The results showed that APLI expands the range of the assigned molecules, while retaining information already observed with the generally used ion sources.

Expanding the data depth for the analysis of complex crude oil samples by Fourier transform ion cyclotron resonance mass spectrometry using the spectral stitching method.

RATIONALE: Crude oil samples are very complex mixtures of compounds and only Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides the ultra-high mass resolution necessary to resolve them. However, FT-ICR MS operates best when only a small amount of ions is present during each transient. This cannot be accomplished with crude oil samples without chromatography because more than 50,000 compounds can be present, with the result that species with low intensity may be suppressed and are detected either with low intensity or not at all. METHODS: Spectral stitching was used to overcome the problems associated with suppression effects, where only short mass windows of 30 amu were scanned to reduce the amount of ions present in each individual scan. Afterwards, all the scans were co-added and the subsequent spectrum was used to calculate individual class distributions. RESULTS: A heavy crude oil sample was analyzed using spectral stitching and this approach was compared with analysis using a broadband-method in order to illustrate the enhancement in depth of information. Although both methods took the same analysis time a seven-times increase in the number of detected species was observed when the spectral stitching method was used compared with the commonly applied broadband method in a 900 amu mass window. CONCLUSIONS: Spectral stitching using smaller selected ion monitoring (SIM) windows for complex crude oil samples allows better class distribution to be obtained because less ion suppression is observed.

Targeted and non-targeted boron complex formation followed by electrospray Fourier transform ion cyclotron mass spectrometry: a novel approach for identifying boron esters with natural organic matter.

The formation of boron esters was investigated in peat-soluble humified materials with a detailed molecular-level description of boron-organic interactions. Thousands of individually baseline separated signals were obtained from the analysis of natural organic matter of peat samples, using Fourier transform ion cyclotron resonance mass spectrometry. This technique offers unsurpassed isotope-specific mass resolution that can lead to precise molecular formula assignments by means of mathematical data analysis and visualisation techniques, such as mass defect (Kendrick) or elemental ratio (van Krevelen) plots. The analysis of potential boron binding structures within the sample of natural organic matter was described based on prior results. Herein, we describe an algorithm that can be used to effectively distinguish and filter complexes through data obtained from boron-enriched systems with highly intricate mass spectra, such as natural organic matter.

Analysis of low molecular weight acids by monolithic immobilized pH gradient-based capillary isoelectric focusing coupled with mass spectrometry.

A novel method for the separation and detection of low molecular weight (LMW) acids was developed using monolithic immobilized pH gradient-based capillary isoelectric focusing coupled with mass spectrometry. Two main parameters, focusing conditions and delivery buffer conditions, which might affect separation efficiency, were optimized with the focusing time of 7 min at 350 V/cm and the delivery buffer of 50% (v/v) acetonitrile in 10 mmol/L ammonium formate (pH 3.0). Under these conditions, the linear correlation between the volume of delivery solvent and the pK(a) of the model components was observed. In addition, the separation mechanism of LMW acids was proposed as well. We suppose that this method may provide a useful tool for the characterization of LMW components (e.g. natural organic matter of different origins).

Novel software for data analysis of Fourier transform ion cyclotron resonance mass spectra applied to natural organic matter.

Natural organic matter (NOM) occurs as an extremely complex mixture of large, charged molecules that are formed by secondary synthesis reactions. Due to their nature, their full characterization is an important challenge to scientists specializing in NOM as well as analytical chemistry. Ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis enables the identification of thousands of masses in a single measurement. A major challenge in the data analysis process of NOM using the FT-ICR MS technique is the need to sort the entire data set and to present it in an accessible mode. Here we present a simple targeted algorithm called the David Mass Sort (DMS) algorithm which facilitates the detection and counting of consecutive series of masses correlated to any selected mass spacing. This program searches for specific mass differences among all of the masses in a single spectrum against all of the masses in the same spectrum. As a representative case, the current study focuses on the analysis of the well-characterized Suwannee River humic and fulvic acid (SRHA and SRFA, respectively). By applying this algorithm, we were able to find and assess the amount of singly and doubly charged molecules. In addition we present the capabilities of the program to detect any series of consecutive masses correlated to specific mass spacing, e.g. COO, H(2), OCH(2) and O(2). Under several limitations, these mass spacings may be correlated to both chemical and biochemical changes which occur simultaneously during the formation and/or degradation of large mixtures of compounds.

Preparative free-flow electrophoretic offline ESI-Fourier transform ion cyclotron resonance/MS analysis of Suwannee River fulvic acid.

Free-flow electrophoresis (FFE), a preparative free zone electrophoretic method, was used offline in conjunction with ultrahigh-resolution FT/ion cyclotron resonance -MS to resolve the complexity of Suwannee River fulvic acid (SRFA). Before MS, the FFE separation conditions and the compatibility with ESI were optimized. The constituents in SRFA were effectively separated based on their charge states and sizes. The obtained mass spectra were compared by means of van Krevelen diagrams and the calculated aromaticity indices of the individual constituents were used to describe the distribution of aromatic/unsaturated structures across the FFE-fractionated samples. The consolidated number of ions observed within the individual SRFA fractions were much higher than those of the bulk samples alone, demonstrating extensive ion suppression effects in bulk SRFA likely also operating in the analysis of complex biogeochemical mixtures in flow injection mode. The FFE approach allows for producing sizable amounts of sample from dilute solutions, which can be easily fractionated into dozens of individual samples with the possibility of further in-depth characterization.

Letter: Identification of polyborate ions in aqueous solution by electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry.

Ultra-high-resolution mass spectrometry was used to investigate polyborate species in aqueous solution. The mass spectrum of boric acid revealed clusters of polyborate ions. Constituents with up to 19 B atoms were assigned and 15 species and their relationship were investigated in depth with collision-induced fragmentation. Based on the observed fragments, we proposed herein a potential fragmentation pathway for the observed polyborate molecules.

Total mass difference statistics algorithm: a new approach to identification of high-mass building blocks in electrospray ionization Fourier transform ion cyclotron mass spectrometry data of natural organic matter.

The ultrahigh-resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrum of natural organic matter (NOM) contains several thousand peaks with dozens of molecules matching the same nominal mass. Such a complexity poses a significant challenge for automatic data interpretation, in which the most difficult task is molecular formula assignment, especially in the case of heavy and/or multielement ions. In this study, a new universal algorithm for automatic treatment of FTICR mass spectra of NOM and humic substances based on total mass difference statistics (TMDS) has been developed and implemented. The algorithm enables a blind search for unknown building blocks (instead of a priori known ones) by revealing repetitive patterns present in spectra. In this respect, it differs from all previously developed approaches. This algorithm was implemented in designing FIRAN-software for fully automated analysis of mass data with high peak density. The specific feature of FIRAN is its ability to assign formulas to heavy and/or multielement molecules using "virtual elements" approach. To verify the approach, it was used for processing mass spectra of sodium polystyrene sulfonate (PSS, M(w) = 2200 Da) and polymethacrylate (PMA, M(w) = 3290 Da) which produce heavy multielement and multiply-charged ions. Application of TMDS identified unambiguously monomers present in the polymers consistent with their structure: C(8)H(7)SO(3)Na for PSS and C(4)H(6)O(2) for PMA. It also allowed unambiguous formula assignment to all multiply-charged peaks including the heaviest peak in PMA spectrum at mass 4025.6625 with charge state 6- (mass bias -0.33 ppm). Application of the TMDS-algorithm to processing data on the Suwannee River FA has proven its unique capacities in analysis of spectra with high peak density: it has not only identified the known small building blocks in the structure of FA such as CH(2), H(2), C(2)H(2)O, O but the heavier unit at 154.027 amu. The latter was identified for the first time and assigned a formula C(7)H(6)O(4) consistent with the structure of dihydroxyl-benzoic acids. The presence of these compounds in the structure of FA has so far been numerically suggested but never proven directly. It was concluded that application of the TMDS-algorithm opens new horizons in unfolding molecular complexity of NOM and other natural products.

Combined utilization of ion mobility and ultra-high-resolution mass spectrometry to identify multiply charged constituents in natural organic matter.

Natural organic matter as complex biogeochemical non-repetitive material was investigated with ion mobility mass spectrometry (IMS) and ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) approaches in order to unravel the existence of multiply charged state constituents. Hereby we describe and assign the potential molecular formulae of these doubly charged species, derived from FTICR-MS, and the existence of these species was confirmed via IMS. The parallel application of these powerful techniques enabled the boundaries of the understanding of natural organic matter to be pushed further.

Targeted borate complex formation as followed with electrospray ionization Fourier transform ion cyclotron mass spectrometry: monomolecular model system and polyborate formation.

Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) was applied to identify boric acid(B degrees)/borate(B-) complexes in a monomolecular model system, composed of aqueous caffeic acid and boric acid/borate solutions in various concentration ratios at pH 9.2. Using negative mode electrospray ionization as a 'soft' ionization technique, clusters of polyborate were detected beside the well-known BL degrees , BL- and BL2- complexes. An algorithm for the detection of boron complexes, based on their accurate mass and isotope patterns, is proposed which enabled the assignment of elemental compositions/structural formulae of boron/ligand complexes. We present experimental evidence of self-oligomerization of up to six borate units with caffeic acid, resulting in stable covalently bound polyborate-polyol complexes.

Trends in CE-MS 2005-2006.

CE-MS has gained further attention as a multidimensional analytical approach. The number of publications dealing with this technique is still increasing on the level of application as well as method development-oriented approaches. Additionally, 15 reviews were published the last two years focusing on CE-MS. An overview of all papers found to have been published within 2005 and 2006 is given in tabulated form. Additionally, four promising technical trends are chosen to be presented in detail: (i) chip-based CE-MS, (ii) capillary coatings in CE-MS, (iii) new trends in CEC-MS and (iv) the application of 2-D CE-MS.