Mass Spectrometric Fingerprinting Research Articles

High density information storage through isotope ratio encoding.

The need for reliable information storage is on a steep rise. Sequence-defined polymers, particularly oligonucleotides, are already in use in several areas, while compound mixtures also offer a simple way for storing information. We investigated the use of a set of isotopologues in information storage by mixing, where the information is stored in the form of a mass spectrometric (MS) fingerprint of the mixture. A small molecule with 24 non-labile and replaceable hydrogen atoms was selected as a model, and a set of components covering the D0-D24 deuteration range were synthesized. Theoretical analysis predicted that by mixing up to 10 out of the prepared components, one can encode over 130 million different combinations and distinguish their MS fingerprints. As a proof of principle, several mixtures predicted to have similar fingerprints were prepared and their MS fingerprints were recorded. From each measured MS fingerprint, we were able to unambiguously identify the actual composition of the mixture. It was also demonstrated that one can make the MS fingerprints of a given mixture unique, thereby making counterfeiting of the stored information very difficult. Finally, the utility of isotope ratio encoding in covalent tagging was also demonstrated.

Mass Spectrometric Fingerprint Mapping Reveals Species-Specific Differences in Plant Polyphenols and Related Bioactivities.

Plant species show large variation in the composition and content of their tannins and other polyphenols. These large metabolites are not easy to measure accurately, but they are important factors for species bioactivity and chemotaxonomy. Here, we used an automated group-specific UHPLC-DAD-MS/MS tool to detect and quantify eight most common polyphenol groups in 31 chemically diverse plant species representing many types of growth forms and evolutionary ages. Ten replicate plants were used for each species and two polyphenol-related bioactivities, i.e., protein precipitation capacity and oxidative activity were measured in all samples as well. By the help of a novel 2D fingerprint mapping tool we were able to visualize the qualitative and quantitative differences between the species in hydrolysable tannins (galloyl and hexahydroxydiphenoyl derivatives), proanthocyanidins (procyanidins and prodelphinidins), flavonols (kaempferol, quercetin and myricetin derivatives) and quinic acid derivatives together with the two bioactivities. The highest oxidative activities were found with species containing ellagitannins (e.g., Quercus robur, Geranium sylvaticum, Lythrum salicaria and Chamaenerion angustifolium) or prodelphinidin-rich proanthocyanidins (e.g., Ribes alpinum, Salix phylicifolia and Lysimachia vulgaris). The best species with high protein precipitation capacity were rich in gallotannins (Acer platanoides and Paeonia lactiflora) or oligomeric ellagitannins (e.g., Comarum palustre, Lythrum salicaria and Chamaenerion angustifolium). These types of tools could prove their use in many types of screening experiments and might reveal even unusually active polyphenol types directly from the crude plant extracts.

Seasonal Variation in Plant Polyphenols and Related Bioactivities across Three Years in Ten Tree Species as Visualized by Mass Spectrometric Fingerprint Mapping.

The currently changing climates and environments place plants under many types of stresses that affect both their survival and levels of chemical defenses. The gradual induction of defenses in stressed plant populations could be monitored on a yearly basis unless a seasonal and yearly variation in natural defense levels obscures such monitoring schemes. Here, we studied the stability of the species-specific polyphenol composition and content of 10 tree species over three growing seasons using five replicate trees per species. We specifically measured hydrolyzable tannins (galloyl and hexahydroxydiphenoyl derivatives), proanthocyanidins (procyanidins and prodelphinidins), flavonols (kaempferol, quercetin and kaempferol derivatives) and quinic acid derivatives with the group-specific UHPLC-DAD-MS/MS tool, together with two bioactivities, the protein precipitation capacity and oxidative activity. With the help of a fingerprint mapping tool, we found out that species differed a lot in their seasonal and between-year variation in polyphenols and that the variation was also partially specific to compound groups. Especially ellagitannins tended to have declining seasonal patterns while the opposite was true for proanthocyanidins. Some of the species showed minimal variation in all measured variables, while others showed even induced levels of certain polyphenol groups during the 3-year study. For every species, we found either species-specific baseline levels in qualitative and quantitative polyphenol chemistry or the compound groups with the most plasticity in their production. The used tools could thus form a good combination for future studies attempting to monitor the overall changes in polyphenol chemistry due to various biotic or abiotic stress factors in plant populations or in more controlled environments.

Mass Spectrometric Fingerprints of Organic Compounds in NaCl-Rich Ice Grains from Europa and Enceladus

Europa and Enceladus, respective moons of Jupiter and Saturn, are prime targets in the exploration of potentially habitable extraterrestrial ocean worlds. Organic material could be incorporated from the ocean into ice grains ejected from the surface or in potential plumes and detected via spacecraft flybys with impact ionization mass spectrometers, such as the SUrface Dust Analyzer (SUDA) onboard Europa Clipper or the Cosmic Dust Analyzer (CDA) onboard the past Cassini mission. Ice grains ejected from both Europa and Enceladus are expected to contain sodium salts, specifically sodium chloride (NaCl), in varying concentrations. Consequently, it is important to understand its effects on the mass spectrometric signatures of organic material in salt-rich ice grains. Previous studies have only focused on the detection of biosignatures, such as amino acids, in salt-rich ice grains. We here perform analogue experiments using the Laser Induced Liquid Beam Ion Desorption (LILBID) technique to study how a wide variety of abiotic and potentially biotic organic molecules could be identified by SUDA-type instruments. We investigate their mass spectral characteristics and detectability at various typical NaCl concentrations expected for salt-rich ice grains and in both cation and anion modes. Results show that organics in salt-rich ice grains can still be detected because of the formation of molecular ions and sodiated and chlorinated species. However, high salt concentrations induce compound- and concentration-dependent suppression effects, depending on the chemical properties and functional groups of the analytes. Our results emphasize the need of both ion modes to detect a wide range of organics embedded in complex matrices and to discriminate between abiotic and potentially biotic species. This work complements a spectral reference library for Europa Clipper and other ocean world missions.

Mass Spectrometric Fingerprints of Bacteria and Archaea for Life Detection on Icy Moons.

The icy moons of the outer Solar System display evidence of subsurface liquid water and, therefore, potential habitability for life. Flybys of Saturn's moon Enceladus by the Cassini spacecraft have provided measurements of material from plumes that suggest hydrothermal activity and the presence of organic matter. Jupiter's moon Europa may have similar plumes and is the target for the forthcoming Europa Clipper mission that carries a high mass resolution and high sensitivity mass spectrometer, called the MAss Spectrometer for Planetary EXploration (MASPEX), with the capability for providing detailed characterization of any organic materials encountered. We have performed a series of experiments using pyrolysis-gas chromatography-mass spectrometry to characterize the mass spectrometric fingerprints of microbial life. A range of extremophile Archaea and Bacteria have been analyzed and the laboratory data converted to MASPEX-type signals. Molecular characteristics of protein, carbohydrate, and lipid structures were detected, and the characteristic fragmentation patterns corresponding to these different biological structures were identified. Protein pyrolysis fragments included phenols, nitrogen heterocycles, and cyclic dipeptides. Oxygen heterocycles, such as furans, were detected from carbohydrates. Our data reveal how mass spectrometry on Europa Clipper can aid in the identification of the presence of life, by looking for characteristic bacterial fingerprints that are similar to those from simple Earthly organisms.

An indirect-calibration method for non-target quantification of trace gases applied to a time series of fourth-generation synthetic halocarbons at the Taunus Observatory (Germany)

Abstract. Production and use of many synthetic halogenated trace gases are regulated internationally due to their contribution to stratospheric ozone depletion or climate change. In many applications they have been replaced by shorter-lived compounds, which have become measurable in the atmosphere as emissions increased. Non-target monitoring of trace gases rather than targeted measurements of well-known substances is needed to keep up with such changes in the atmospheric composition. We regularly deploy gas chromatography (GC) coupled to time-of-flight mass spectrometry (TOF-MS) for analysis of flask air samples and in situ measurements at the Taunus Observatory, a site in central Germany. TOF-MS acquires data over a continuous mass range that enables a retrospective analysis of the dataset, which can be considered a type of digital air archive. This archive can be used if new substances come into use and their mass spectrometric fingerprint is identified. However, quantifying new replacement halocarbons can be challenging, as mole fractions are generally low, requiring high measurement precision and low detection limits. In addition, calibration can be demanding, as calibration gases may not contain sufficiently high amounts of newly measured substances or the amounts in the calibration gas may have not been quantified. This paper presents an indirect data evaluation approach for TOF-MS data, where the calibration is linked to another compound which could be quantified in the calibration gas. We also present an approach to evaluate the quality of the indirect calibration method, select periods of stable instrument performance and determine well suited reference compounds. The method is applied to three short-lived synthetic halocarbons: HFO-1234yf, HFO-1234ze(E), and HCFO-1233zd(E). They represent replacements for longer-lived hydrofluorocarbons (HFCs) and exhibit increasing mole fractions in the atmosphere. The indirectly calibrated results are compared to directly calibrated measurements using data from TOF-MS canister sample analysis and TOF-MS in situ measurements, which are available for some periods of our dataset. The application of the indirect calibration method on several test cases can result in uncertainties of around 6 % to 11 %. For hydro(chloro-)fluoroolefines (denoted H(C)FOs), uncertainties up to 23 % are achieved. The indirectly calculated mole fractions of the investigated H(C)FOs at Taunus Observatory range between measured mole fractions at urban Dübendorf and Jungfraujoch stations in Switzerland.

Establishment of the tandem mass spectrometric fingerprints of taxane-based anticancer compounds.

Compounds in the taxane drug family are among the most successful and effective chemotherapeutic agents used in the treatment of solid tumors, such as breast, ovarian, and prostate cancers. The tandem mass spectrometric (MS/MS) fragmentation behavior of these compounds is described in detail, and a generalized MS/MS fingerprint is established for the first time. Five compounds, namely paclitaxel, docetaxel, cabazitaxel, cephalomannine, and baccatin III, were evaluated. A hybrid quadrupole orthogonal time-of-flight (Q-TOF) mass spectrometer was used to obtain accurate mass measurements, whereas MS/MS and second-generation MS/MS (MS3 ) analyses were performed using a triple quadrupole-linear ion trap mass spectrometer. Both instruments were equipped with an electrospray ionization source operated in the positive ion mode. All taxanes showed an abundant singly charged [M + H]+ species in the single-stage analysis with mass accuracies less than 3ppm. The evaluated compounds exhibited common fragmentation behavior in their MS/MS analysis, which allowed for the production of a universal fragmentation pattern. MS3 experiments confirmed the genesis of the various product ions proposed in the fragmentation pathway. In addition, diagnostic product ions were originated from a cleavage in the ester bond between the core diterpene ring structure and the side chain. Varying functional groups present in these compounds resulted in unique product ions that are specific to each structure. The established MS/MS fingerprints will be used in the near future for identification and for the development of multiple reaction monitoring liquid chromatography-MS/MS quantification methods.

Optimized rapid and reliable identification of Tuber spp. by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

Intentional substitution of food ingredients and misleading or false declarations of food products can lead to large economic damage in the food sector. An example is the truffle, an edible mushroom, with different species having a similar morphology. This makes it difficult to distinguish, for example, the high-quality black Périgord truffle from Europe and the lower quality black truffle from China. To detect and prevent potential food fraud and to be able to carry out quality assurance measures, the demand for suitable, fast and cost-effective examination methods for individual foodstuffs is increasing. In this article we present a method based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), which can differentiate and identify commercial truffles. For this purpose, highly specific mass spectrometric fingerprints of 73 truffle tubers from eight different species were generated. These were checked and compared under the criteria of a score evaluation, their protein spectra, and cluster formation. Standard laboratory equipment was used for this purpose, so that apart from the MALDI-TOF no expensive equipment or reagents were required. The study shows that the MALDI-TOF MS method can distinguish and identify Tuber spp. reliably, quickly and efficiently and can therefore be used for quality assurance and fraud control in the truffle market.

Differentiation between wild and artificial cultivated Stephaniae tetrandrae radix using chromatographic and flow-injection mass spectrometric fingerprints with the aid of principal component analysis.

High‐performance liquid chromatographic (HPLC) and flow‐injection mass spectrometric (FIMS) fingerprinting profiles were used to differentiate between wild and artificial cultivated Stephaniae tetrandrae Radix samples. HPLC and FIMS fingerprints of 15 wild S. tetrandrae Radix samples and 12 artificial cultivated S. tetrandrae Radix samples were obtained and analyzed with the aid of principal component analysis (PCA). PCA of the fingerprints showed that the chemical differences between wild and artificial cultivated S. tetrandrae Radix samples could be differentiated by either HPLC or FIMS fingerprints. The HPLC fingerprints provided more chemical information but required longer analytical time compared with FIMS fingerprints. This study indicated that the wild samples contained higher concentrations of almost all of the major compounds than the cultivated samples. Three characteristic compounds which were responsible for the differences between the samples were tentatively identified with the aid of MS data. Furthermore, these three compounds, tetrandrine (TET), fangchinoline (FAN), and cyclanoline (CYC), were quantified. The HPLC and FIMS fingerprints combined with PCA could be used for quality assessment of wild and artificial cultivated S. tetrandrae Radix samples.

Robust enzymatic-mass spectrometric fingerprinting analysis of the fraction of acetylation of chitosans

We developed a rapid and precise method to determine the fraction of acetylation (FA) of unknown chitosan samples using a combination of enzymatic sample hydrolysis, isotopic labeling, and HILIC-ESI-MS analysis. Chitosans are β-(1,4)-linked, partially N-acetylated and linear polyglucosamines representing an interesting group of functional biopolymers with a broad range of applications. For a better understanding of their structure-function relationships, it is key to have sensitive, accurate structural analysis tools available to determine parameters like the degree of polymerization (DP), fraction of acetylation (FA), or pattern of acetylation (PA). Here, we describe an improved enzymatic/mass spectrometric method for FA analysis of chitosan polymers. In contrast to the original chitinosanase-based mass spectrometric fingerprinting analysis of FA, the new method is independent of the PA and the intermolecular variation in FA (ĐFA) of the chitosan sample. This allows accurate analysis of heterogeneously de-N-acetylated samples representing the majority of commercially available chitosans.

Tandem mass spectrometric analysis of novel caffeine scaffold-based bifunctional compounds for Parkinson's disease.

Novel bifunctional compounds composed of a caffeine scaffold attached to nicotine (C8 -6-N), 1-aminoindan (C8 -6-I), or caffeine (C8 -6-C8 ) were designed as therapeutics or diagnostics for Parkinson's disease (PD). In order to probe their pharmacological and toxicological profile, an appropriate analytical method is required. The goal of this study is to establish a tandem mass spectrometric fingerprint for the development of quantitative and qualitative methods that will aid future assessment of the in vitro and in vivo absorption, distribution, metabolism, excretion (ADME) and pharmacokinetic properties of these lead bifunctional compounds for PD. Accurate mass measurement was performed using a hybrid quadrupole orthogonal time-of-flight mass spectrometer while multistage MS/MS and MS3 analyses were conducted using a triple quadrupole linear ion trap mass spectrometer. Both instruments are equipped with an electrospray ionization (ESI) source and were operated in the positive ion mode. The source and compound parameters were optimized for all three tested bifunctional compounds. The MS/MS analysis indicates that the fragmentation of C8 -6-N and C8 -6-I is driven by the dissociation of the nicotine and 1-aminoindan moieties, respectively, but not caffeine. A significant observation in the MS/MS fragmentation of C8 -6-C8 suggests that a previously reported loss of acetaldehyde during caffeine dissociation is instead a loss of CO2 . The collision-induced tandem mass spectrometry (CID-MS/MS) analysis of these novel bifunctional compounds revealed compound-specific diagnostic product ions and neutral losses for all three tested bifunctional compounds. The established MS/MS fingerprint will be applied to the future development of qualitative and quantitative methods.

The Establishment of Tandem Mass Spectrometric Fingerprints of Phytosterols and Tocopherols and the Development of Targeted Profiling Strategies in Vegetable Oils.

Phytosterols and tocopherols are essential for plant biochemistry, and they possess beneficial health effects for humans. Evaluating the tandem mass spectrometric (MS/MS) behavior of phytosterols and tocopherols is needed for the development of a qualitative and quantitative method for these biologically active plant metabolites. Herein, the MS/MS dissociation behavior of phytosterols and tocopherols is elucidated to establish generalized MS/MS fingerprints. MS/MS and multistage (MS3) analysis revealed common fragmentation behavior among the four tested phytosterols, namely β-sitosterol, stigmasterol, campesterol, and brassicasterol. Similar analysis was conducted for the tocopherols (i.e., alpha (α), beta (β), gamma (γ), and delta (δ)). As such, a universal MS/MS fragmentation pathway for each group was successfully established for the first time. Based on the generalized MS/MS fragmentation behavior of phytosterols, diagnostic product ions were chosen for the development of profiling methods for over 20 naturally occurring phytosterols. A precursor ion scan-triggered-enhanced product ion scan (PIS-EPI) method was established. Due to enhanced chromatographic peaks, multiple ion monitoring-triggered-enhanced product ion scan (MIM-EPI) was employed for confirmation. The screening approach was applied successfully to identify blinded samples obtained from standard mixtures as well as sesame and olive oils. The oil samples contain other phytosterols, and their successful identification indicates that, the generalized MS/MS fragmentation behavior is applicable to various structures of phytosterols. A similar approach was attempted for tocopherols and was only hindered by the low concentration of these bioactive metabolites present in the oil samples.

Enzymatic Production and Enzymatic-Mass Spectrometric Fingerprinting Analysis of Chitosan Polymers with Different Nonrandom Patterns of Acetylation.

Chitosans, a family of ß-(1,4)-linked, partially N-acetylated polyglucosamines, are considered to be among the most versatile and most promising functional biopolymers. Chemical analysis and bioactivity studies revealed that the functionalities of chitosans strongly depend on the polymers' degree of polymerization and fraction of acetylation. More recently, the pattern of acetylation ( PA) has been proposed as another important parameter to influence functionalities of chitosans. We therefore carried out studies on the acetylation pattern of chitosan polymers produced by three recombinant fungal chitin deacetylases (CDAs) originating from different species, namely, Podospora anserina, Puccinia graminis f. sp. tritici, and Pestalotiopsis sp. We analyzed the chitosans by 1H NMR, 13C NMR, and SEC-MALS and established new methods for PA analysis based on enzymatic mass spectrometric fingerprinting and in silico simulations. Our studies strongly indicate that the different CDAs indeed produce chitosans with different PA. Finally, Zimm plot analysis revealed that enzymatically treated polymers differ with respect to their second virial coefficient and radius of gyration indicating an influence of PA on polymer-solvent interactions.

Determination of Variance of Secondary Metabolites in Lettuces Grown Under Different Light Sources by Flow Injection Mass Spectrometric (FIMS) Fingerprinting and ANOVA–PCA

Lettuce (Lactuca sativa L.) is one of the most consumed vegetables in the world and different management practice can result in considerable variability of the secondary metabolites. Flow injection mass spectrometry (FIMS) combined with analysis of variance–principle component analysis (ANOVA–PCA) was used to study differences in the secondary metabolites originating from different lighting conditions (Sunlight, white light, and florescent light) and lettuce varieties (Romaine and Lollo Rossa). Ultra-high-performance liquid chromatography–high-resolution accurate mass spectrometry was used for putative marker compound identification. Quinic acid, caffeic acid, chlorogenic acid, L-chicoric acid, and quercetin malonyl glucoside varied significantly for Romaine lettuce grown under different light conditions. The study showed that the combination of FIMS fingerprinting and ANOVA–PCA can be a useful tool for the characterization of the sources of variance in plant materials regarding to genetic, environmental, and management factors.

Comparison of Ion Mobility Fuzzy Chromatography Mass Spectrometric (imFCMS) Fingerprinting and FCMS Fingerprinting for Differentiation of American Cranberry Cultivars

Fuzzy chromatography mass spectrometric (FCMS) fingerprinting methods in combination with principal component analysis (PCA) and soft independent modeling by class analogy (SIMCA) were developed for phenolic profiling and differentiation of American cranberry cultivars. Two FCMS fingerprinting methods, ion mobility fuzzy chromatography mass spectrometric (imFCMS) and conventional FCMS, are compared in the study. PCA and SIMCA successfully differentiated the cultivars with both methods. The six cultivars used formed three distinct groups in the PCA score plots, and each group contained one wild selection cultivar and its genetically related hybrid(s). Compared with FCMS fingerprinting, imFCMS fingerprinting provided better intra-cultivar sample clustering and inter-cultivar sample separation in PCA and superior sample classification sensitivity in SIMCA. Ultra-performance liquid chromatography–high-resolution mass spectrometry (UPLC–HRMS) analysis was conducted on selected samples to profile the phenolic difference between the cultivars. Compound identification using UPLC–HRMS revealed that flavonoid compounds, including flavonol glycosides, proanthocyanidins and anthocyanins, are major components that contribute to the phenolic profile variation among cultivars.

Real-Time Food Authentication Using a Miniature Mass Spectrometer.

Food adulteration is a threat to public health and the economy. In order to determine food adulteration efficiently, rapid and easy-to-use on-site analytical methods are needed. In this study, a miniaturized mass spectrometer in combination with three ambient ionization methods was used for food authentication. The chemical fingerprints of three milk types, five fish species, and two coffee types were measured using electrospray ionization, desorption electrospray ionization, and low temperature plasma ionization. Minimum sample preparation was needed for the analysis of liquid and solid food samples. Mass spectrometric data was processed using the laboratory-built software MS food classifier, which allows for the definition of specific food profiles from reference data sets using multivariate statistical methods and the subsequent classification of unknown data. Applicability of the obtained mass spectrometric fingerprints for food authentication was evaluated using different data processing methods, leave-10%-out cross-validation, and real-time classification of new data. Classification accuracy of 100% was achieved for the differentiation of milk types and fish species, and a classification accuracy of 96.4% was achieved for coffee types in cross-validation experiments. Measurement of two milk mixtures yielded correct classification of >94%. For real-time classification, the accuracies were comparable. Functionality of the software program and its performance is described. Processing time for a reference data set and a newly acquired spectrum was found to be 12 s and 2 s, respectively. These proof-of-principle experiments show that the combination of a miniaturized mass spectrometer, ambient ionization, and statistical analysis is suitable for on-site real-time food authentication.

Study the effects of drying processes on chemical compositions in daylily flowers using flow injection mass spectrometric fingerprinting method and chemometrics

Daylily flowers is an important vegetable in eastern Asia, widely used in many dishes. Daylily flowers are usually sold in dried forms in the supermarkets. There are a few method for processing fresh daylily flowers, however, no study has been conducted to analyze the effects of the processing methods in the composition of final products. In the present study, a flow-injection mass spectrometric fingerprinting (FIMS) method in combination with principal component analysis (PCA) was used to differentiate two species of daylily flowers (Mengzi and Chongli) with three different treatments (vacuum freeze drying, solar drying and hot-air drying treatments) for each. The results showed the fast and simple FIMS method could successfully differentiate between species (raw material) and treatments among each species. However, the two species could not be discriminated very well after being processed in hot-air drying treatment. The difference in chemical profiles of species and treatments were discussed.

Rapid detection of milk adulteration using intact protein flow injection mass spectrometric fingerprints combined with chemometrics

Flow injection mass spectrometry (FIMS) combined with chemometrics was evaluated for rapidly detecting economically motivated adulteration (EMA) of milk. Twenty-two pure milk and thirty-five counterparts adulterated with soybean, pea, and whey protein isolates at 0.5, 1, 3, 5, and 10% (w/w) levels were analyzed. The principal component analysis (PCA), partial least-squares-discriminant analysis (PLS-DA), and support vector machine (SVM) classification models indicated that the adulterated milks could successfully be classified from the pure milks. FIMS combined with chemometrics might be an effective method to detect possible EMA in milk.

IRMPD Spectroscopy Sheds New (Infrared) Light on the Sulfate Pattern of Carbohydrates.

IR spectroscopy of gas-phase ions is proposed to resolve positional isomers of sulfated carbohydrates. Mass spectrometric fingerprints and gas-phase vibrational spectra in the near and mid-IR regions were obtained for sulfated monosaccharides, yielding unambiguous signatures of sulfated isomers. We report the first systematic exploration of the biologically relevant but notoriously challenging deprotonated state in the near IR region. Remarkably, anions displayed very atypical vibrational profiles, which challenge the well-established DFT (Density Functionnal Theory) modeling. The proposed approach was used to elucidate the sulfate patterns in glycosaminoglycans, a ubiquitous class of mammalian carbohydrates, which is regarded as a major challenge in carbohydrate structural analysis. Isomeric glycosaminoglycan disaccharides from heparin and chondroitin sources were resolved, highlighting the potential of infrared multiple photon dissociation spectroscopy as a novel structural tool for carbohydrates.

Corrigendum to "Bioprospecting of microalgae: Proper extraction followed by high performance liquid chromatographic-high resolution mass spectrometric fingerprinting as key tools for successful metabolom characterization" [J. Chromatogr. B 1015-1016 (2016) 22-23

Corrigendum to "Bioprospecting of microalgae: Proper extraction followed by high performance liquid chromatographic-high resolution mass spectrometric fingerprinting as key tools for successful metabolom characterization" [J. Chromatogr. B 1015-1016 (2016) 22-23