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Phosphatidylcholine (PC) is one of the highest levels of lipids in cell membranes. These lipids play critical roles in lots of bioprocesses, including oxidation, inflammation, carcinogenesis, and the formation of cardiovascular diseases and neurodegenerative diseases. Lipidomics evidence suggested that bioactive compounds could induce PCs regulation, thus ameliorating diseases. Recent lipidomics researches were focused on molecular conversion between lipid categories within a specific organ system. A finite amount of data was reported, indicating lipid regulation over the entire body. In this study, a lipid MS-imaging (MSI) platform was developed on desorption electrospray ionization (DESI) and Q-TOF mass spectrometer. Entire body MSI of zebrafish was achieved. Significant upregulation of selected PCs induced by formononetin was observed in the zebrafish body. The selectivity of PCs' chain length and unsaturation was found with the upregulation. On the other hand, those PCs were found down-regulated in the brain mainly. The Spatial-specific PCs regulation was supported by HPLC-HRMS analysis. Since there was no obvious regulation observed with other lipids classes, it was believed that formononetin initiated spatial specific impact limited on PCs. This suggested a novel mechanism for formononetin's bio-activities. Further investigation on the regulation progress might provide clues to the lipid regulation laws, thus facilitating the study, diagnosis, and treatment of related diseases. In addition, the MSI platform could be beneficial to the research and development of other bio-active compounds.

Polysorbates, a group of nonionic surfactants, are widely used as pharmaceutic excipient. Their quality and safety are closely related to their profiles, including composition, structure, proportion and polyoxyethylene (POE) polymerization degree. However, due to complex composition and similar skeletons, it is difficult and time-consuming to profile and identify them. There is no integrated strategy for routine control. In this paper, an UHPLC-HRMS method was established, and 211 components belonging to 10 species in polysorbate-80 were identified based on their MS/MS data and further confirmed by NMR. A mathematical model was then established to predict all possible components based on the good logarithmic relationship between the POE polymerization degrees and retention times (RTs) of the components for the first time. A database of 853 detected and predicted components of polysorbate-80, -60, -40 and -20 was created. A novel rapid identification strategy was established for comprehensive polysorbate profiling by comparing the exact masses and RTs of the test peaks to the database. This novel strategy was employed to profile polysorbates in 14 pharmaceutic excipients and preparations. Approximately 200 components were identified and semiquantified in each sample, and the number and content of components differed among these samples.

Capillary electrophoresis coupled to mass spectrometry (CE-MS) was used for the analysis of naphthenic acid fraction compounds (NAFCs) of oil sands process-affected water (OSPW). A standard mixture of amine-derivatized naphthenic acids is injected directly onto the CE column and analyzed by CE-MS in less than 15min. Time of flight MS analysis (TOFMS), optimized for high molecular weight ions, showed NAFCs between 250 and 800m/z. With a quadrupole mass analyzer, only low-molecular weight NAFCs (between 100 and 450m/z) are visible under our experimental conditions. Derivatization of NAFCs consisted of two-step amidation reactions mediated by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), or mediated by a mixture of EDC and N-hydroxysuccinimide, in dimethyl sulfoxide, dichloromethane or ethyl acetate. The optimum background electrolyte composition was determined to be 30% (V/V) methanol in water and 2% (V/V) formic acid. NAFCs extracted from OSPW in the Athabasca oil sands region were used to demonstrate the feasibility of CE-MS for the analysis of NAFCs in environmental samples, showing that the labeled naphthenic acids are in the mass range of 350 to 1500m/z.

A field experiment was conducted on silty clay loam soil in the years 2011–2012. Two sesame (Sesamum indicum L.) cultivars (Local Black and Local White) were evaluated using various 3 different sowing dates (20th June, 10th and 30th July) and four agrotechnical level (0, 40, 80 and 120 kg N ha–1) at New Developmental Farm The University of Agriculture, Peshawar, Pakistan. The objective of this study was to evaluate the effects of sowing dates on growth, yield and oil fatty acid composition of two sesame cultivars grown under different nitrogen fertilization. Results showed that cv. Local Black was characterized by significantly higher content of oil (47%), seed yield (696 kg ha–1) and oil yield (335 kg ha–1) while cv. Local White had higher palmitic acid (8%) and linoleic acid (38.7%). Yield and its main components were positively affected by the earlier sowing date. With regard to fatty acid composition, a decrease in oleic and stearic acid and an increase in linoleic and palmitic acid were observed. At early sowing, oleic and palmitic acid decreased whereas linoleic and stearic acid increased. The decrease in the oleic/linoleic acid ratio observed at early sowing, suggests a possible role of temperature on the activity of oleate desaturase in the developing seeds. Intensive technology of cultivation (120 kg N ha–1), compared to the economical technology (40 kg N ha–1), significantly increased the seed yield of both sesame cultivars. This was due to higher number of branches, Capsules m–2, capsules plant–1, seeds capsule–1 and 1000 seed weight (g). The intensive technology of cultivation had a beneficial effect on the content of palmitic acid, linolenic acid and oleic acid in sesame seed.

Fatty acids (FAs) are a group of lipid molecules that are essential to organisms. As potential biomarkers for different diseases, FAs have attracted increasing attention from both biological researchers and the pharmaceutical industry. A sensitive and accurate method for globally profiling and identifying FAs is required for biomarker discovery. The high selectivity and sensitivity of high-performance liquid chromatography-multiple reaction monitoring (HPLC-MRM) gives it great potential to fulfill the need to identify FAs from complicated matrices. This paper developed a new approach for global FA profiling and identification for HPLC-MRM FA data mining. Mathematical models for identifying FAs were simulated using the isotope-induced retention time (RT) shift (IRS) and peak area ratios between parallel isotope peaks for a series of FA standards. The FA structures were predicated using another model based on the RT and molecular weight. Fully automated FA identification software was coded using the Qt platform based on these mathematical models. Different samples were used to verify the software. A high identification efficiency (greater than 75%) was observed when 96 FA species were identified in plasma. This FAs identification strategy promises to accelerate FA research and applications.

Herein, an innovative stable-isotope relative quantification strategy for N-glycans was achieved using a self-designed non-reductive hydrazino-s-triazine deuterated derivative as a labelling reagent combined with mass spectrometry. As much as a 20 Da mass shift could effectively distinguish different forms of N-glycans labelled with normal and heavy hydrazino-s-triazine at the reducing end. Especially for glycans with high molecular weight, qualitative identification could be significantly simplified on account of avoiding isotopic distributions overlapping in the mass spectra. Meanwhile, a deuterium derivative with high purity guaranteed the accuracy of the relative quantification. The obviously undifferentiated response toward normal and heavy hydrazino-s-triazine labelled glycans in electrospray ionization mass spectrometry confirmed the feasibility and reliability of our proposed strategy, which was further demonstrated by relative quantification of the mixtures of labelled N-glycans cleaved from ovalbumin as a model sample. Finally, we adopted human serum as a complex sample and successfully achieved highly accurate detection of 48 N-glycans. The deuterated hydrazino-s-triazine labelling reagent exhibited a great potential to promote the development of highly-efficient, accurate and reliable N-glycan relative quantification in pharmacy and diagnosis research.

In this work, the capability of newly developed hydrophilic interaction liquid chromatography (HILIC) coupled with matrix-assisted laser desorption/ionization-mass spectrometric imaging (MALDI-MSI) platform for quantitative analysis of N-glycans has been demonstrated. As a proof-of-principle experiment, heavy and light stable-isotope labeled hydrazide reagents labeled maltodextrin ladder were used to demonstrate the feasibility of the HILIC-MALDI-MSI platform for reliable quantitative analysis of N-glycans. MALDI-MSI analysis by an Orbitrap mass spectrometer enabled high-resolution and high-sensitivity detection of N-glycans eluted from HILIC column, allowing the re-construction of LC chromatograms as well as accurate mass measurements for structural inference. MALDI-MSI analysis of the collected LC traces showed that the chromatographic resolution was preserved. The N-glycans released from human serum was used to demonstrate the utility of this novel platform in quantitative analysis of N-glycans from a complex sample. Benefiting from the minimized ion suppression provided by HILIC separation, comparison between MALDI-MS and the newly developed platform HILIC-MALDI-MSI revealed that HILIC-MALDI-MSI provided higher N-glycan coverage as well as better quantitation accuracy in the quantitative analysis of N-glycans released from human serum. Graphical abstract Reconstructed chromatograms based on HILIC-MALDI-MSI results of heavy and light labeled maltodextrin enabling quantitative glycan analysis.

Increasing plant density is one of the main approaches of achieving higher yields for modern maize crop. However, there exists leaf redundancy for high-density maize, and leaves of the upper canopy shade more competent leaves at the middle strata. In a two-year field experiments, Jinhai5, a semi-compact corn cultivar, was grown at a density of 105,000 plants ha−1 grown until 3 days after silking (3DAS), when plants were subjected to removal of the uppermost two leaves (S2), four leaves (S4) or six leaves (S6), with no leaf removal as control (S0). We evaluated the effects of leaf removal on N remobilization, photosynthetic capacity of the remaining leaves for N uptake, and N accumulation in kernels. Our present results concluded that, under high plant density, excising the uppermost two leaves promoted N remobilization from vegetative organs to kernels and enhanced photosynthetic capacity for N uptake, leading to an increased N accumulation in kernels (19.6% higher than control). However, four or six uppermost leaves removal reduced N remobilization from stem and photosynthesis for poor N uptake, resulting in 37.5 and 50.2% significantly reduced N accumulation in kernels, respectively.

Atmospheric particle is one of the risk factors for respiratory disease; however, their injury mechanisms are poorly understood, and prevention methods are highly desirable. We constructed artificial PM2.5 (aPM2.5) particles according to the size and composition of actual PM2.5 collected in Beijing. Using these artificial particles, we created an inhalation-injury animal model. These aPM2.5 particles simulate the physical and chemical characteristics of the actual PM2.5, and inhalation of the aPM2.5 in rat results in a time-dependent change in lung suggesting a declined lung function, injury from oxidative stress and inflammation in lung. Thus, this aPM2.5-caused injury animal model may mimic that of the pulmonary injury in human exposed to airborne particles. In addition, polydatin (PD), a resveratrol glucoside that is rich in grapes and red wine, was found to significantly decrease the oxidative potential (OP) of aPM2.5in vitro. Treating the model rats with PD prevented the lung function decline caused by aPM2.5, and reduced the level of oxidative damage in aPM2.5-exposed rats. Moreover, PD inhibited aPM2.5-induced inflammation response, as evidenced by downregulation of white blood cells in bronchoalveolar lavage fluid (BALF), inflammation-related lipids and proinflammation cytokines in lung. These results provide a practical means for self-protection against particulate air pollution.

Triptolide (TP), the major active component in Tripterygium wilfordii Hook. f., is widely used for the treatment of rheumatoid arthritis and autoimmune diseases. However, organ toxicity, especially hepatotoxicity and nephrotoxicity, limits its clinical application. To fully understand the mechanism underlying TP toxicity, iTRAQ-based 2D-LC-MS/MS proteomics is used to detect differentially expressed proteins in the livers and kidneys of mice administered the LD50 dose of TP. Functional annotation revealed that multiple pathways are involved in TP toxicity, including acute-phase response signaling, the antigen presentation pathway, FXR/RXR activation, LPS/IL-1-mediated inhibition of RXR function, and EIF2 signaling. Members of the cytochrome P450 protein family that are involved in fatty acid (FA) metabolism, such as CYP2E1, show significant differences in expression among groups. Additionally, the proteomics data suggested that FAs are involved in TP-induced toxicity. FA analysis is conducted using HPLC-MRM to characterize the differences among various groups exposed to TP for different times. It has been found that 20 FAs in the liver show significant differences in abundance among groups, whereas in the kidneys, six FAs show significant differences in abundance. By integrating the proteomic and targeted FA analyses, it has been found that differently expressed proteins and FAs both participate in pathways including cellular lipolytic activity, peroxisomal fatty acid beta-oxidation, and so on. Our data contribute to understanding the mechanisms underlying TP-induced organ toxicity. The results may help to improve the clinical efficacy and safety of TP in the future.

The combination of aptamer and peroxidase-mimicking DNAzyme within a hairpin structure can form a functional DNA probe. The activities of both aptamer (as biorecognition element) and DNAzyme (as signal amplification element) are blocked via base pairing in the hairpin structure. The presence of target triggers the opening of the hairpin to form target/aptamer complex and releases G-quadruplex sequence which can generate amplified colorimetric signals. In this work, we elaborated a universal and simple procedure to design an efficient and sensitive hairpin probe with suitable functional DNA partners. A fill-in-the-blank process was developed for sequence design, and two key points including the pretreatment of the hairpin probe and the selection of suitable signal transducer sequence were proved to enhance the detection sensitivity. Cocaine was chosen as a model target for a proof of concept. A series of hairpins with different numbers of base pairs in the stem region were prepared. Hairpin-C10 with ten base pairs was screened out and a lowest detectable cocaine concentration of 5 μM by colorimetry was obtained. The proposed functional DNA hairpin showed good selectivity and satisfactory analysis in spiked biologic fluid. The whole "mix-and-measure" detection based on DNA hairpin without the need of immobilization and labeling was indicated to be time and labor saving. The strategy has potential to be transplanted into more smart hairpins toward other targets for general application in bioanalytical chemistry.

A novel pH-responsive coating technique was developed and applied to CE successfully in this paper. The coating was formed by bonding mixed opposite charge poly(acrylic acid) and poly(2-vinylpyridine) randomly onto the inner wall of a silica capillary. The coating processes were first characterized by ellipsometry and atomic force microscopy at macroscale and microscale, respectively. Measurements of EOF were implemented to confirm the coating. Direction and velocity of EOF became controllable from negative to positive, showing a perfect sigmoidal curve as the coating net charges alternated by the pH of BGE. The control of the EOF makes it possible to analyze different kinds of small molecules, peptides, and proteins successfully in the same capillary. Results showed that the stability and reproducibility for separations of fluoroquinolone standards were satisfactory for more than a hundred separations. A series of basic and acidic protein standards were separated with admirable efficiency and minimal adsorption using both polarities. The separation of tryptic BSA digest showed that the prepared capillary has immense potential in analyzing a single sample with both acidic and basic separations, which achieved the expectation in proteomics study by CE-MS.

Eicosanoids are signaling molecules mainly oxidized from arachidonic acid (ARA) and eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA). They have attracted increasing attention from the scientists attributing to their essential physiological functions. However, their quantification have long been challenged by the low abundance, high structure similarity, poor stability and limited ionization efficiency. In this paper, an ultra-high performance liquid chromatograph coupled with tandem mass spectrometry (UPLC-MS/MS) strategy was developed for the comprehensive profiling of more than 60 eicosanoids based on an efficient derivatization reagent 2,4-bis(diethylamino)-6-hydrazino-1,3,5-triazine (T3) and general multiple reaction monitoring (MRM) parameters. Carboxylic acid of eicosanoid was converted to amide in 30 min at 4 °C with derivatization yield larger than 99%. Limits of quantitation (LOQs) for derivatized eicosanoids varied from 0.05 to 50 pg depending on their structures. The sensitivities of derivatized eicosanoids were enhanced by 10- to 5000-folds compared to free eicosanoids. Stabilities of T3 modified eicosanoids were also highly improved compared to free eicosanoids. This new method can also be used to quantify eicosanoids in bio-samples using isotopic internal standards with high efficiency and reliability within 19 min. 46 and 50 eicosanoids in rat plasma and heart tissue from control and acute myocardial ischemia (AMI) model rats were respectively profiled and quantitated using this new method. And 24 of 46 and 25 of 50 eicosanoids were found to be significantly changed between control and model groups. The changed eicosanoids related to AMI modeling were further statistically analyzed and interpreted based on eicosanoid metabolism pathway.

Fatty aldehydes are crucial substances that mediate a wide range of vital physiological functions, particularly lipid peroxidation. Fatty aldehydes such as acrolein and 4-hydroxynonenal (4-HNE) are considered potential biomarkers of myocardial ischemia and dementia, but analytical techniques for fatty aldehydes are lacking. In the present study, a comprehensive characterization strategy with high sensitivity and facility for fatty aldehydes based on derivatization and high-performance liquid chromatography-multiple reaction monitoring (HPLC-MRM) was developed. The fatty aldehydes of a biosample were derivatized using 2,4-bis(diethylamino)-6-hydrazino-1,3,5-triazine under mild and efficient reaction conditions at 37 °C for 15 min. The limit of detection (LOD) of the fatty aldehydes varied from 0.1 to 1 pg/mL, depending on the structures of these molecules. General MRM parameters were forged for the analysis of endogenous fatty aldehydes. "Heavy" derivatization reagents with 20 deuterium atoms were synthesized for both the discovery and comprehensive characterization of fatty aldehydes. More than 80 fatty aldehydes were detected in the biosamples. The new strategy was successfully implemented in global fatty aldehyde profiling of plasma and brain tissue of the bilateral common carotid artery (2VO) dementia rat model. Dozens of fatty aldehydes were significantly changed between the control and model groups. These findings further highlight the importance of endogenous fatty aldehydes.

With the combination of high separation ability of capillary electrophoresis (CE) and strong identification ability of mass spectrometry (MS), CE/MS is becoming a powerful tool for polar and ionic analytes analysis. Different interfaces have been developed to enhance the sensitivity and reliability since the first introduction of CE/MS in 1987. A sheathless porous interface based on a new ions transferring electric connection technique was reported to be with high sensitivity and reliability. In this work, a series of optical and electrochemical experiments were designed to study the electric connection process. The results indicated that closing CE electrical circuit and applying MS spray voltage were achieved by the small ions transferring through the interface porous wall. The new electric connection method significantly enhanced the sensitivity, resolution and stability of the CE/MS analysis. The interface was applied in CE/MS detection of morphine and 6-monoacetylmorphine in urine sample and showed an equal sensitivity to LC/MS. With the significant improvement of sensitivity and stability, the CE/MS with the new interface showed strong potential for the determination of low abundance analytes.

CE features superior separation efficiency, small solvent consumption, as well as the ability to analyze most biomolecules with an open tube fused-silica column. When coupled with MS, the separation power of CE is enhanced by adding another separation dimension based on mass-to-charge ratios. CE-MS reduces the dependence on CE separation so that faster analysis can be achieved. It also yields higher sensitivity as well as the capability for analyte identification and structural elucidation. The use of CE-MS for biomolecule analysis has increased significantly in the last 5 years. New methods are being developed for large molecules, while analyses of smaller molecules are moving toward the study in more complex tissues and other matrices. In this article, the applications of CE-ESI-MS for complex samples in 2007-2011 are reviewed. The applications are categorized according to the types of analytes studied, including the analysis for proteins and peptides, carbohydrates, and small biomolecules. Sample preparation methods, coatings for capillary inner wall, online processing strategies, and other aspects are also reviewed in each category.

Aptamers, which are nucleic acid oligonucleotides that can bind targets with high affinity and specificity, have been widely applied as affinity probes in capillary electrophoresis (CE). Due to relative weak interaction between aptamers and small molecules, the application of aptamer-based CE is still limited in certain compounds. A new strategy that is based on the aptamer structure-switch concept was designed for small molecule detection by a novel CE method. A carboxyfluorescein (fluorescein amidite, FAM) label DNA aptamer was first incubated with partial complementary strand (CS), and then the free aptamer and the aptamer-CS duplex were well separated and determined by metal cation mediated CE/laser-induced fluorescence. When the target was introduced into the incubated sample, the hybridized form was destabilized, resulting in the changes of the fluorescence intensities of the free aptamer and the aptamer-CS duplex. The length of CS was investigated and 12 mer CS showed the best sensitivity for the detection of cocaine. The presented CE-LIF method, which combines the separation power of CE with the specificity of interactions occurring between target, aptamer, and CS, could be a universal detection strategy for other aptamer-specified small molecules.

Oligosaccharides, which exist widely in herbs, present diverse important pharmacological activities. However, the complexity of oligosaccharides seriously challenges their profiling, quality control, and elucidation of activity. In this paper, a novel oligosaccharide analytical method based on a new derivatization pretreatment and ultra-performance liquid chromatography coupled with high resolution tandem mass spectrometry (UPLC-HRMS) procedure was developed to rapidly profile and identify the oligosaccharides of Epimedium. Oligosaccharides are easily derivatized by 2,4-bis(diethylamino)-6-hydrazino-1,3,5-triazine under convenient and mild conditions. Without any further purification steps, oligosaccharides were analyzed by an established UPLC-HRMS/MS method with high sensitivity, good separation efficiency and speed. Benefitting from the derivatization, the oligosaccharides generated a response in the MS two orders of magnitude higher than that of the free oligosaccharide. Oligosaccharides of 52 Epimedium samples were profiled and identified based on the high-resolution mass spectral data. A total of 66 oligosaccharide compounds detected in 52 Epimedium herbs were relatively quantified and statistically processed by principal component analysis (PCA). The 52 Epimedium herbs could be classified into different species based on their oligosaccharide composition and content. Thirteen oligosaccharide compounds demonstrated potential as markers for Epimedium species classification, and their structures were preliminarily identified using MS/MS spectra.

A novel G-quadruplex based two-stage isothermal exponential amplification reaction (GQ-EXPAR) was developed for label-free DNA colorimetric detection in this work. The exponential amplified trigger DNA in the first stage can convert into G-quadruplex sequence EAD2 by a linear amplification circuit in the second stage. Created EAD2 can form G-quadruplex/hemin DNAzyme to act as a direct signal readout element. The GQ-EXPAR combines the exponential amplification of DNA sequence and the peroxidase-mimicking DNAzyme induced signal amplification, which achieves tandem dual-amplification. Taking advantages of isothermal incubation, this label-free homogeneous assay obviates the need of thermal cycling . As no complex synthesis or extra downstream operation is needed, the whole easy handling procedure can be finished in no more than 1h. This assay allows the sensing of the model DNA with the limit of detection to be 2.5pM. Moreover, it demonstrates good discrimination of mismatched sequences. The strategy has also been successfully implemented to sensitively detect Tay-Sachs genetic disorder mutant.

The separation and sequencing of DNA are the main objectives of the Human Genome Project, and this project has also been very useful for gene analysis and disease diagnosis. Capillary electrophoresis (CE) is one of the most common techniques for the separation and analysis of DNA. DNA separations are usually achieved using capillary gel electrophoresis (CGE) mode, in which polymer gel is packed into the capillary. Compared with a traditional CGE matrix, a hydrophilic polymer matrix, which can be adsorb by the capillary wall has numerous advantages, including stability, reproducibility and ease of automation. Various water-soluble additives, such as linear poly(acrylamide) (PAA) and poly(N,N-dimethylacrylamide) (PDMA), have been employed as media. In this study, different star-shaped PDMA polymers were designed and synthesized to achieve lower polymer solution viscosity. DNA separations with these polymers avoid the disadvantages of high viscosity and long separation time while maintaining high resolution (10 bp between 271 bp and 281 bp). The influences of the polymer concentration and structure on DNA separation were also determined in this study; higher polymer concentration yielded better separation performance, and star-like polymers were superior to linear polymers. This work indicates that modification of the polymer structure is a potential strategy for optimizing DNA separation.

In this work, a novel labelling reagent with multi-charges was designed and developed for glycans capillary electrophoresis-mass spectrometry (CE-MS) analysis. Glycans labelled with this reagent have multiple charges. The results showed that the separation efficiencies of glycans were improved and the sensitivities of large glycans were enhanced more than 10 fold.