Liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has the great ability to accurately and precisely quantify various biomolecules, but there is a concern about its ...analysis time, especially during the analysis of a high number of samples. Sample-multiplexing in the same injection is a promising strategy for reducing the total analysis time. This strategy can be accomplished by derivatization of multiple samples with multiple isotopologous reagents. In this study, a sample-triplex LC/ESI-MS/MS assay was developed for quantifying the urinary hexanoylglycine (HG), a diagnostic marker of medium-chain acyl-coenzyme A dehydrogenase deficiency, in three different samples within a single run. For this purpose, the 1-(4-diethylaminophenyl)carbonylpiperazine (DEAPPZ) isotopologues (2H0-, 2H3- and 2H6-forms) were synthesized. When compared to the non-derivatization method, which analyzed one sample in each run, the analysis time after the sample pretreatment was reduced to 55% (390 min → 210 min) for 30 samples in the sample-triplex method, which also had an acceptable precision (intra- and inter-assay precisions; ≤ 5.9% and ≤ 9.1%, respectively) and accuracy (91.7–97.1%). Thus, the sample-triplex strategy using the DEAPPZ isotopologues could successfully reduce the analysis time in the urinary HG quantification.
Amino acids are essential biological compounds in plants as they store nitrogen, an essential nutrient, and are the building blocks for proteins that drive biological activity. Amino acids have been ...studied using a wide variety of analytical techniques in different plant systems, however, mass spectrometry imaging (MSI) is a particularly useful technique as it allows for the simultaneous collection of both chemical and spatial information. In this work, matrix-assisted laser desorption/ionization (MALDI)-MSI is used to study the different localization of free amino acids in the roots of maize inbred lines B73 and Mo17 and their reciprocal hybrids. Because amino acids are difficult to detect in mass spectrometry, especially directly on tissues, a chemical derivatization protocol is utilized to increase the ionization efficiency and improve their detection. We report differences in both abundance and localization of amino acids in B73 and Mo17 maize roots and suggest the hybrids show evidence of inheriting characteristics from both parents. Most genotypic differences are found in the cross-sections near the seed (∼2 cm away) at a later stage of development (10–11 cm in length). Here, B73 has lower amino acid abundance localized primarily to the center of the roots for most amino acids, while Mo17 has much higher abundance localized mainly to the root cortex. This difference in localization is minimized when grown in ammonium ion rich conditions. Roots grown in the presence of
15
N-ammonium ions provided additional insight about the amino acid synthesis. The localization of some amino acids, particularly leucine/isoleucine and glutamine, is not affected by the addition of nitrogen and is consistent regardless of the nitrogen source, either from the seeds (
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N-labeled) or environment (
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N-labeled). Nitrogen uptake from the environment is confined to glutamine, asparagine, and alanine, consistent with their roles in amino acid storage and transportation.
Dissolution of Wood in Ionic Liquids Kilpeläinen, Ilkka; Xie, Haibo; King, Alistair ...
Journal of agricultural and food chemistry,
10/2007, Letnik:
55, Številka:
22
Journal Article
Recenzirano
The present paper demonstrates that both hardwoods and softwoods are readily soluble in various imidazolium-based ionic liquids (ILs) under gentle conditions. More specifically, a variety of ionic ...liquids can only partially dissolve wood chips, whereas ionic liquids such as 1-butyl-3-methylimidazolium chloride and 1-allyl-3-methylimidazolium chloride have good solvating power for Norway spruce sawdust and Norway spruce and Southern pine thermomechanical pulp (TMP) fibers. Despite the fact that the obtained solutions were not fully clear, these ionic liquids provided solutions which permitted the complete acetylation of the wood. Alternatively, transparent amber solutions of wood could be obtained when the dissolution of the same lignocellulosic samples was attempted in 1-benzyl-3-methylimidazolium chloride. This realization was based on a designed augmented interaction of the aromatic character of the cation of the ionic liquid with the lignin in the wood. After dissolution, wood can be regenerated as an amorphous mixture of its original components. The cellulose of the regenerated wood can be efficiently digested to glucose by a cellulase enzymatic hydrolysis treatment. Furthermore, completely acetylated wood was found to be readily soluble in chloroform, allowing, for the first time, detailed proton nuclear magnetic resonance (NMR) spectra and NMR diffusion measurements to be made. It was thus demonstrated that the dissolution of wood in ionic liquids now offers a variety of new possibilities for its structural and macromolecular characterization, without the prior isolation of its individual components. Furthermore, considering the relatively wide solubility and compatibility of ionic liquids with many organic or inorganic functional chemicals or polymers, it is envisaged that this research could create a variety of new strategies for converting abundant woody biomass to valuable biofuels, chemicals, and novel functional composite biomaterials.
This work highlights the discovered in-situ analytical reaction between primary/secondary alcohols and nitrogenous bases (pyridine, quinoline) that involves the substitution of hydroxyl groups for ...nitrogen-containing charged species and proceeds in an ionization region of Direct Analysis in Real Time mass spectrometry (DART-MS) instrument at gas stream temperature of 150–450 °C. Resulted cations provide strong signals in mass spectra and this ensures high sensitivity of the analysis. Collision induced dissociation of such precursor ions gives rise to characteristic and simple fragmentation mass spectra revealing mainly protonated nitrogenous bases and carbonium cations resulting from the elimination of neutral nitrogen-containing bases. The dependence of signal response on gas stream temperature was elucidated. It was also found that, independently of gas stream temperature, high volatility low-molecular weight alcohols did not demonstrate characteristic DART spectra owing to a high rate of desorption/evaporation which does not provide sufficient probability of the reaction. To the best of our knowledge, this type of specific reactions in a plasma-based source of DART mass spectrometer is reported for the first time. It represents a new and interesting derivatization approach providing a rapid and sensitive complement method for the detection and identification of individual monools of various origin, profiling plant sterols and other steroid alcohols in different matrices.
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•Described novel in-situ reaction between alcohols and nitrogenous bases in DART-MS.•Proposed a new method for the rapid and sensitive detection of monools.•The method applied for profiling of sterols in plant oils and sour creams.
A highly sensitive high-performance liquid chromatography method has been developed using the pre-column fluorescent derivatization of daptomycin (DAP) through cyclization of the amino group of ...ornithine with 2,3-naphthalenedialdehyde. With the proposed method, the limits of detection and quantification of DAP in murine serum were 8 and 3 nmol/L, respectively, and the calibration curve was linear across the examined dynamic range from 8 nmol/L to 1 μmol/L (n = 8, r = 0.9986). This method is suitable for animal experiments examining the side effects of DAP therapy using mice as a simple method with quantification to the order of 10 nmol/L.
Background: Lincomycin (LIN) is extensively used for treating diseases in livestock and promoting growth in food animal farming, and it is frequently found in both the environment and in food ...products. Currently, most of the methods for detecting lincomycin either lack sensitivity and precision or require the use of costly equipment such as mass spectrometers. Result: In this study, we developed a reliable high-performance liquid chromatography-ultraviolet detection (HPLC-UVD) method and used it to detect LIN residue in 11 types of matrices (pig liver and muscle; chicken kidney and liver; cow fat, liver and milk; goat muscle, liver and milk; and eggs) for the first time. The tissue homogenates and liquid samples were extracted via liquid–liquid extraction, and subsequently purified and enriched via sorbent and solid phase extraction (SPE). After nitrogen drying, the products were derivatized with p-toluene sulfonyl isocyanic acid (PTSI) (100 µL) for 30 min at room temperature. Finally, the derivatized products were analyzed by HPLC at 227 nm. Under the optimized conditions, the method displayed impressive performance and demonstrated its reliability and practicability, with a limit of detection (LOD) and quantification (LOQ) of LIN in each matrix of 25–40 μg/kg and 40–60 μg/kg, respectively. The recovery ranged from 71.11% to 98.30%. Conclusions: The results showed that this method had great selectivity, high sensitivity, satisfactory recovery and cost-effectiveness—fulfilling the criteria in drug residue and actual detection requirements—and proved to have broad applicability in the field of detecting LIN in animal-derived foods.
•Chiral derivatization reagents with a Cbz group were synthesized.•Enantioseparation of some organic acids derivatized with the reagent was tested.•Reagents with C2 unit-containing imidazolidinone ...afforded effective enantioseparation.•Product ion of monocarboxylate derivatized with the reagent was constant at m/z 91.
A chiral derivatization reagent for application in LC-tandem mass spectrometry (LC-MS/MS)-based detection, benzyl 5-(2-aminoethyl)-3-methyl-4-oxoimidazolidine-1-carboxylate (CIM-C2-NH2), which can react with the carboxyl group, was synthesized. Both chiral and non-chiral organic acids such as lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, acetic acid, succinic acid, tartaric acid, malic acid, and citramalic acid were derivatized with CIM-C2-NH2; their derivatives were analyzed by LC-MS/MS. We investigated the enantioseparation of chiral organic acids on an octadecylsilica column and obtained the resolution values within 1.31–2.19 with a mobile phase of H2O-CH3CN with the exception of malic acid. In contrast, no enantioseparation of the chiral organic acids was observed when benzyl 5-(aminomethyl)-3-methyl-4-oxoimidazolidine-1-carboxylate (CIM-C1-NH2), which bears fewer methylene units than CIM-C2-NH2, was used. In addition, the mass spectra of malic acid, tartaric acid, and succinic acid, which have two carboxyl groups, showed product ions of m/z 278, while those of other organic acids showed product ions of m/z 91, corresponding to the benzyl moiety. The proposed method was applied to analyze organic acids in commercial wine, and some organic acids such as d- and l-lactic acid were successfully detected.
Chemical derivatization-assisted electrospray ionization-triple quadrupole mass spectrometry (ESI-QqQ-MS) has become an efficient tool for the quantification of low-molecular-weight molecules. Many ...studies found that the derivatives of the same analytes derivatized by different derivatization reagents with the same reaction group had different detection sensitivity, even under the same conditions of electrospray ionization-mass spectrometry (ESI-MS). This phenomenon was suggested to be caused by the different modifying groups in the derivatization reagents. However, there is still a lack of systematic study on how modifying groups in the derivatization reagents affect the detection sensitivity of their corresponding derivatives of analytes, especially theoretical investigations. In this study, we employed a quantitative structure-activity relationship (QSAR) modeling approach to explore the relationship between modifying group structures and the detection sensitivity of derivatization reagents and their derivatives during ESI-MS detection. A total of 110 derivatization reagents of the hydrazine family and their hexanal derivatives (substituted hydrazones) were selected as the prototypes to construct QSAR models. The established models suggested that several molecular descriptors, related to hydrophobicity, electronegativity, and molecular shape, were related to the detection sensitivity of hexanal derivatives induced by different modifying groups in the derivatization reagents. Besides, we found that the detection sensitivity of compounds detected in selected ion mode (SIM) showed a positive correlation with that obtained in multiple reaction monitoring mode (MRM), and the ionization efficiency was the key factor on the detection sensitivity in both modes.
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•QSAR models were used to select derivatization reagents for ESI-MS analysis.•How modifying groups in the reagents affect the detection sensitivity of their derivatives was investigated by QSAR models.•Hydrophobicity, electronegativity, and molecular shape was important for rational design of derivatization reagents.•Detection sensitivity of a compound in SIM mode showed a positive correlation with that in MRM mode.
The cell surface membrane proteome is a class of proteins encoded by ∼25% of all protein-coding genes in living organisms and plays a key role in mediating communication between the cells and their ...surrounding environment. However, most cell surface membrane proteins (CSMPs) are naturally expressed at very low levels compared with intracellular proteins. The difficulties in their purification with high specificity further hinder the understanding of their structure and function. In this study, we developed a new photolabeling probe to achieve efficient tagging and facile enrichment of the CSMPs. The probe is composed of a lipid tail for cell surface localization, a polyethylene glycol (PEG) spacer for increased water solubility, two 4-(N-maleimido)benzophenone (MBP) groups for UV-active tagging of the CSMPs, and a biotin tag for subsequent isolation. Application of this photolabeling probe resulted in the successful enrichment and identification of 3098 annotated CSMPs in HT22 cells with close to 70% selectivity. The proposed photolabeling probe and enrichment strategy were demonstrated to be a powerful method for deep cell surface proteome profiling, representing one of the largest groups of current drug targets.
We developed a new photolabeling probe to achieve facile enrichment of cell surface membrane proteins (CSMPs). More than 3000 known CSMPs with approximately 70% enrichment selectivity were achieved, and we can expect it to facilitate basic mechanistic study of CSMPs and drug target screening Display omitted
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