Ion chromatography/mass spectrometry for the determination of organic ammonium and sulfate compounds

Conboy, James J.; Henion, Jack D.; Martin, Michael W.; Zweigenbaum, Jerry

doi:10.1021/ac00207a006

Cited by 129 publications

(47 citation statements)

References 29 publications

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“…Urinary ammonium was analyzed by ion chromatography. 38 Titratable acidity in urine was calculated from urinary PO4 excretion, urine pH, and blood pH, with the pK' of PO4 corrected for ionic strength by the method of Schwartz et al 39 Urinary NAE was calculated as ammonium plus titratable acid minus bicarbonate excretion. We measured 1,25(OH) 2 Laboratories, Inc., Minneapolis, MN).…”

Section: Discussionmentioning

confidence: 99%

The Human Response to Acute Enteral and Parenteral Phosphate Loads

Scanni

vonRotz

Jehle

et al. 2014

Journal of the American Society of Nephrology

104

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The human response to acute phosphate (PO4) loading is poorly characterized, and it is unknown whether an intestinal phosphate sensor mechanism exists. Here, we characterized the human mineral and endocrine response to parenteral and duodenal acute phosphate loads. Healthy human participants underwent 36 hours of intravenous (IV; 1.15 [low dose] and 2.30 [high dose] mmol of PO4/kg per 24 hours) or duodenal (1.53 mmol of PO4/kg per 24 hours) neutral sodium PO4 loading. Control experiments used equimolar NaCl loads. Maximum PO4 urinary excretory responses occurred between 12 and 24 hours and were similar for low-dose IV and duodenal infusion. Hyperphosphatemic responses were also temporally and quantitatively similar for low-dose IV and duodenal PO4 infusion. Fractional renal PO4 clearance increased approximately 6-fold (high-dose IV group) and 4-fold (low-dose IV and duodenal groups), and significant reductions in plasma PO4 concentrations relative to peak values occurred by 36 hours, despite persistent PO4 loading. After cessation of loading, frank hypophosphatemia occurred. The earliest phosphaturic response occurred after plasma PO4 and parathyroid hormone concentrations increased. Plasma fibroblast growth factor-23 concentration increased after the onset of phosphaturia, followed by a decrease in plasma 1,25(OH)2D levels; a-Klotho levels did not change. Contrary to results in rodents, we found no evidence for intestinal-specific phosphaturic control mechanisms in humans. Complete urinary phosphate recovery in the IV loading groups provides evidence against any important extrarenal response to acute PO4 loads. Plasma phosphate (PO4) concentration is regulated within narrow limits and is the result of intestinal absorption, influx into and efflux from bone, renal excretion, and modest intestinal secretion. 1 Rapid changes in transcellular distribution are effected primarily by systemic acid-base equilibrium and hormones such as insulin and catecholamines. 2 1,25(OH) 2 D stimulates intestinal PO4 absorption, 4 while parathyroid hormone (PTH) and osteocytederived fibroblast growth factor-23 (FGF-23) are the best-characterized phosphaturic factors. Both inhibit proximal tubular sodium-dependent PO4 reabsorption (via Na/PO4 cotransport, NaPi2a and NaPi2c). 5,6 In addition, a-Klotho is a renal transmembrane and secreted protein that functions as an FGF-23 coreceptor and is phosphaturic independently of However, the relative roles of other phosphaturic agents, such as secreted frizzled related protein (sFRP-4), matrix extracellular phosphoglycoprotein, and FGF-8 are not yet defined in humans.1,25(OH) 2 D, PTH, and FGF-23 regulate PO4 metabolism within a complex system of positive and negative feedback mechanisms (for review, see Bergwitz and Jüppner 8 ). Increases in plasma PO4 concentration stimulate PTH secretion, while proximal tubule 1a-hydroxylase and, therefore,

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Section: Discussionmentioning

confidence: 99%

The Human Response to Acute Enteral and Parenteral Phosphate Loads

Scanni

vonRotz

Jehle

et al. 2014

Journal of the American Society of Nephrology

104

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“…Reversed-phase ion-pairing (RPIP)-HPLC, relying on tetraalkyl ammonium salts, provides excellent chromatographic resolution; however, these ion-pairing reagents are non-volatile and are required at high concentrations, making them incompatible with ESI-MS. Volatile ionpairing reagents (42,43), post-column removal of ion-pairing reagent with an in-line membrane (44), post-column addition of sheath liquid, and the splitting of the eluent flow (45) have all been used to overcome these problems. Recently, heparosan (an unsulfated, carboxyl-containing heparin analog) oligosaccharides have been successfully analyzed by RPIP-HPLC/ESI-MS (46).…”

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confidence: 99%

Liquid Chromatography/Mass Spectrometry Sequencing Approach for Highly Sulfated Heparin-derived Oligosaccharides

Thanawiroon

Rice

Toida

et al. 2004

Journal of Biological Chemistry

145

152

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Liquid chromatography/mass spectrometry (LC/MS)is applied to the analysis of complex mixtures of oligosaccharides obtained through the controlled, heparinase-catalyzed depolymerization of heparin. Reversedphase ion-pairing chromatography, utilizing a volatile mobile phase, results in the high resolution separation of highly sulfated, heparin-derived oligosaccharides. Simultaneous detection by UV absorbance and electrospray ionization-mass spectrometry (ESI-MS) provides important structural information on the oligosaccharide components of this mixture. Highly sensitive and easily interpretable spectra were obtained through post-column addition of tributylamine in acetonitrile. High resolution mass spectrometry afforded elemental composition of many known and previously unknown heparin-derived oligosaccharides. UV in combination with MS detection led to the identification of oligosaccharides arising from the original non-reducing end (NRE) of the heparin chain. The structural identification of these oligosaccharides provided sequence from a reading frame that begins at the non-reducing terminus of the heparin chain. Interestingly, 16 NRE oligosaccharides are observed, having both an even and an odd number of saccharide residues, most of which are not predicted based on biosynthesis or known pathways of heparin catabolism. Quantification of these NRE oligosaccharides afforded a number-averaged molecular weight consistent with that expected for the pharmaceutical heparin used in this analysis. Molecular ions could be assigned for oligosaccharides as large as a tetradecasaccharide, having a mass of 4625 Da and a net charge of ؊32. Furthermore, MS detection was demonstrated for oligosaccharides with up to 30 saccharide units having a mass of >10,000 Da and a net charge of ؊60.The structural elucidation of complex carbohydrates remains one of the most difficult challenges for chemists, often requiring the application of multiple analytical approaches (1-5). Glycosaminoglycans (GAGs), 1 and heparin in particular, have proven to be extremely difficult to analyze because of high negative charge, polydispersity, and sequence heterogeneity (6, 7). Heparin and low molecular weight heparins, prepared through the controlled chemical or enzymatic fragmentation of heparin (8), are widely used as clinical anticoagulants. Despite their medical importance, these drugs are relatively uncharacterized in terms of their chemical structure. Moreover, heparin and the structurally related heparan sulfate exhibit many additional biological activities, making them of great interest in new drug discovery (9). Numerous challenges can arise from the structural investigation of biologically active heparin oligosaccharides, particularly those in recognition systems involving specific protein-carbohydrate interactions (10, 11). Such biologically important oligosaccharides often contain rare sequences (12, 13) and are present only in minute, often picomole quantities. New derivatization methods (14, 15), chromatography (15, 16), electrophoresis-ba...

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“…While mass spectrometers are capable of detecting glycans at a level that is many orders of magnitude lower than amperometric detectors, interfacing this chromatographic technique to MS is not convenient due to the incompatibility of the mobile phases with MS. Several attempts [82][83][84][85][86] were made to address this problem, but neither approach was completely successful.…”

Section: Anion-exchange Chromatography-ms-anion-exchange Chromatograpmentioning

confidence: 99%

New hyphenated methodologies in high‐sensitivity glycoprotein analysis

Novotný

Mechref

2005

J of Separation Science

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High-sensitivity glycoprotein analyses are of particular interest in modern biomedical and clinical research, as well as in the development of recombinant protein products. The evolution of new hyphenated methodologies in high-sensitivity glycoprotein analysis is highlighted in this thematic review. These methodologies include, in particular, capillary LC/MALDI/TOF/TOF MS in conjunction with online permethylation platform, and silica-based lectin microcolumns interfaced to MS. The potential of these methodologies in glycomic and glycoproteomic analysis is demonstrated for model glycoproteins as well as total glycomes and glycoproteomes derived from biological samples. Additionally, the applications of CE-MS, CEC, and nanoLC with graphitized carbon in the areas of glycomics and glycoproteomics are described.

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Ion chromatography/mass spectrometry for the determination of organic ammonium and sulfate compounds

Cited by 129 publications

References 29 publications

The Human Response to Acute Enteral and Parenteral Phosphate Loads

The Human Response to Acute Enteral and Parenteral Phosphate Loads

Liquid Chromatography/Mass Spectrometry Sequencing Approach for Highly Sulfated Heparin-derived Oligosaccharides

New hyphenated methodologies in high‐sensitivity glycoprotein analysis

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