scholarly journals Use of a Mixed Cationic-Reverse Phase Column for Analyzing Small Highly Polar Metabolic Markers in Biological Fluids for Multiclass LC-HRMS Method

2020 ◽  
Vol 10 (20) ◽  
pp. 7137
Author(s):  
Marco Roverso ◽  
Iole Maria Di Gangi ◽  
Gabriella Favaro ◽  
Paolo Pastore ◽  
Sara Bogialli
Keyword(s):  
High Selectivity ◽  
Biological Fluids ◽  
Polar Compounds ◽  
Reverse Phase ◽  
Experimental Conditions ◽  
Metabolic Markers ◽  
Low Concentrations ◽  
Polar Metabolites ◽  
Highly Polar Compounds

The determination of small highly polar metabolites at low concentrations is challenging when reverse-phase (RP) chromatography is used for multiclass analysis. A mixed cationic-RP column coupled to high-resolution tandem MS (HR-MS/MS) was tested for highly polar compounds in biological fluids, i.e., trimethylamine N-oxide (TMAO) and the isobaric molecules beta-methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB). The efficient retention and separation of the above compounds were obtained with common and MS-friendly RP conditions, reaching high selectivity and sensitivity. The method was firstly assessed in plasma and urine, showing good linearity in the range 50–1000 µg/L and 500–10,000 µg/L for TMAO and both BMAA and DAB, respectively. Excellent precision (RDS < 3%) and good accuracies (71–85%) were observed except for BMAA in plasma, whose experimental conditions should be specifically optimized. Preliminary tests performed on compounds with biological relevance and a wider range of polarities proved the effectiveness of this chromatographic solution, allowing the simultaneous analysis of a larger panel of metabolites, from very small and polar compounds, like trimethylamine, to quite lipophilic molecules, such as corticosterone. The proposed LC-HRMS protocol is an excellent alternative to hydrophilic interaction liquid chromatography and ion-pairing RP chromatography, thus providing another friendly analytical tool for metabolomics.

scholarly journals Determination of cellular nicotinic acid-adenine dinucleotide phosphate (NAADP) levels

2004 ◽  
Vol 380 (2) ◽  
pp. 449-454 ◽  
Author(s):  
Dev CHURAMANI ◽  
Elizabeth A. CARREY ◽  
George D. DICKINSON ◽  
Sandip PATEL
Keyword(s):  
Nicotinic Acid ◽  
Radioligand Binding ◽  
Rat Hepatocytes ◽  
Experimental Conditions ◽  
Ligand Interaction ◽  
Human Red Blood Cells ◽  
Enhanced Sensitivity ◽  
Sea Urchin Egg ◽  
Low Concentrations

Nicotinic acid–adenine dinucleotide phosphate (NAADP) is fast emerging as a new intracellular Ca2+-mobilizing messenger. In sea urchin egg homogenates, binding of NAADP to its receptor is not readily reversible; hence, prior incubation with low concentrations of NAADP is more effective in inhibiting subsequent binding of radiolabelled NAADP than incubating the preparation with the two ligands simultaneously [Patel, Churchill and Galione (2000) Biochem. J. 352, 725–729]. We extend this finding to show that NAADP is more effective still in inhibiting the subsequent radioligand binding at lower homogenate concentrations, an effect again quite probably due to the non-reversible nature of the receptor–ligand interaction. Enhanced sensitivity of the preparation to NAADP afforded by simple manipulation of the experimental conditions has been applied to determine low levels of NAADP in acid extracts from human red blood cells, rat hepatocytes and Escherichia coli without interference from NADP breakdown. Our improved method for the quantification of NAADP should prove useful in the further assessment of its signalling role within cells.

Reverse-Phase High Performance Liquid Chromatography of Metal Chelates of 4-(2-Pyridylazo)resorcinol and 4-(2-Thiazolylazo)resorcinol. Simultaneous Determination of Low Concentrations of Co, Ni and Fe

1994 ◽  
Vol 59 (10) ◽  
pp. 2209-2226 ◽  
Author(s):  
Josef Doležal ◽  
Lumír Sommer
Keyword(s):  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Cetyltrimethylammonium Bromide ◽  
Ion Pair ◽  
Metal Chelates ◽  
Reverse Phase ◽  
Rp Hplc ◽  
Low Concentrations ◽  
Methanol Solutions

The behaviour of stable and inert metal chelates of 4-(2-pyridylazo)resorcinol and 4-(2-thiazolylazo)resorcinol in RP HPLC and in its ion-pair modification (IP RP HPLC) on Separon SGX RPS silica gel was studied. Good results were obtained by the ion-pair variant in water methanol solutions at pH 7 in the presence of cetyltrimethylammonium bromide. The technique proved to be convenient for the preconcentration, separation and quantitation of low concentrations of Fe, Co, and Ni in waters.

Reverse Phase HPLC Determination OF 5,6-Dihydro-5-azacytidine in Biological Fluids

1984 ◽  
Vol 7 (7) ◽  
pp. 1433-1453 ◽  
Author(s):  
Philipp N. Huguenin ◽  
Hiremagalur N. Jayaram ◽  
James A. Kelley
Keyword(s):  
Biological Fluids ◽  
Hplc Determination ◽  
Reverse Phase Hplc ◽  
Reverse Phase

Determination of colchicine in biological fluids by reverse-phase HPLC. Variation of colchicine levels in rats

1993 ◽  
Vol 59 (1) ◽  
pp. 15-18 ◽  
Author(s):  
P. Fernandez ◽  
A.M. Bermejo ◽  
M.J. Tabernero ◽  
M. López-Rivadulla ◽  
A. Cruz
Keyword(s):  
Biological Fluids ◽  
Reverse Phase Hplc ◽  
Reverse Phase

Multi-residue Determination of Polar Veterinary Drugs in Livestock and Fishery Products by Liquid Chromatography/Tandem Mass Spectrometry

2015 ◽  
Vol 98 (1) ◽  
pp. 230-247 ◽  
Author(s):  
Maki Kanda ◽  
Takayuki Nakajima ◽  
Hiroshi Hayashi ◽  
Tsuneo Hashimoto ◽  
Setsuko Kanai ◽  
...  
Keyword(s):  
Polar Compounds ◽  
Veterinary Drugs ◽  
Sea Bream ◽  
Residue Determination ◽  
Chicken Muscle ◽  
Key Points ◽  
Liquid Chromatography Tandem Mass ◽  
Fishery Products ◽  
Highly Polar Compounds

Abstract Residues of 37 polar veterinary drugs belonging to six families (quinolones, tetracyclines, macrolides, lincosamides, sulfonamides, and others) in livestock and fishery products were determined using a validated LC-MS/MS method. There were two key points insample preparation. First, extraction was performed with two solutions of different polarity. Highly polar compounds were initiallyextracted with Na2EDTA-McIlvaine's buffer (pH 7.0). Medium polar compounds were then extracted from the same samples with acetonitrile containing 0.1% formic acid. Secondly, cleanup was performed using a single SPE polymercartridge. The first extracted solution was applied to the cartridge. Highly polar compounds were retained on the cartridge. Then, the second extracted solution was applied to the same cartridge. Both highly and medium polar compounds were eluted from the cartridge. This method satisfied the guideline criteria for 37 out of 37 drugs in swine muscle, chicken muscle, bovine muscle, prawn, salmon trout, red sea bream, milk, and honey; 35 out of 37 in egg; and 34 out of 37 in flounder. The LOQ ranged from 0.1 to 5 μg/kg. Residues were detected in 24 out of 110 samples and analyzed using the validated method.

Reverse Phase HPLC Determination of Azq in Biological Fluids

1981 ◽  
Vol 4 (10) ◽  
pp. 1855-1867 ◽  
Author(s):  
James A. Kelley ◽  
Edward D. Siu Chong
Keyword(s):  
Biological Fluids ◽  
Hplc Determination ◽  
Reverse Phase Hplc ◽  
Reverse Phase

scholarly journals Pseudomonas aeruginosastrain MA01 aerobically metabolizes the aminodinitrotoluenes produced by 2,4,6-trinitrotoluene nitro group reduction

1995 ◽  
Vol 41 (11) ◽  
pp. 984-991 ◽  
Author(s):  
Marc A. Alvarez ◽  
Christopher L. Kitts ◽  
Pat J. Unkefer ◽  
James L. Botsford
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Nitro Group ◽  
Electron Acceptor ◽  
Polar Compounds ◽  
Energy Sources ◽  
Aerobic Cometabolism ◽  
Group Reduction ◽  
Polar Metabolites ◽  
Highly Polar Compounds ◽  
Nitro Group Reduction

Many microbes reduce the nitro substituents of 2,4,6-trinitrotoluene (TNT), producing aminodinitrotoluenes (ADNTs). These compounds are recalcitrant to further breakdown and are acutely toxic. In a search for organisms capable of metabolizing ADNTs, a bacterial strain was isolated for the ability to use 2-aminobenzoate (anthranilate) as sole C-source. This isolate, Pseudomonas aeruginosa MA01, metabolized TNT by first reducing one nitro group to form either 2-amino-4,6-dinitrotoluene (2ADNT) or 4-amino-2,6-dinitrotoluene (4ADNT). However, strain MA01 was distinct from other TNT-reducing organisms in that it transformed these compounds into highly polar metabolites through an O2-dependent process. Strain MA01 was able to cometabolize TNT, 2ADNT, and 4ADNT in the presence of a variety of carbon and energy sources. During aerobic cometabolism with succinate, 45% of uniformly ring-labeled [14C]TNT was transformed to highly polar compounds. Aerobic cometabolism of purified [14C]2ADNT and [14C]4ADNT with succinate as C-source produced similar amounts of these polar metabolites. During O2-limited cometabolism with succinate as C-source and nitrate as electron acceptor, less than 8% of the [14C]TNT was transformed to polar metabolites. Purified 2,6-diamino-4-nitrotoluene was not metabolized, and while 2,4-diamino-6-nitrotoluene was acetylated, the product (N-acetyl-2,4-diamino-6-nitrotoluene) was not further metabolized. Therefore, strain MA01 metabolized TNT by oxidation of the ADNTs and not by reduction the remaining nitro groups on the ADNTs.Key words: 2,4,6-trinitrotoluene, aminodinitrotoluene, Pseudomonas aeruginosa, cometabolism.

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